HIGHLIGHTS OF PRESCRIBING INFORMATION
These highlights do not include all the information needed to use NORVIR safely and effectively. See full prescribing information for NORVIR.
NORVIR (ritonavir) capsules, soft gelatin for oral use
Initial U.S. Approval: 1996
WARNING: DRUG-DRUG INTERACTIONS LEADING TO POTENTIALLY SERIOUS AND/OR LIFE THREATENING REACTIONS
FULL PRESCRIBING INFORMATION
Co-administration of NORVIR with several classes of drugs including sedative hypnotics, antiarrhythmics, or ergot alkaloid preparations may result in potentially serious and/or life-threatening adverse events due to possible effects of NORVIR on the hepatic metabolism of certain drugs. Review medications taken by patients prior to prescribing NORVIR or when prescribing other medications to patients already taking NORVIR [see Contraindications (4), Warnings and Precautions (5.1), Drug Interactions (7),and Clinical Pharmacology (12.3)].
General Dosing Guidelines
Patients should be aware that frequently observed adverse events, such as mild to moderate gastrointestinal disturbances and paraesthesias, may diminish as therapy is continued.
Dose modification for NORVIR
Dose reduction of NORVIR is necessary when used with other protease inhibitors: atazanavir, darunavir, fosamprenavir, saquinavir, and tipranavir.
Prescribers should consult the full prescribing information and clinical study information of these protease inhibitors if they are co-administered with a reduced dose of ritonavir [see Warnings and Precautions (5), and Drug Interactions (7)].
Recommended Dosage for treatment of HIV-1
The recommended dosage of ritonavir is 600 mg twice daily by mouth. Use of a dose titration schedule may help to reduce treatment-emergent adverse events while maintaining appropriate ritonavir plasma levels. Ritonavir should be started at no less than 300 mg twice daily and increased at 2 to 3 day intervals by 100 mg twice daily. The maximum dose of 600 mg twice daily should not be exceeded upon completion of the titration.
The recommended dosage of ritonavir in children greater than 1 month is 350 to 400 mg per m2 twice daily by mouth and should not exceed 600 mg twice daily. Ritonavir should be started at 250 mg per m2 twice daily and increased at 2 to 3 day intervals by 50 mg per m2 twice daily. If patients do not tolerate 400 mg per m2 twice daily due to adverse events, the highest tolerated dose may be used for maintenance therapy in combination with other antiretroviral agents, however, alternative therapy should be considered. The use of NORVIR oral solution is recommended for children greater than 1 month who cannot swallow capsules. Please refer to the NORVIR oral solution full prescribing information for pediatric dosage and administration.
- NORVIR (ritonavir) capsules, soft gelatin
- When co-administering NORVIR with other protease inhibitors, see the full prescribing information for that protease inhibitor including contraindication information.
- NORVIR is contraindicated in patients with known hypersensitivity (e.g., toxic epidermal necrolysis (TEN) or Stevens-Johnson syndrome) to ritonavir or any of its ingredients.
- Co-administration of NORVIR with several classes of drugs (including sedative hypnotics, antiarrhythmics, or ergot alkaloid preparations) is contraindicated and may result in potentially serious and/or life-threatening adverse events due to possible effects of NORVIR on the hepatic metabolism of these drugs (see Table 1). Voriconazole and St. John’s Wort are exceptions in that co-administration of NORVIR and voriconazole results in a significant decrease in plasma concentrations of voriconazole, and co-administration of NORVIR with St. John’s Wort may result in decreased ritonavir plasma concentrations.
|*see Drug Interactions (7) for co-administration of sildenafil in patients with erectile dysfunction.
** For additional information for these contraindicated drugs, see also Drug Interactions (7).
|Table 1. Drugs that are Contraindicated with NORVIR|
|Drug Class||Drugs Within Class That Are Contraindicated With NORVIR**||Clinical Comments|
|Alpha1-adrenoreceptor antagonist||Alfuzosin HCL||Potential for hypotension.|
|Antiarrhythmics||Amiodarone, flecainide, propafenone, quinidine||Potential for cardiac arrhythmias.|
|Antifungal||Voriconazole||Co-administration of voriconazole with ritonavir 400 mg every 12 hours significantly decreases voriconazole plasma concentrations and may lead to loss of antifungal response. Voriconazole is contraindicated with ritonavir doses of 400 mg every 12 hours or greater [see Drug Interactions (7.2)].|
|Ergot Derivatives||Dihydroergotamine, ergonovine, ergotamine, methylergonovine||Potential for acute ergot toxicity characterized by vasospasm and ischemia of the extremities and other tissues including the central nervous system.|
|GI Motility Agent||Cisapride||Potential for cardiac arrhythmias.|
|Herbal Products||St. John’s Wort (hypericum perforatum)||Co-administration of NORVIR with St. John’s Wort may result in decreased ritonavir plasma concentrations and may lead to loss of virologic response and possible resistance to NORVIR or to the class of protease inhibitors.|
|HMG-CoA Reductase Inhibitors||Lovastatin, simvastatin||Potential for myopathy including rhabdomyolysis.|
|Neuroleptic||Pimozide||Potential for cardiac arrhythmias.|
|PDE5 enzyme inhibitor||Sildenafil* (Revatio®) only when used for the treatment of pulmonary arterial hypertension (PAH)||A safe and effective dose has not been established when used with ritonavir. There is an increased potential for sildenafil-associated adverse events, including visual abnormalities, hypotension, prolonged erection, and syncope [see Drug Interactions (7)].|
|Sedative/hypnotics||Oral midazolam, triazolam||Prolonged or increased sedation or respiratory depression [see Drug Interactions (7.2)].|
NORVIR is a CYP3A inhibitor. Initiating treatment with NORVIR in patients receiving medications metabolized by CYP3A or initiating medications metabolized by CYP3A in patients already maintained on NORVIR may result in increased plasma concentrations of concomitant medications. Higher plasma concentrations of concomitant medications can result in increased or prolonged therapeutic or adverse effects, potentially leading to severe, life-threatening or fatal events. The potential for drug-drug interactions must be considered prior to and during therapy with NORVIR. Review of other medications taken by patients and monitoring of patients for adverse effects is recommended during therapy with NORVIR.
See Table 1 for a listing of drugs that are contraindicated with NORVIR due to potentially life-threatening adverse events, significant drug interactions, or loss of virologic activity. Also, see Table 4 for a listing of drugs with established and other significant drug interactions [see Contraindications (4), Drug Interactions (7), and Clinical Pharmacology (12.3)].
Hepatic transaminase elevations exceeding 5 times the upper limit of normal, clinical hepatitis, and jaundice have occurred in patients receiving NORVIR alone or in combination with other antiretroviral drugs (see Table 3). There may be an increased risk for transaminase elevations in patients with underlying hepatitis B or C. Therefore, caution should be exercised when administering NORVIR to patients with pre-existing liver diseases, liver enzyme abnormalities, or hepatitis. Increased AST/ALT monitoring should be considered in these patients, especially during the first three months of NORVIR treatment [see Use In Specific Populations (8.6)].
Pancreatitis has been observed in patients receiving NORVIR therapy, including those who developed hypertriglyceridemia. In some cases fatalities have been observed. Patients with advanced HIV-1 disease may be at increased risk of elevated triglycerides and pancreatitis [see Warnings and Precautions (5.8)]. Pancreatitis should be considered if clinical symptoms (nausea, vomiting, abdominal pain) or abnormalities in laboratory values (such as increased serum lipase or amylase values) suggestive of pancreatitis should occur. Patients who exhibit these signs or symptoms should be evaluated and NORVIR therapy should be discontinued if a diagnosis of pancreatitis is made.
Allergic reactions including urticaria, mild skin eruptions, bronchospasm, and angioedema have been reported. Cases of anaphylaxis, toxic epidermal necrolysis (TEN), and Stevens-Johnson syndrome have also been reported. Discontinue treatment if severe reactions develop.
NORVIR should be used with caution in patients with underlying structural heart disease, preexisting conduction system abnormalities, ischemic heart disease, cardiomyopathies, as these patients may be at increased risk for developing cardiac conduction abnormalities.
The impact on the PR interval of co-administration of ritonavir with other drugs that prolong the PR interval (including calcium channel blockers, beta-adrenergic blockers, digoxin and atazanavir) has not been evaluated. As a result, co-administration of ritonavir with these drugs should be undertaken with caution, particularly with those drugs metabolized by CYP3A. Clinical monitoring is recommended [see Drug Interactions (7), and Clinical Pharmacology (12.3)].
Treatment with NORVIR therapy alone or in combination with saquinavir has resulted in substantial increases in the concentration of total cholesterol and triglycerides [see Adverse Reactions (6.1)]. Triglyceride and cholesterol testing should be performed prior to initiating NORVIR therapy and at periodic intervals during therapy. Lipid disorders should be managed as clinically appropriate, taking into account any potential drug-drug interactions with NORVIR and HMG CoA reductase inhibitors [see Contraindications (4), and Drug Interactions (7)].
