2.1 Important Dosage and Administration Information

Buprenorphine transdermal system should be prescribed only by healthcare professionals who are knowledgeable in the use of potent opioids for the management of chronic pain.

Buprenorphine transdermal system doses of 10, 15, and 20 mcg/hour are only for use in patients who are opioid experienced and in whom tolerance to an opioid of comparable potency has been established. Patients who are opioid-experienced are those receiving, for one week or longer, daily opioid doses up to 80 mg/day of oral morphine or an equianalgesic dose of another opioid.

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Use the lowest effective dosage for the shortest duration consistent with individual patients treatment goals [see Warnings and Precautions (5)].

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Initiate the dosing regimen for each patient individually, taking into account the patient's severity of pain, patient response, prior analgesic treatment experience, and risk factors for addiction, abuse, and misuse [see Warnings and Precautions (5.1)].

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Monitor patients closely for respiratory depression, especially within the first 24-72 hours of initiating therapy and following dosage increases with buprenorphine transdermal system [see Warnings and Precautions (5.2)].

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Instruct patients not to use buprenorphine transdermal system if the pouch seal is broken or the patch is cut, damaged, or changed in any way and not to cut buprenorphine transdermal system.

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Instruct patients to avoid exposing buprenorphine transdermal system to external heat sources, hot water, or prolonged direct sunlight [see Warnings and Precautions (5.14)].

Buprenorphine transdermal system is for transdermal use (on intact skin) only. Each buprenorphine transdermal system patch is intended to be worn for 7 days.

2.2 Initial Dosage

Use of Buprenorphine Transdermal System as the First Opioid Analgesic (opioid-naive patients)

Initiate treatment with buprenorphine transdermal system with a 5 mcg/hour patch.

Conversion from Other Opioids to Buprenorphine Transdermal System

Discontinue all other around-the-clock opioid drugs when buprenorphine transdermal system therapy is initiated.

There is a potential for buprenorphine to precipitate withdrawal in patients who are already on opioids.

Prior Total Daily Dose of Opioid Less than 30 mg of Oral Morphine Equivalents per Day: Initiate treatment with buprenorphine transdermal system 5 mcg/hour at the next dosing interval (see Table 1 below, middle column).

Prior Total Daily Dose of Opioid Between 30 mg to 80 mg of Oral Morphine Equivalents per Day:

Taper the patient’s current around-the-clock opioids for up to 7 days to no more than 30 mg of morphine or equivalent per day before beginning treatment with buprenorphine transdermal system. Then initiate treatment with buprenorphine transdermal system 10 mcg/hour at the next dosing interval (see Table 1 below, right column). Patients may use short-acting analgesics as needed until analgesic efficacy with buprenorphine transdermal system is attained.

Prior Total Daily Dose of Opioid Greater than 80 mg of Oral Morphine Equivalents per Day: Buprenorphine transdermal system 20 mcg/hour may not provide adequate analgesia for patients requiring greater than 80 mg/day oral morphine equivalents. Consider the use of an alternate analgesic.

Conversion from Methadone to Buprenorphine Transdermal System

Close monitoring is of particular importance when converting from methadone to other opioid agonists. The ratio between methadone and other opioid agonists may vary widely as a function of previous dose exposure. Methadone has a long half-life and can accumulate in the plasma.

2.3 Titration and Maintenance of Therapy

Individually titrate buprenorphine transdermal system to a dose that provides adequate analgesia and minimizes adverse reactions. Continually reevaluate patients receiving buprenorphine transdermal system to assess the maintenance of pain control and the relative incidence of adverse reactions, as well as monitoring for the development of addiction, abuse, or misuse [see Warnings and Precautions (5.1)]. Frequent communication is important among the prescriber, other members of healthcare team, the patient, and the caregiver/family during periods of changing analgesic requirements, including initial titration. During chronic therapy, periodically reassess the continued need for opioid analgesics.

The minimum buprenorphine transdermal system titration interval is 72 hours, based on the pharmacokinetic profile and time to reach steady state levels [see Clinical Pharmacology (12.3)].

The maximum buprenorphine transdermal system dose is 20 mcg/hour. Do not exceed a dose of one 20 mcg/hour buprenorphine transdermal system due to the risk of QTc interval prolongation. In a clinical trial, buprenorphine transdermal system 40 mcg/hour (given as two buprenorphine transdermal system 20 mcg/hour systems) resulted in prolongation of the QTc interval [see Warnings and Precautions (5.7) and Clinical Pharmacology (12.2)].

Patients who experience breakthrough pain may require dosage adjustment increase of buprenorphine transdermal system, or may need rescue medication with an appropriate dose of an immediate-release analgesic. If the level of pain increases after dose stabilization, attempt to identify the source of increased pain before increasing the buprenorphine transdermal system dose.

Because steady-state plasma concentrations are achieved within 72 hours, buprenorphine transdermal system dosage may be adjusted every 3 days. Dose adjustments may be made in 5 mcg/hour, or 10 mcg/hour increments by using no more than two patches of the 5 mcg/hour, or 10 mcg/hour system(s). The total dose from both patches should not exceed 20 mcg/hour. For the use of two patches, instruct patients to remove their current patch, and apply the two new patches at the same time, adjacent to one another at a different application site [see Dosage and Administration (2.6)].