New onset diabetes mellitus, exacerbation of pre-existing diabetes mellitus, and hyperglycemia have been reported during postmarketing surveillance in HIV-1 infected patients receiving protease inhibitor therapy. Some patients required either initiation or dose adjustments of insulin or oral hypoglycemic agents for treatment of these events. In some cases, diabetic ketoacidosis has occurred. In those patients who discontinued protease inhibitor therapy, hyperglycemia persisted in some cases. Because these events have been reported voluntarily during clinical practice, estimates of frequency cannot be made and a causal relationship between protease inhibitor therapy and these events has not been established.
Immune reconstitution syndrome has been reported in HIV-1 infected patients treated with combination antiretroviral therapy, including NORVIR. During the initial phase of combination antiretroviral treatment, patients whose immune system responds may develop an inflammatory response to indolent or residual opportunistic infections (such as Mycobacterium avium infection, cytomegalovirus, Pneumocystis jiroveci pneumonia (PCP), or tuberculosis), which may necessitate further evaluation and treatment.
Autoimmune disorders (such as Graves’ disease, polymyositis, and Guillain-Barré syndrome) have also been reported to occur in the setting of immune reconstitution, however, the time to onset is more variable, and can occur many months after initiation of treatment.
Redistribution/accumulation of body fat including central obesity, dorsocervical fat enlargement (buffalo hump), peripheral wasting, facial wasting, breast enlargement, and "cushingoid appearance" have been observed in patients receiving antiretroviral therapy. The mechanism and long-term consequences of these events are currently unknown. A causal relationship has not been established.
There have been reports of increased bleeding, including spontaneous skin hematomas and hemarthrosis, in patients with hemophilia type A and B treated with protease inhibitors. In some patients additional factor VIII was given. In more than half of the reported cases, treatment with protease inhibitors was continued or reintroduced. A causal relationship between protease inhibitor therapy and these events has not been established.
Varying degrees of cross-resistance among protease inhibitors have been observed. Continued administration of ritonavir 600 mg twice daily following loss of viral suppression may increase the likelihood of cross-resistance to other protease inhibitors [see Microbiology (12.4)].
Ritonavir has been shown to increase triglycerides, cholesterol, SGOT (AST), SGPT (ALT), GGT, CPK, and uric acid. Appropriate laboratory testing should be performed prior to initiating NORVIR therapy and at periodic intervals or if any clinical signs or symptoms occur during therapy.
- Drug Interactions [see Warnings and Precautions (5.1)]
- Hepatotoxicity [see Warnings and Precautions (5.2)]
- Pancreatitis [see Warnings and Precautions (5.3)]
- Allergic Reactions/Hypersensitivity [see Warnings and Precautions (5.4)]
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.
The safety of NORVIR alone and in combination with other antiretroviral agents was studied in 1,755 adult patients. Table 2 lists treatment-emergent Adverse Reactions (with possible or probable relationship to study drug) occurring in greater than or equal to 1% of adult patients receiving NORVIR in combined Phase II/IV studies.
The most frequently reported adverse drug reactions among patients receiving NORVIR alone or in combination with other antiretroviral drugs were gastrointestinal (including diarrhea, nausea, vomiting, abdominal pain (upper and lower)), neurological disturbances (including paresthesia and oral paresthesia), rash, and fatigue/asthenia.
|Abdominal Pain (upper and lower)*||464||26.4|
|Diarrhea including severe with electrolyte imbalance*||1,192||67.9|
|Gastroesophageal reflux disease (GERD)||19||1.1|
|General disorders and administration site conditions|
|Fatigue including asthenia*||811||46.2|
|Blood bilirubin increased (including jaundice)*||25||1.4|
|Hepatitis (including increased AST, ALT, GGT)*||153||8.7|
|Immune system disorders|
|Hypersensivity including urticatria and face edema*||114||8.2|
|Metabolism and nutrition disorders|
|Edema and peripheral edema*||110||6.3|
|Musculoskeletal and connective tissue disorders|
|Arthralgia and back pain*||326||18.6|
|Myopathy/creatine phosphokinase increased*||66||3.8|
|Nervous system disorders|
|Paresthesia (including oral paresthesia)*||889||50.7|
|Disturbance in attention||44||2.5|
|Renal and urinary disorders|
|Respiratory, thoracic and mediastinal disorders|
|Skin and subcutaneous tissue disorders|
|Rash (includes erythematous and maculopapular)*||475||27.1|
|Flushing, feeling hot*||232||13.2|
|Hypotension including orthostatic hypotension*||30||1.7|
|* Represents a medical concept including several similar MedDRA PTs|
|- Indicates no events reported.|
|Table 3. Percentage of Adult Patients, by Study and Treatment Group, with Chemistry and Hematology Abnormalities
Occurring in greater than 3% of Patients Receiving NORVIR
|Cholesterol||> 240 mg/dL||30.7||44.8||9.3||36.5||8.0||65.2|
|CPK||> 1000 IU/L||9.6||12.1||11.0||9.1||6.3||9.9|
|GGT||> 300 IU/L||1.8||5.2||1.7||19.6||11.3||9.2|
|SGOT (AST)||> 180 IU/L||5.3||9.5||2.5||6.4||7.0||7.8|
|SGPT (ALT)||> 215 IU/L||5.3||7.8||3.4||8.5||4.4||9.2|
|Triglycerides||> 800 mg/dL||9.6||17.2||3.4||33.6||9.4||23.4|
|Triglycerides||> 1500 mg/dL||1.8||2.6||-||12.6||0.4||11.3|
|Triglycerides Fasting||> 1500 mg/dL||1.5||1.3||-||9.9||0.3||-|
|Uric Acid||> 12 mg/dL||-||-||-||3.8||0.2||1.4|
|Hemoglobin||< 8.0 g/dL||0.9||-||-||3.8||3.9||-|
|Neutrophils||≤ 0.5 x 109/L||-||-||-||6.0||8.3||-|
|RBC||< 3.0 x 1012/L||1.8||-||5.9||18.6||24.4||-|
|WBC||< 2.5 x 109/L||-||0.9||6.8||36.9||59.4||3.5|
Vomiting, diarrhea, and skin rash/allergy were the only drug-related clinical adverse events of moderate to severe intensity observed in greater than or equal to 2% of pediatric patients enrolled in NORVIR clinical trials.
The following Grade 3-4 laboratory abnormalities occurred in greater than 3% of pediatric patients who received treatment with NORVIR either alone or in combination with reverse transcriptase inhibitors: neutropenia (9%), hyperamylasemia (7%), thrombocytopenia (5%), anemia (4%), and elevated AST (3%).
The following adverse events have been reported during post-marketing use of NORVIR. Because these reactions are reported voluntarily from a population of unknown size, it is not possible to reliably estimate their frequency or establish a causal relationship to NORVIR exposure.
Body as a Whole
Dehydration, usually associated with gastrointestinal symptoms, and sometimes resulting in hypotension, syncope, or renal insufficiency has been reported. Syncope, orthostatic hypotension, and renal insufficiency have also been reported without known dehydration.
Co-administration of ritonavir with ergotamine or dihydroergotamine has been associated with acute ergot toxicity characterized by vasospasm and ischemia of the extremities and other tissues including the central nervous system.
First-degree AV block, second-degree AV block, third-degree AV block, right bundle branch block have been reported [see Warnings and Precautions (5.5)].
Cardiac and neurologic events have been reported when ritonavir has been co-administered with disopyramide, mexiletine, nefazodone, fluoxetine, and beta blockers. The possibility of drug interaction cannot be excluded.
When co-administering NORVIR with other protease inhibitors (atazanavir, darunavir, fosamprenavir, saquinavir, and tipranavir), see the full prescribing information for that protease inhibitor including important information for drug interactions.
Ritonavir has been found to be an inhibitor of cytochrome P450 3A (CYP3A) and may increase plasma concentrations of agents that are primarily metabolized by CYP3A. Agents that are extensively metabolized by CYP3A and have high first pass metabolism appear to be the most susceptible to large increases in AUC (greater than 3-fold) when co-administered with ritonavir. Thus, co-administration of NORVIR with drugs highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events is contraindicated. Co-administration with other CYP3A substrates may require a dose adjustment or additional monitoring as shown in Table 4.
Ritonavir also inhibits CYP2D6 to a lesser extent. Co-administration of substrates of CYP2D6 with ritonavir could result in increases (up to 2-fold) in the AUC of the other agent, possibly requiring a proportional dosage reduction. Ritonavir also appears to induce CYP3A, CYP1A2, CYP2C9, CYP2C19, and CYP2B6 as well as other enzymes, including glucuronosyl transferase.
Table 4 provides a list of established or potentially clinically significant drug interactions. Alteration in dose or regimen may be recommended based on drug interaction studies or predicted interaction [see Clinical Pharmacology (12.3) for magnitude of interaction].
|Concomitant Drug Class:|
|Effect on Concentration of Ritonavir or Concomitant Drug||Clinical Comments|
|HIV-1 Protease Inhibitor:|
|When co-administered with reduced doses of atazanavir and ritonavir|
↑ atazanavir (↑ AUC, ↑ Cmax, ↑ Cmin)
|Atazanavir plasma concentrations achieved with atazanavir 300 mg once daily and ritonavir 100 mg once daily are higher than those achieved with atazanavir 400 mg once daily. See the complete prescribing information for Reyataz® (atazanavir) for details on co-administration of atazanavir 300 mg once daily with ritonavir 100 mg once daily.|
|HIV-1 Protease Inhibitor:|
|When co-administered with reduced doses of ritonavir|
↑ darunavir (↑ AUC, ↑ Cmax, ↑ Cmin)
|See the complete prescribing information for Prezista® (darunavir) for details on co-administration of darunavir 600 mg twice daily with ritonavir 100 mg twice daily or darunavir 800 mg once daily with ritonavir 100 mg once daily.|
|HIV-1 Protease Inhibitor:|
|When co-administered with reduced doses of ritonavir|
↑ amprenavir (↑ AUC, ↑ Cmax, ↑ Cmin)
|See the complete prescribing information for Lexiva® (fosamprenavir) for details on co-administration of fosamprenavir 700 mg twice daily with ritonavir 100 mg twice daily, fosamprenavir 1400 mg once daily with ritonavir 200 mg once daily or fosamprenavir 1400 mg once daily with ritonavir 100 mg once daily.|
|HIV-1 Protease Inhibitor:|
|When co-administered with reduced doses of indinavir and ritonavir|
↑ indinavir (↔ AUC, ↓ Cmax, ↑ Cmin)
|Alterations in concentrations are noted when reduced doses of indinavir are co-administered with NORVIR.
Appropriate doses for this combination, with respect to efficacy and safety, have not been established.
|HIV-1 Protease Inhibitor:|
|When co-administered with reduced doses of ritonavir|
(↑ AUC, ↑ Cmax, ↑ Cmin)
|See the complete prescribing information for Invirase® (saquinavir) for details on co-administration of saquinavir 1000 mg twice daily with ritonavir 100 mg twice daily.
Saquinavir/ritonavir should not be given together with rifampin, due to the risk of severe hepatotoxicity (presenting as increased hepatic transaminases) if the three drugs are given together.
|HIV-1 Protease Inhibitor:|
|When co-administered with reduced doses of ritonavir|
↑ tipranavir (↑ AUC, ↑ Cmax, ↑ Cmin)
|See the complete prescribing information for Aptivus® (tipranavir) for details on co-administration of tipranavir 500 mg twice daily with ritonavir 200 mg twice daily. There have been reports of clinical hepatitis and hepatic decompensation including some fatalities. All patients should be followed closely with clinical and laboratory monitoring, especially those with chronic hepatitis B or C co-infection, as these patients have an increased risk of hepatotoxicity. Liver function tests should be performed prior to initiating therapy with tipranavir/ritonavir, and frequently throughout the duration of treatment.|
|Non-Nucleoside Reverse Transcriptase Inhibitor:|
|↑ ritonavir (↑AUC, ↑Cmax, ↑ Cmin)||Appropriate doses of this combination with respect to safety and efficacy have not been established.|
|HIV-1 CCR5 – antagonist: maraviroc||↑ maraviroc||Concurrent administration of maraviroc with ritonavir will increase plasma levels of maraviroc. For specific dosage adjustment recommendations, please refer to the complete prescribing information for Selzentry® (maraviroc).|
|Integrase Inhibitor: Raltegravir||↓ raltegravir||The effects of ritonavir on raltegravir with ritonavir dosage regimens greater than 100 mg twice daily have not been evaluated, however raltegravir concentrations may be decreased with ritonavir coadministration.|
|A dose decrease may be needed for these drugs when co-administered with ritonavir.|
|↓ meperidine/ ↑ normeperidine (metabolite)||Dosage increase and long-term use of meperidine with ritonavir are not recommended due to the increased concentrations of the metabolite normeperidine which has both analgesic activity and CNS stimulant activity (e.g., seizures).|
|Ritonavir formulations contain alcohol, which can produce disulfiram-like reactions when co-administered with disulfiram or other drugs that produce this reaction (e.g., metronidazole).|
disopyramide, lidocaine, mexiletine
|↑ antiarrhythmics||Caution is warranted and therapeutic concentration monitoring is recommended for antiarrhythmics when co-administered with ritonavir, if available.|
|Anticancer Agents: |
|↑ anticancer agents||Concentrations of these drugs may be increased when co-administered with ritonavir resulting in the potential for increased adverse events usually associated with these anticancer agents.
For vincristine and vinblastine, consideration should be given to temporarily withholding the ritonavir containing antiretroviral regimen in patients who develop significant hematologic or gastrointestinal side effects when ritonavir is administered concurrently with vincristine or vinblastine. Clinicians should be aware that if the ritonavir containing regimen is withheld for a prolonged period, consideration should be given to altering the regimen to not include a CYP3A or P-gp inhibitor in order to control HIV-1 viral load.
A decrease in the dosage or an adjustment of the dosing interval of nilotinib and dasatinib may be necessary for patients requiring co-administration with strong CYP3A inhibitors such as NORVIR. Please refer to the nilotinib and dasatinib prescribing information for dosing instructions.
|Initial frequent monitoring of the INR during ritonavir and warfarin co-administration is indicated.|
|↑ rivaroxaban||Avoid concomitant use of rivaroxaban and ritonavir. Co-administration of ritonavir and rivaroxaban is expected to result in increased exposure of rivaroxaban which may lead to risk of increased bleeding.|
carbamazepine, clonazepam, ethosuximide
|↑ anticonvulsants||Use with caution. A dose decrease may be needed for these drugs when co-administered with ritonavir and therapeutic concentration monitoring is recommended for these anticonvulsants, if available.|
divalproex, lamotrigine, phenytoin
|↓ anticonvulsants||Use with caution. A dose increase may be needed for these drugs when co-administered with ritonavir and therapeutic concentration monitoring is recommended for these anticonvulsants, if available.|
|↑ antidepressants||A dose decrease may be needed for these drugs when co-administered with ritonavir.|
|↓ bupropion |
↓ active metabolite, hydroxybupropion
|Concurrent administration of bupropion with ritonavir may decrease plasma levels of both bupropion and its active metabolite (hydroxybupropion). Patients receiving ritonavir and bupropion concurrently should be monitored for an adequate clinical response to bupropion.|
|↑ desipramine||Dosage reduction and concentration monitoring of desipramine is recommended.|
|Antidepressant: trazodone||↑ trazodone||Concomitant use of trazodone and NORVIR increases plasma concentrations of trazodone. Adverse events of nausea, dizziness, hypotension and syncope have been observed following co-administration of trazodone and NORVIR. If trazodone is used with a CYP3A4 inhibitor such as ritonavir, the combination should be used with caution and a lower dose of trazodone should be considered.|
|↑ dronabinol||A dose decrease of dronabinol may be needed when co-administered with ritonavir.|
|High doses of ketoconazole or itraconazole (greater than 200 mg per day) are not recommended.
Co-administration of voriconazole and ritonavir doses of 400 mg every 12 hours or greater is contraindicated. Co-administration of voriconazole and ritonavir 100 mg should be avoided, unless an assessment of the benefit/risk to the patient justifies the use of voriconazole.
|↑ colchicine||Patients with renal or hepatic impairment should not be given colchicine with ritonavir.
Treatment of gout flares-co-administration of colchicine in patients on ritonavir:
0.6 mg (one tablet) for one dose, followed by 0.3 mg (half tablet) one hour later. Dose to be repeated no earlier than three days.
Prophylaxis of gout flares-co-administration of colchicine in patients on ritonavir:
If the original colchicine regimen was 0.6 mg twice a day, the regimen should be adjusted to 0.3 mg once a day.
If the original colchicine regimen was 0.6 mg once a day, the regimen should be adjusted to 0.3 mg once every other day.
Treatment of familial Mediterranean fever (FMF)-co-administration of colchicine in patients on ritonavir:
Maximum daily dose of 0.6 mg (may be given as 0.3 mg twice a day).
|↑ clarithromycin||For patients with renal impairment the following dosage adjustments should be considered:
|↑ rifabutin and rifabutin metabolite||Dosage reduction of rifabutin by at least three-quarters of the usual dose of 300 mg per day is recommended (e.g., 150 mg every other day or three times a week). Further dosage reduction may be necessary.|
|↓ ritonavir||May lead to loss of virologic response. Alternate antimycobacterial agents such as rifabutin should be considered (see Antimycobacterial: rifabutin, for dose reduction recommendations).|
|↓ atovaquone||Clinical significance is unknown; however, increase in atovaquone dose may be needed.|
|↑ quinine||A dose decrease of quinine may be needed when co-administered with ritonavir.|
|↑ Beta-Blockers||Caution is warranted and clinical monitoring of patients is recommended. A dose decrease may be needed for these drugs when co-administered with ritonavir.|
|↓ theophylline||Increased dosage of theophylline may be required; therapeutic monitoring should be considered.|
|Calcium channel blockers:|
diltiazem, nifedipine, verapamil
|↑ calcium channel blockers||Caution is warranted and clinical monitoring of patients is recommended. A dose decrease may be needed for these drugs when co-administered with ritonavir.|
|Digoxin||↑ digoxin||Concomitant administration of ritonavir with digoxin may increase digoxin levels. Caution should be exercised when co-administering ritonavir with digoxin, with appropriate monitoring of serum digoxin levels.|
|Endothelin receptor antagonists: bosentan||↑ bosentan||Co-administration of bosentan in patients on ritonavir:
In patients who have been receiving ritonavir for at least 10 days, start bosentan at 62.5 mg once daily or every other day based upon individual tolerability.
Co-administration of ritonavir in patients on bosentan:
Discontinue use of bosentan at least 36 hours prior to initiation of ritonavir.
After at least 10 days following the initiation of ritonavir, resume bosentan at 62.5 mg once daily or every other day based upon individual tolerability.
|HMG-CoA Reductase Inhibitor:|
|Titrate atorvastatin and rosuvastatin dose carefully and use the lowest necessary dose.
If NORVIR is used with another protease inhibitor, see the complete prescribing information for the concomitant protease inhibitor for details on co-administration with atorvastatin and rosuvastatin.
cyclosporine, tacrolimus, sirolimus (rapamycin)
|↑ immunosuppressants||Therapeutic concentration monitoring is recommended for immunosuppressant agents when co-administered with ritonavir.|
|Inhaled or Intranasal|
|↑ glucocorticoids||Concomitant use of ritonavir and fluticasone or other glucocorticoids that are metabolized by CYP3A is not recommended unless the potential benefit of treatment outweighs the risk of systemic corticosteroid effects. Concomitant use may result in increased steroid concentrations and reduced serum cortisol concentrations.
Systemic corticosteroid effects including Cushing's syndrome and adrenal suppression have been reported during postmarketing use in patients when ritonavir has been coadministered with fluticasone propionate or budesonide.
|Long-acting beta-adrenoceptor agonist: salmeterol||↑ salmeterol||Concurrent administration of salmeterol and ritonavir is not recommended. The combination may result in increased risk of cardiovascular adverse events associated with salmeterol, including QT prolongation, palpitations and sinus tachycardia.|
|Dosage increase of methadone may be considered.
Concentrations of fentanyl are expected to increase. Careful monitoring of therapeutic and adverse effects (including potentially fatal respiratory depression) is recommended when fentanyl is concomitantly administered with NORVIR.
perphenazine, risperidone, thioridazine
|↑ neuroleptics||A dose decrease may be needed for these drugs when co-administered with ritonavir.|
|Oral Contraceptives or Patch Contraceptives:|
|↓ ethinyl estradiol||Alternate methods of contraception should be considered.|
|Do not use ritonavir with avanafil because a safe and effective avanafil dosage regimen has not been established.
Particular caution should be used when prescribing sildenafil, tadalafil or vardenafil in patients receiving ritonavir. Coadministration of ritonavir with these drugs is expected to substantially increase their concentrations and may result in an increase in PDE5 inhibitor associated adverse events, including hypotension, syncope, visual changes, and prolonged erection.
Use of PDE5 inhibitors for pulmonary arterial hypertension (PAH):
Sildenafil (Revatio®) is contraindicated when used for the treatment of pulmonary arterial hypertension (PAH) because a safe and effective dose has not been established when used with ritonavir [see Contraindications (4)].
The following dose adjustments are recommended for use of tadalafil (AdcircaTM) with ritonavir:
Co-administration of ADCIRCA in patients on ritonavir:
In patients receiving ritonavir for at least one week, start ADCIRCA at 20 mg once daily. Increase to 40 mg once daily based upon individual tolerability.
Co-administration of ritonavir in patients on ADCIRCA:
Avoid use of ADCIRCA during the initiation of ritonavir. Stop ADCIRCA at least 24 hours prior to starting ritonavir. After at least one week following the initiation of ritonavir, resume ADCIRCA at 20 mg once daily. Increase to 40 mg once daily based upon individual tolerability.
Use of PDE5 inhibitors for the treatment of erectile dysfunction:
It is recommended not to exceed the following doses:
Use with increased monitoring for adverse events.
buspirone, clorazepate, diazepam, estazolam, flurazepam, zolpidem
|↑ sedative/hypnotics||A dose decrease may be needed for these drugs when co-administered with ritonavir.|
|Sedative/hypnotics: Parenteral midazolam||↑ midazolam||Co-administration of oral midazolam with NORVIR is CONTRAINDICATED. Concomitant use of parenteral midazolam with NORVIR may increase plasma concentrations of midazolam. Co-administration should be done in a setting which ensures close clinical monitoring and appropriate medical management in case of respiratory depression and/or prolonged sedation. Dosage reduction for midazolam should be considered, especially if more than a single dose of midazolam is administered.|
|Steroids (systemic): e.g. budesonide, dexamethasone, prednisone||↑ glucocorticoids||Concomitant use of glucocorticoids that are metabolized by CYP3A is not recommended unless the potential benefit of treatment outweighs the risk of systemic corticosteroid effects. Concomitant use may result in increased steroid concentrations and reduced serum cortisol concentrations. This may increase the risk for development of systemic corticosteroid effects including Cushing’s syndrome and adrenal suppression.|
|↑ methamphetamine||Use with caution. A dose decrease of methamphetamine may be needed when co-administered with ritonavir.|
When co-administering NORVIR with other protease inhibitors, see the full prescribing information for the co-administered protease inhibitor including important information for use in special populations.
Antiretroviral Pregnancy Registry: To monitor maternal-fetal outcomes of pregnant women exposed to NORVIR, an Antiretroviral Pregnancy Registry has been established. Physicians are encouraged to register patients by calling 1-800-258-4263.
As of January 2012, the Antiretroviral Pregnancy Registry (APR) has received prospective reports of 3860 exposures to ritonavir containing regimens (1567 exposed in the first trimester and 2293 exposed in the second and third trimester). Birth defects occurred in 35 of the 1567 (2.2%) live births (first trimester exposure) and 59 of the 2293 (2.6%) live births (second/third trimester exposure).
No treatment related malformations were observed when ritonavir was administered to pregnant rats or rabbits. Developmental toxicity observed in rats (early resorptions, decreased fetal body weight and ossification delays and developmental variations) occurred at a maternally toxic dosage at an exposure equivalent to approximately 30% of that achieved with the proposed therapeutic dose. A slight increase in the incidence of cryptorchidism was also noted in rats at an exposure approximately 22% of that achieved with the proposed therapeutic dose.
Developmental toxicity observed in rabbits (resorptions, decreased litter size and decreased fetal weights) also occurred at a maternally toxic dosage equivalent to 1.8 times the proposed therapeutic dose based on a body surface area conversion factor.
The Centers for Disease Control and Prevention recommend that HIV-infected mothers not breastfeed their infants to avoid risking postnatal transmission of HIV. It is not known whether ritonavir is secreted in human milk. Because of both the potential for HIV transmission and the potential for serious adverse reactions in nursing infants, mothers should be instructed not to breastfeed if they are receiving NORVIR.
In HIV-1 infected patients age greater than 1 month to 21 years, the antiviral activity and adverse event profile seen during clinical trials and through postmarketing experience were similar to that for adult patients.
Clinical studies of NORVIR did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.
No dose adjustment of ritonavir is necessary for patients with either mild (Child-Pugh Class A) or moderate (Child-Pugh Class B) hepatic impairment. No pharmacokinetic or safety data are available regarding the use of ritonavir in subjects with severe hepatic impairment (Child-Pugh Class C), therefore, ritonavir is not recommended for use in patients with severe hepatic impairment [see Warnings and Precautions (5.2), and Clinical Pharmacology (12.3)].
Human experience of acute overdose with NORVIR is limited. One patient in clinical trials took NORVIR 1500 mg per day for two days. The patient reported paresthesias which resolved after the dose was decreased. A post-marketing case of renal failure with eosinophilia has been reported with ritonavir overdose.
Treatment of overdose with NORVIR consists of general supportive measures including monitoring of vital signs and observation of the clinical status of the patient. There is no specific antidote for overdose with NORVIR. If indicated, elimination of unabsorbed drug should be achieved by emesis or gastric lavage; usual precautions should be observed to maintain the airway. Administration of activated charcoal may also be used to aid in removal of unabsorbed drug. Since ritonavir is extensively metabolized by the liver and is highly protein bound, dialysis is unlikely to be beneficial in significant removal of the drug. A Certified Poison Control Center should be consulted for up-to-date information on the management of overdose with NORVIR.
Ritonavir is chemically designated as 10-Hydroxy-2-methyl-5-(1-methylethyl)-1- [2-(1-methylethyl)-4-thiazolyl]-3,6-dioxo-8,11-bis(phenylmethyl)-2,4,7,12- tetraazatridecan-13-oic acid, 5-thiazolylmethyl ester, [5S-(5R*,8R*,10R*,11R*)]. Its molecular formula is C37H48N6O5S2, and its molecular weight is 720.95. Ritonavir has the following structural formula:
NORVIR soft gelatin capsules are available for oral administration in a strength of 100 mg ritonavir with the following inactive ingredients: Butylated hydroxytoluene, ethanol, gelatin, iron oxide, oleic acid, polyoxyl 35 castor oil, and titanium dioxide.
Ritonavir is an antiviral drug [see Microbiology (12.4)].
The pharmacokinetics of ritonavir have been studied in healthy volunteers and HIV-1 infected patients (CD4 greater than or equal to 50 cells per µL). See Table 5 for ritonavir pharmacokinetic characteristics.
After a single 600 mg dose under non-fasting conditions, in two separate studies, the soft gelatin capsule (n = 57) formulation yielded a mean ± SD area under the plasma concentration-time curve (AUC) of 121.7 ± 53.8. Relative to fasting conditions, the extent of absorption of ritonavir from the soft gelatin capsule formulation was 13% higher when administered with a meal (615 KCal; 14.5% fat, 9% protein, and 76% carbohydrate).
Nearly all of the plasma radioactivity after a single oral 600 mg dose of 14C-ritonavir oral solution (n = 5) was attributed to unchanged ritonavir. Five ritonavir metabolites have been identified in human urine and feces. The isopropylthiazole oxidation metabolite (M-2) is the major metabolite and has antiviral activity similar to that of parent drug; however, the concentrations of this metabolite in plasma are low. In vitro studies utilizing human liver microsomes have demonstrated that cytochrome P450 3A (CYP3A) is the major isoform involved in ritonavir metabolism, although CYP2D6 also contributes to the formation of M-2.
In a study of five subjects receiving a 600 mg dose of 14C-ritonavir oral solution, 11.3 ± 2.8% of the dose was excreted into the urine, with 3.5 ± 1.8% of the dose excreted as unchanged parent drug. In that study, 86.4 ± 2.9% of the dose was excreted in the feces with 33.8 ± 10.8% of the dose excreted as unchanged parent drug. Upon multiple dosing, ritonavir accumulation is less than predicted from a single dose possibly due to a time and dose-related increase in clearance.
|† SS = steady state; patients taking ritonavir 600 mg q12h.
‡ Single ritonavir 600 mg dose.
* Primarily bound to human serum albumin and alpha-1 acid glycoprotein over the ritonavir concentration range of 0.01 to 30 µg/mL.
|Table 5. Ritonavir Pharmacokinetic Characteristics|
|Parameter||n||Values (Mean ± SD)|
|Vß/F‡||91||0.41 ± 0.25 L/kg|
|t½||3 - 5 h|
|CL/F SS†||10||8.8 ± 3.2 L/h|
|CL/F‡||91||4.6 ± 1.6 L/h|
|CLR||62||< 0.1 L/h|
|Percent Bound*||98 to 99%|
QTcF interval was evaluated in a randomized, placebo and active (moxifloxacin 400 mg once-daily) controlled crossover study in 45 healthy adults, with 10 measurements over 12 hours on Day 3. The maximum mean (95% upper confidence bound) time-matched difference in QTcF from placebo after baseline correction was 5.5 (7.6) milliseconds (msec) for 400 mg twice-daily ritonavir. Ritonavir 400 mg twice daily resulted in Day 3 ritonavir exposure that was approximately 1.5 fold higher than observed with ritonavir 600 mg twice-daily dose at steady state.
PR interval prolongation was also noted in subjects receiving ritonavir in the same study on Day 3. The maximum mean (95% confidence interval) difference from placebo in the PR interval after baseline correction was 22 (25) msec for 400 mg twice-daily ritonavir [see Warnings and Precautions (5.5)].
A study of ritonavir pharmacokinetics in healthy males and females showed no statistically significant differences in the pharmacokinetics of ritonavir. Pharmacokinetic differences due to race have not been identified.
Steady-state pharmacokinetics were evaluated in 37 HIV-1 infected patients ages 2 to 14 years receiving doses ranging from 250 mg per m2 twice-daily to 400 mg per m2 twice-daily in PACTG Study 310, and in 41 HIV-1 infected patients ages 1 month to 2 years at doses of 350 and 450 mg per m2 twice-daily in PACTG Study 345. Across dose groups, ritonavir steady-state oral clearance (CL per F per m2) was approximately 1.5 to 1.7 times faster in pediatric patients than in adult subjects. Ritonavir concentrations obtained after 350 to 400 mg per m2 twice-daily in pediatric patients greater than 2 years were comparable to those obtained in adults receiving 600 mg (approximately 330 mg per m2) twice-daily. The following observations were seen regarding ritonavir concentrations after administration with 350 or 450 mg per m2 twice-daily in children less than 2 years of age. Higher ritonavir exposures were not evident with 450 mg per m2 twice-daily compared to the 350 mg per m2 twice-daily. Ritonavir trough concentrations were somewhat lower than those obtained in adults receiving 600 mg twice-daily. The area under the ritonavir plasma concentration-time curve and trough concentrations obtained after administration with 350 or 450 mg per m2 twice-daily in children less than 2 years were approximately 16% and 60% lower, respectively, than that obtained in adults receiving 600 mg twice-daily.
Ritonavir pharmacokinetics have not been studied in patients with renal impairment, however, since renal clearance is negligible, a decrease in total body clearance is not expected in patients with renal impairment.
Dose-normalized steady-state ritonavir concentrations in subjects with mild hepatic impairment (400 mg twice-daily, n = 6) were similar to those in control subjects dosed with 500 mg twice-daily. Dose-normalized steady-state ritonavir exposures in subjects with moderate hepatic impairment (400 mg twice-daily, n= 6) were about 40% lower than those in subjects with normal hepatic function (500 mg twice-daily, n = 6). Protein binding of ritonavir was not statistically significantly affected by mild or moderately impaired hepatic function. No dose adjustment is recommended in patients with mild or moderate hepatic impairment. However, health care providers should be aware of the potential for lower ritonavir concentrations in patients with moderate hepatic impairment and should monitor patient response carefully. Ritonavir has not been studied in patients with severe hepatic impairment.
Table 6 and Table 7 summarize the effects on AUC and Cmax, with 95% confidence intervals (95% CI), of co-administration of ritonavir with a variety of drugs. For information about clinical recommendations see Table 4 in Drug Interactions (7).
|Table 6. Drug Interactions - Pharmacokinetic Parameters for Ritonavir in the Presence of the Co-administered Drug|
|Co-administered Drug||Dose of Co-administered Drug |
|Dose of NORVIR |
|n||AUC % (95% CI)||Cmax (95% CI)||Cmin (95% CI)|
|Clarithromycin||500 q12h, 4 d||200 q8h, 4 d||22||↑ 12% (2, 23%)||↑ 15% (2, 28%)||↑ 14% (-3, 36%)|
|Didanosine||200 q12h, 4 d||600 q12h, 4 d||12||↔||↔||↔|
|Fluconazole||400 single dose, day 1; |
200 daily, 4 d
|200 q6h, 4 d||8||↑ 12% (5, 20%)||↑ 15% (7, 22%)||↑ 14% (0, 26%)|
|Fluoxetine||30 q12h, 8 d||600 single dose, 1 d||16||↑ 19% (7, 34%)||↔||ND|
|Ketoconazole||200 daily, 7 d||500 q12h, 10 d||12||↑ 18% (-3, 52%)||↑ 10% (-11, 36%)||ND|
|Rifampin||600 or 300 daily, 10 d||500 q12h, 20 d||7, 9*||↓ 35% (7, 55%)||↓ 25% (-5, 46%)||↓ 49% (-14, 91%)|
|Voriconazole||400 q12h, 1 d; then 200 q12h, 8 d||400 q12h, 9 d||↔||↔||ND|
|Zidovudine||200 q8h, 4 d||300 q6h, 4 d||10||↔||↔||↔|
|1 Ritonavir and indinavir were co-administered for 15 days; Day 14 doses were administered after a 15%-fat breakfast (757 Kcal) and 9%-fat evening snack (236 Kcal), and Day 15 doses were administered after a 15%-fat breakfast (757 Kcal) and 32%-fat dinner (815 Kcal). Indinavir Cmin was also increased 4-fold. Effects were assessed relative to an indinavir 800 mg q8h regimen under fasting conditions.
2 Effects were assessed on a dose-normalized comparison to a methadone 20 mg single dose.
3 Sulfamethoxazole and trimethoprim taken as single combination tablet.
4 90% CI presented for R- and S-warfarin AUC and Cmax ratios.
5 This significant increase in plasma fluticasone propionate exposure resulted in a significant decrease (86%) in plasma cortisol AUC.
6 For the reference arm: N=14 for Cmax and AUC(0-inf), and for the test arm: N=13 for Cmax and N=4 for AUC(0-inf).
7 90% CI presented for rivaroxaban
↑ Indicates increase.
↓ Indicates decrease.
↔ Indicates no change.
* Parallel group design; entries are subjects receiving combination and control regimens, respectively.
|Table 7. Drug Interactions - Pharmacokinetic Parameters for Co-administered Drug in the Presence of NORVIR|
|Co-administered Drug||Dose of Co-administered Drug|
|Dose of NORVIR |
|n||AUC % (95% CI)||Cmax (95% CI)||Cmin (95% CI)|
|Alprazolam||1, single dose||500 q12h, 10 d||12||↓ 12% (-5, 30%)||↓ 16% (5, 27%)||ND|
|Avanafil||50, single dose||600 q12h||146||↑ 13-fold||↑ 2.4-fold||ND|
|500 q12h, 4 d||200 q8h, 4 d||22||↑ 77% (56, 103%)|
|↑ 31% (15, 51%)|
|↑ 2.8-fold (2.4, 3.3X)
|100, single dose||500 q12h, 12 d||14||↑ 145% (103, 211%)|
↓ 15% (3, 26%)
|↑ 22% (12, 35%)|
↓ 67% (62, 72%)
|Didanosine||200 q12h, 4 d||600 q12h, 4 d||12||↓ 13% (0, 23%)||↓ 16% (5, 26%)||↔|
|Ethinyl estradiol||50 µg single dose||500 q12h, 16 d||23||↓ 40% (31, 49%)||↓ 32% (24, 39%)||ND|
|Fluticasone propionate aqueous nasal spray||200 mcg qd, 7 d||100 mg q12h, 7 d||18||↑ approximately 350-fold5||↑ approximately 25-fold5|
|400 q12h, 15 d||400 q12h, 15 d||10||
↑ 6% (-14, 29%)
↓ 7% (-22, 28%)
↓ 51% (40, 61%)
↓ 62% (52, 70%)
|↑ 4-fold (2.8, 6.8X)
↑ 4-fold (2.5, 6.5X)
|Ketoconazole||200 daily, 7 d||500 q12h, 10 d||12||↑ 3.4-fold (2.8, 4.3X)||↑ 55% (40, 72%)||ND|
|50 oral single dose||500 q12h, 10 d||8|
|↓ 62% (59, 65%)|
↑ 47% (-24, 345%)
|↓ 59% (42, 72%)|
↑ 87% (42, 147%)
|Methadone2||5, single dose||500 q12h, 15 d||11||↓ 36% (16, 52%)||↓ 38% (28, 46%)||ND|
|Raltegravir||400, single dose||100 q12h, 16 d||10||↓ 16% (-30, 1%)||↓ 24% (-45, 4%)||↓ 1% (-30, 40%)|
|Rivaroxaban||10, single dose |
(days 0 and 7)
|600 q12h |
(days 2 to 7)
|12||↑ 150% (130-|
|↑ 60% (40-|
25-O-desacetyl rifabutin metabolite
|150 daily, 16 d||500 q12h, 10 d||5,|
|↑ 4-fold (2.8, 6.1X)|
↑ 38-fold (28, 56X)
|↑ 2.5-fold (1.9, 3.4X)|
↑ 16-fold (13, 20X)
|↑ 6-fold (3.5, 18.3X)
↑ 181-fold (ND)
|Sildenafil||100, single dose||500 twice daily, 8 d||28||↑ 11-fold||↑ 4-fold||ND|
|Sulfamethoxazole3||800, single dose||500 q12h, 12 d||15||↓ 20% (16, 23%)||↔||ND|
|Tadalafil||20 mg, single dose||200 mg q12h||↑ 124%||↔||ND|
|Theophylline||3 mg/kg q8h, 15 d||500 q12h, 10 d||13, 11*||↓ 43% (42, 45%)||↓ 32% (29, 34%)||↓ 57% (55, 59%)|
|Trazodone||50 mg, single dose||200 mg q12h, 4 doses||10||↑ 2.4-fold||↑ 34%|
|Trimethoprim3||160, single dose||500 q12h, 12 d||15||↑ 20% (3, 43%)||↔||ND|
|Vardenafil||5 mg||600 q12h||↑ 49-fold||↑ 13-fold||ND|
|Voriconazole||400 q12h, 1 d; then 200 q12h, 8 d||400 q12h, 9 d||↓ 82%||↓ 66%|
|400 q12h, 1 d; then 200 q12h, 8 d||100 q12h, 9 d||↓ 39%||↓ 24%|
|5, single dose||400 q12h, 12d||12||
↑ 9% (-17, 44%)4
↓ 33% (-38, -27%)4
↓ 9% (-16, -2%)4
|Zidovudine||200 q8h, 4 d||300 q6h, 4 d||9||↓ 25% (15, 34%)||↓ 27% (4, 45%)||ND|
Ritonavir is a peptidomimetic inhibitor of the HIV-1 protease. Inhibition of HIV protease renders the enzyme incapable of processing the gag-pol polyprotein precursor which leads to production of non-infectious immature HIV-1 particles.
The activity of ritonavir was assessed in acutely infected lymphoblastoid cell lines and in peripheral blood lymphocytes. The concentration of drug that inhibits 50% (EC50) value of viral replication ranged from 3.8 to 153 nM depending upon the HIV-1 isolate and the cells employed. The average EC50 for low passage clinical isolates was 22 nM (n = 13). In MT4 cells, ritonavir demonstrated additive effects against HIV-1 in combination with either didanosine (ddI) or zidovudine (ZDV). Studies which measured cytotoxicity of ritonavir on several cell lines showed that greater than 20 µM was required to inhibit cellular growth by 50% resulting in a cell culture therapeutic index of at least 1,000.
HIV-1 isolates with reduced susceptibility to ritonavir have been selected in cell culture. Genotypic analysis of these isolates showed mutations in the HIV-1 protease gene encoding at amino acid substitutions I84V, V82F, A71V, and M46I. Phenotypic (n = 18) and genotypic (n = 48) changes in HIV-1 isolates from selected patients treated with ritonavir were monitored in phase I/II trials over a period of 3 to 32 weeks. Substitutions associated with the HIV-1 viral protease in isolates obtained from 43 patients appeared to occur in a stepwise and ordered fashion; in sequence, these substitutions were position V82A/F/T/S, I54V, A71V/T, and I36L, followed by combinations of substitutions at an additional 5 specific amino acid positions (M46I/L, K20R, I84V, L33F and L90M). Of 18 patients for whom both phenotypic and genotypic analysis were performed on free virus isolated from plasma, 12 showed reduced susceptibility to ritonavir in cell culture. All 18 patients possessed one or more substitutions in the viral protease gene. The V82A/F substitution appeared to be necessary but not sufficient to confer phenotypic resistance. Phenotypic resistance was defined as a greater than or equal to 5-fold decrease in viral sensitivity in cell culture from baseline.
Among protease inhibitors variable cross-resistance has been recognized. Serial HIV-1 isolates obtained from six patients during ritonavir therapy showed a decrease in ritonavir susceptibility in cell culture but did not demonstrate a concordant decrease in susceptibility to saquinavir in cell culture when compared to matched baseline isolates. However, isolates from two of these patients demonstrated decreased susceptibility to indinavir in cell culture (8-fold). Isolates from 5 patients were also tested for cross-resistance to amprenavir and nelfinavir; isolates from 3 patients had a decrease in susceptibility to nelfinavir (6- to 14-fold), and none to amprenavir. Cross-resistance between ritonavir and reverse transcriptase inhibitors is unlikely because of the different enzyme targets involved. One ZDV-resistant HIV-1 isolate tested in cell culture retained full susceptibility to ritonavir.
Carcinogenicity studies in mice and rats have been carried out on ritonavir. In male mice, at levels of 50, 100 or 200 mg per kg per day, there was a dose dependent increase in the incidence of both adenomas and combined adenomas and carcinomas in the liver. Based on AUC measurements, the exposure at the high dose was approximately 0.3-fold for males that of the exposure in humans with the recommended therapeutic dose (600 mg twice-daily). There were no carcinogenic effects seen in females at the dosages tested. The exposure at the high dose was approximately 0.6-fold for the females that of the exposure in humans. In rats dosed at levels of 7, 15 or 30 mg per kg per day there were no carcinogenic effects. In this study, the exposure at the high dose was approximately 6% that of the exposure in humans with the recommended therapeutic dose. Based on the exposures achieved in the animal studies, the significance of the observed effects is not known.
Ritonavir was found to be negative for mutagenic or clastogenic activity in a battery of in vitro and in vivo assays including the Ames bacterial reverse mutation assay using S. typhimurium and E. coli, the mouse lymphoma assay, the mouse micronucleus test and chromosomal aberration assays in human lymphocytes.
Ritonavir produced no effects on fertility in rats at drug exposures approximately 40% (male) and 60% (female) of that achieved with the proposed therapeutic dose. Higher dosages were not feasible due to hepatic toxicity.
Study 247 was a randomized, double-blind trial (with open-label follow-up) conducted in HIV-1 infected patients with at least nine months of prior antiretroviral therapy and baseline CD4 cell counts less than or equal to 100 cells per µL. NORVIR 600 mg twice-daily or placebo was added to each patient's baseline antiretroviral therapy regimen, which could have consisted of up to two approved antiretroviral agents. The study accrued 1090 patients, with mean baseline CD4 cell count at study entry of 32 cells per µL. After the clinical benefit of NORVIR therapy was demonstrated, all patients were eligible to switch to open-label NORVIR for the duration of the follow-up period. Median duration of double-blind therapy with NORVIR and placebo was 6 months. The median duration of follow-up through the end of the open-label phase was 13.5 months for patients randomized to NORVIR and 14 months for patients randomized to placebo.
The cumulative incidence of clinical disease progression or death during the double-blind phase of Study 247 was 26% (140/543) for patients initially randomized to NORVIR compared to 42% (229/547) for patients initially randomized to placebo. This difference in rates was statistically significant.
Cumulative mortality through the end of the open-label follow-up phase for patients enrolled in Study 247 was 18% (99/543) for patients initially randomized to NORVIR compared to 26% (142/547) for patients initially randomized to placebo. This difference in rates was statistically significant. However, since the analysis at the end of the open-label phase includes patients in the placebo arm who were switched from placebo to NORVIR therapy, the survival benefit of NORVIR cannot be precisely estimated.
During the double-blind phase of Study 247, CD4 cell counts increases from baseline for patients randomized to NORVIR at Week 2 and Week 4 were observed. From Week 4 and through Week 24, mean CD4 cell counts for patients randomized to NORVIR appeared to plateau. In contrast, there was no apparent change in mean CD4 cell counts for patients randomized to placebo at any visit between baseline and Week 24 of the double-blind phase of Study 247.
In Study 245, 356 antiretroviral-naive HIV-1 infected patients (mean baseline CD4 = 364 cells/µL) were randomized to receive either NORVIR 600 mg twice-daily, zidovudine 200 mg three-times-daily, or a combination of these drugs.
During the double-blind phase of study 245, greater mean CD4 cell count increases were observed from baseline to Week 12 in the NORVIR-containing arms compared to the zidovudine arms. Mean CD4 cell count changes subsequently appeared to plateau through Week 24 in the NORVIR arm, whereas mean CD4 cell counts gradually diminished through Week 24 in the zidovudine and NORVIR plus zidovudine arms.
Greater mean reductions in plasma HIV-1 RNA levels were observed from baseline to Week 2 for the NORVIR-containing arms compared to the zidovudine arm. After Week 2 and through Week 24, mean plasma HIV-1 RNA levels either remained stable in the NORVIR and zidovudine arms or gradually rebounded toward baseline in the NORVIR plus zidovudine arm.
- Sewester CS. Calculations. In: Drug Facts and Comparisons. St. Louis, MO: J.B. Lippincott Co; January, 1997:xix.
NORVIR (ritonavir) soft gelatin capsules are white capsules imprinted with the “a” logo, 100 and the code DS, available in the following package size:
Bottles of 120 capsules each (NDC 0074-6633-22).
Bottles of 30 capsules each (NDC 0074-6633-30).
Store NORVIR soft gelatin capsules in the refrigerator between 2°-8°C (36°-46°F) until dispensed. Refrigeration of NORVIR soft gelatin capsules by the patient is recommended, but not required if used within 30 days and stored below 25°C (77°F). Protect from light. Avoid exposure to excessive heat.
Product should be stored and dispensed in the original container.
Keep cap tightly closed.
Patients should remain under the care of a physician while using NORVIR. Patients should be advised to take NORVIR and other concomitant antiretroviral therapy every day as prescribed. NORVIR must always be used in combination with other antiretroviral drugs. Patients should not alter the dose or discontinue therapy without consulting with their doctor. If a dose of NORVIR is missed patients should take the dose as soon as possible and then return to their normal schedule. However, if a dose is skipped the patient should not double the next dose.
NORVIR is not a cure for HIV-1 infection and patients may continue to experience illnesses associated with HIV-1 infection, including opportunistic infections. Patients should remain under the care of a physician when using NORVIR.
- Do not share needles or other injection equipment.
- Do not share personal items that can have blood or body fluids on them, like toothbrushes and razor blades.
- Do not have any kind of sex without protection. Always practice safe sex by using a latex or polyurethane condom to lower the chance of sexual contact with semen, vaginal secretions, or blood.
- Do not breastfeed. We do not know if NORVIR can be passed to the baby through breast milk and whether it could harm the baby. Also, mothers with HIV-1 should not breastfeed because HIV-1 can be passed to the baby in the breast milk.
NORVIR may interact with some drugs; therefore, patients should be advised to report to their doctor the use of any other prescription, non-prescription medication or herbal products, particularly St. John's Wort.
Pre-existing liver disease including Hepatitis B or C can worsen with use of NORVIR. This can be seen as worsening of transaminase elevations or hepatic decompensation. Patients should be advised that their liver function tests will need to be monitored closely especially during the first several months of NORVIR treatment and that they should notify their healthcare provider if they develop the signs and symptoms of worsening liver disease including loss of appetite, abdominal pain, jaundice, and itchy skin.
Pancreatitis, including some fatalities, has been observed in patients receiving NORVIR therapy. Your patients should let you know of signs and symptoms (nausea, vomiting, and abdominal pain) that might be suggestive of pancreatitis.
Skin rashes ranging in severity from mild to Stevens-Johnson syndrome have been reported in patients receiving NORVIR. Patients should be advised to contact their healthcare provider if they develop a rash while taking NORVIR. The healthcare provider will determine if treatment should be continued or an alternative antiretroviral regimen used.
NORVIR may produce changes in the electrocardiogram (e.g., PR prolongation). Patients should consult their physician if they experience symptoms such as dizziness, lightheadedness, abnormal heart rhythm or loss of consciousness.
New onset of diabetes or exacerbation of pre-existing diabetes mellitus, and hyperglycemia have been reported. Patients should be advised to notify their healthcare provider if they develop the signs and symptoms of diabetes mellitus including frequent urination, excessive thirst, extreme hunger or unusual weight loss and/or an increased blood sugar while on NORVIR as they may require a change in their diabetes treatment or new treatment.
If they are receiving avanafil, sildenafil, tadalafil, or vardenafil for the treatment of erectile dysfunction, they may be at an increased risk of associated adverse reactions including hypotension, visual changes, and sustained erection, and should promptly report any symptoms to their doctor. They should seek medical assistance immediately if they develop a sustained penile erection lasting more than 4 hours while taking NORVIR and a PDE5 Inhibitor such as Stendra®, Viagra®, Cialis® or Levitra®. If they are currently using or planning to use avanafil or tadalafil (for the treatment of pulmonary arterial hypertension) they should ask their doctor about potential adverse reactions these medications may cause when taken with NORVIR. The doctor may choose not to keep them on avanafil, or may adjust the dose of tadalafil while initiating treatment with NORVIR. Concomitant use of Revatio® (sildenafil) with NORVIR is contraindicated in patients with pulmonary arterial hypertension (PAH).
Read this Patient Information before you start taking NORVIR and each time you get a refill. There may be new information. This information does not take the place of talking to your doctor about your medical condition or your treatment.
- NORVIR can interact with other medicines and cause serious side effects. It is important to know the medicines that should not be taken with NORVIR. See the section “Who should not take NORVIR?”
NORVIR is a prescription anti-HIV medicine used with other anti-HIV medicines to treat people with human immunodeficiency virus (HIV) infection. NORVIR is a type of anti-HIV medicine called a protease inhibitor. HIV is the virus that causes AIDS (Acquired Immune Deficiency Syndrome).
When used with other HIV medicines, NORVIR may reduce the amount of HIV in your blood (called “viral load”). NORVIR may also help to increase the number of CD4 (T) cells in your blood which help fight off other infections. Reducing the amount of HIV and increasing the CD4 (T) cell count may improve your immune system. This may reduce your risk of death or infections that can happen when your immune system is weak (opportunistic infections).
NORVIR does not cure HIV infection or AIDS and you may continue to experience illnesses associated with HIV-1 infection, including opportunistic infections. You should remain under the care of a doctor when using NORVIR.
- Do not share needles or other injection equipment.
- Do not share personal items that can have blood or body fluids on them, like toothbrushes and razor blades.
- Do not have any kind of sex without protection. Always practice safe sex by using a latex or polyurethane condom to lower the chance of sexual contact with semen, vaginal secretions, or blood.
- alfuzosin (Uroxatral)
- amiodarone (Cordarone, Nexterone, Pacerone), flecainide (Tambocor), propafenone (Rhythmol) or quinidine (Nuedext, Quinaglute, Cardioquin, Quinidex, and others)
- voriconazole (VFend) if NORVIR dose is 400 mg every 12 hours or greater
- dihydroergotamine (D.H.E. 45, Embolex, Migranal), ergonovine, ergotamine (Cafergot,Ergomar) methylergonovine (Methergine)
- cisapride (Propulsid)
- St. John’s Wort (Hypericum perforatum)
- the cholesterol lowering medicines lovastatin (Mevacor, Altoprev, Advicor) or simvastatin (Zocor, Simcor, Vytorin)
- pimozide (Orap)
- sildenafil (Revatio) only when used for the treatment of pulmonary arterial hypertension
- oral midazolam or triazolam (Halcion)
- have liver problems, including Hepatitis B or Hepatitis C.
- have heart problems.
- have high blood sugar (diabetes).
- have bleeding problems or hemophilia.
- are pregnant or plan to become pregnant. It is not known if NORVIR can harm your unborn baby.
Pregnancy Registry: There is a pregnancy registry for women who take antiviral medicines during pregnancy. The purpose of the registry is to collect information about the health of you and your baby. Talk to your doctor about how you can take part in this registry.
- are breastfeeding. Do not breastfeed if you take NORVIR.
- You should not breastfeed if you have HIV-1 because of the risk of passing HIV-1 to your baby.
- It is not known if NORVIR passes into your breast milk
- Talk to your doctor about the best way to feed your baby.
Tell your doctor about all the medicines you take including prescription and nonprescription medicines, vitamins, and herbal supplements. Taking NORVIR and certain other medicines may affect each other causing serious side effects. NORVIR may affect the way other medicines work and other medicines may affect how NORVIR works.
- medicine to treat HIV
- estrogen-based contraceptives (birth control). NORVIR might reduce the effectiveness of estrogen-based contraceptives. You must take additional precautions for birth control such as a condom.
- medicine for pain such as tramadol (Ryzolt, Ultracet, Conzip, Ultram), propoxyphene, or meperidine (Demerol)
- medicine to treat alcohol abuse such as disulfiram (Antabuse)
- medicine for your heart such as disopyramide (Norpace), lidocaine (Xylocaine Viscous), mexiletine, digoxin (Lanoxin), nifedipine (Procardia, Adalat, Afeditab CR), diltiazem (Cardizem, Dilacor, Cartia, Diltzac, Dilt, Taztia, Tiazac) or verapamil (Calan, Covera, Isoptin, Tarka, Verelan)
- medicines for panic disorder or anxiety such as buspirone, clorazepate, diazepam, estazolam, flurazepam, and zolpidem
- medicine for cancer such as dasatinib (Sprycel), nilotinib (Tasigna) vincristine, or vinblastine
- warfarin (Coumadin, Jantoven), rivaroxaban (Xarelto)
- medicine for seizures such as carbamazepine (Carbatrol, Equetro, Tegretol, Epitol), clonazepam (Klonopin), ethosuximide (Zarontin, Ethosuximide) , divalproex (Depakote, Divalproex Sodium), lamotrigine (Lamictal) or phenytoin (Dilantin, Phenytek)
- medicine for depression such as nefazodone, bupropion (Wellbutrin, Aplenzin, Zyban), desipramine (Norpramin) or trazadone, fluoxetine (Prozac), paroxetine (Paxil), amitriptyline, or nortriptyline
- medicine for nausea and vomiting such as dronabinol (Marinol) or perphenazine
- medicine for fungal infections such as ketoconazole (Nizoral), itraconazole (Sporanox, Onmel) or voriconazole (VFend)
- colchicine (Colcrys, Col-Probenecid, Probenecid and Colchine)
- medicine for infections such as clarithromycin (Prevpac, Biaxin), rifabutin (Mycobutin), rifampin (Rimactane, Rifadin, Rifater, Rifamate), atovaquone (Mepron, Malarone), quinine (Qualaquin) or metronidazole (Flagyl, Helidac, Metrocream)
- medicine used to treat blood pressure, a heart attack, heart failure, or to lower pressure in the eye such as metoprolol (Lopressor, Toprol-XL), timolol (Cosopt, Betimol, Timoptic, Isatolol, Combigan)
- medicine for lung disease such as theophylline and salmeterol (Serevent)
- bosentan (Tracleer)
- medicine to prevent organ transplant failure such as cyclosporine (Gengraf, Sandimmune, Neoral), tacrolimus (Prograf,) sirolimus (Rapamune)
- steroids such as dexamethasone, fluticasone (Advair Diskus, Veramyst, Flovent, Flonase), budesonide (Entocort EC, Pulmicort, Rhinocort), or prednisone
- a narcotic medicine such as methadone (Methadose, Dolophine Hydrochloride) or fentanyl (Abstral, Actiq, Fentora, Lazanda, Onsolis, Duragesic)
- medicine to treat schizophrenia such as risperidone (Risperdal) or thioridazine
- medicine to treat erectile dysfunction or pulmonary hypertension such as avanafil (Stendra), sildenafil (Viagra, Revatio), vardenafil (Levitra, Staxyn), tadalafil (Cialis, Adcirca). If you are taking avanafil (Stendra), your doctor may need to change it to a different medicine.
- midazolam by injection
- methamphetamine (Desoxyn)
- cholesterol lowering medicine such as atorvastatin (Lipitor) or rosuvasatin (Crestor)
This is not a complete list of medicines that you should tell your doctor that you are taking. Ask your doctor, provider or pharmacist if you are not sure if your medicine is one that is listed above.
Know the medicines you take. Keep a list of them to show your doctor or pharmacist when you get a new medicine. Do not start any new medicines while you are taking NORVIR without first talking with your doctor.
- Take NORVIR exactly as prescribed by your doctor.
- You should stay under a doctor's care when taking NORVIR. Do not change your dose of NORVIR or stop treatment without talking with your doctor first.
- If your child is taking NORVIR, your child’s doctor will decide the right dose based on your child's height and weight. Tell your doctor if your child’s weight changes. Your child should take NORVIR with food.
- Take NORVIR with food if possible.
- Do not run out of NORVIR. Get your NORVIR prescription refilled from you doctor or pharmacy before you run out.
- If you miss a dose of NORVIR, take it as soon as possible and then take your next scheduled dose at its regular time. If it is almost time for your next dose, wait and take the next dose at the regular time. Do not double the next dose.
- If you take too much NORVIR, call your local poison control center or go to the nearest hospital emergency room right away.
- See “What is the most important information I should know about NORVIR?”
Liver disease. Some people taking NORVIR in combination with other anti-HIV medicines have developed liver problems which may be life-threatening. Your doctor should do regular blood tests during your combination treatment with NORVIR. If you have chronic hepatitis B or C infection, your doctor should check your blood tests more often because you have an increased chance of developing liver problems. Tell your doctor if you have any of the below signs and symptoms of liver problems:
- loss of appetite
- pain or tenderness on your right side below your ribs
- yellowing of your skin or whites of your eyes
- itchy skin
Swelling of your pancreas (Pancreatitis). NORVIR can cause serious pancreas problems, which may lead to death. Tell your doctor right away if you have signs or symptoms of pancreatitis such as:
- stomach (abdomen) pain
Allergic Reactions. Sometimes these allergic reactions can become severe and require treatment in a hospital. You should call your doctor right away if you develop a rash. Stop taking NORVIR and get medical help right away if you have any of the following symptoms of a severe allergic reaction:
- trouble breathing
- dizziness or fainting
- throat tightness or hoarseness
- fast heartbeat or pounding in your chest (tachycardia)
- swelling of your face, lips or tongue
- muscle or joint pain
- blisters or skin lesions
- mouth sores or ulcers
Changes in the electrical activity of your heart called PR prolongation. PR prolongation can cause irregular heartbeats. Tell your doctor right away if you have symptoms such as:
- feeling faint or passing out
- abnormal heart beat
- Increase in some fats (cholesterol and triglyceride levels) in your blood. Treatment with NORVIR may increase your blood levels of cholesterol and triglycerides. Your doctor should do blood tests before you start your treatment with NORVIR and regularly to check for an increase in your cholesterol and triglycerides levels.
- Diabetes and high blood sugar (hyperglycemia). Some people who take protease inhibitors including NORVIR can get high blood sugar, develop diabetes, or their diabetes can get worse. Tell your doctor if you notice an increase in thirst or urinate often while taking NORVIR.
- Changes in your immune system (Immune reconstitution syndrome) can happen when you start taking HIV medicines. Your immune system may get stronger and begin to fight infections that have been hidden in your body for a long time. Call your doctor right away if you start having new symptoms after starting your HIV medicine.
- Change in body fat. These changes can happen in people who take antiretroviral therapy. The changes may include an increase amount of fat in the upper back and neck (“buffalo hump”), breast, and around the back and stomach area. Loss of fat from the legs, arms, and face may also happen. The exact cause and long-term health effects of these conditions are not known.
- Increased bleeding for hemophiliacs. Some people with hemophilia have increased bleeding with protease inhibitors including NORVIR.
- upper and lower stomach (abdomen) pain
- tingling feeling or numbness in hands or feet or around the lips
- feeling weak or tired
- Protect NORVIR soft gelatin capsules from light.
- Keep NORVIR soft gelatin capsules away from heat.
- Store NORVIR soft gelatin capsules tightly closed in the original container.
- Use NORVIR soft gelatin capsules by the expiration date on the bottle.
Medicines are sometimes prescribed for purposes other than those listed in a Patient Information Leaflet. Do not use this medicine for a condition for which it was not prescribed. Do not share this medicine with other people.
This leaflet summarizes the most important information about NORVIR. If you would like more information, talk to your doctor. You can ask your doctor or pharmacist for information about NORVIR that is written for healthcare professionals.
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