If unacceptable opioid-related adverse reactions are observed, consider reducing the dosage. Adjust the dosage to obtain an appropriate balance between the management of pain and opioid-related adverse reactions.

2.4 Discontinuation of Buprenorphine Transdermal System

When the patient no longer requires therapy with buprenorphine transdermal system, use a gradual downward titration of the dose every 7 days, while monitoring carefully for signs and symptoms of withdrawal. If the patient develops these signs or symptoms, consider introduction of an appropriate immediate-release opioid medication. Do not abruptly discontinue buprenorphine transdermal system.

2.5 Patients with Hepatic Impairment

Buprenorphine transdermal system has not been evaluated in patients with severe hepatic impairment. As buprenorphine transdermal system is only intended for 7-day application, consider use of an alternate analgesic that may permit more flexibility with the dosing in patients with severe hepatic impairment [see Warnings and Precautions (5.11), Use in Specific Populations (8.6), and Clinical Pharmacology (12.3)].

2.6 Administration of Buprenorphine Transdermal System

Instruct patients to apply immediately after removal from the individually sealed pouch. Instruct patients not to use buprenorphine transdermal system if the pouch seal is broken or the patch is cut, damaged, or changed in any way. See the Instructions for Use for step-by-step instructions for applying buprenorphine transdermal system.

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Apply buprenorphine transdermal system to the upper outer arm, upper chest, upper back or the side of the chest. These 4 sites (each present on both sides of the body) provide 8 possible application sites. Rotate buprenorphine transdermal system among the 8 described skin sites. After buprenorphine transdermal system removal, wait a minimum of 21 days before reapplying to the same skin site [see Clinical Pharmacology (12.3)].

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Apply buprenorphine transdermal system to a hairless or nearly hairless skin site. If none are available, the hair at the site should be clipped, not shaven. Do not apply buprenorphine transdermal system to irritated skin. If the application site must be cleaned, clean the site with water only. Do not use soaps, alcohol, oils, lotions, or abrasive devices. Allow the skin to dry before applying buprenorphine transdermal system.

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Incidental exposure of the buprenorphine transdermal system patch to water, such as while bathing or showering is acceptable based on experience during clinical studies.

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If problems with adhesion of buprenorphine transdermal system occur, the edges may be taped with first aid tape. If problems with lack of adhesion continue, the patch may be covered with waterproof or semipermeable adhesive dressings suitable for 7 days of wear.

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If buprenorphine transdermal system falls off during the 7-day dosing interval, dispose of the transdermal system properly and place a new buprenorphine transdermal system patch on at a different skin site.

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When changing the system, instruct patients to remove buprenorphine transdermal system and dispose of it properly [see Dosage and Administration (2.7)].

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If the buprenorphine-containing adhesive matrix accidentally contacts the skin, instruct patients or caregivers to wash the area with water and not to use soap, alcohol, or other solvents to remove the adhesive because they may enhance the absorption of the drug.

2.7 Disposal Instructions

Patients should refer to the Instructions for Use for proper disposal of buprenorphine transdermal system. Dispose of used and unused patches by following the instructions on the Patch-Disposal Unit that is packaged with the buprenorphine transdermal system patches.

Alternatively, patients can dispose of used patches by folding the adhesive side of the patch to itself, then flushing the patch down the toilet immediately upon removal. Unused patches should be removed from their pouches, the protective liners removed, the patches folded so that the adhesive side of the patch adheres to itself, and immediately flushed down the toilet.

Patients should dispose of any patches remaining from a prescription as soon as they are no longer needed.

5.1 Addiction, Abuse, and Misuse

Buprenorphine transdermal system contains buprenorphine, a Schedule III controlled substance. As an opioid, buprenorphine transdermal system exposes users to the risks of addiction, abuse, and misuse [see Drug Abuse and Dependence (9)]. Because extended-release products such as buprenorphine transdermal system deliver the opioid over an extended period of time, there is a greater risk for overdose and death, due to the larger amount of buprenorphine present.

Although the risk of addiction in any individual is unknown, it can occur in patients appropriately prescribed buprenorphine transdermal system. Addiction can occur at recommended doses and if the drug is misused or abused.

Assess each patient’s risk for opioid addiction, abuse, or misuse prior to prescribing buprenorphine transdermal system, and monitor all patients receiving buprenorphine transdermal system for the development of these behaviors and conditions. Risks are increased in patients with a personal or family history of substance abuse (including drug or alcohol abuse or addiction) or mental illness (e.g., major depression). The potential for these risks should not, however, prevent the proper management of pain in any given patient. Patients at increased risk may be prescribed opioids such as buprenorphine transdermal system, but use in such patients necessitates intensive counseling about the risks and proper use of buprenorphine transdermal system, along with intensive monitoring for signs of addiction, abuse, or misuse.

Abuse or misuse of buprenorphine transdermal system by placing it in the mouth, chewing it, swallowing it, or using it in ways other than indicated may cause choking, overdose and death [see Overdosage (10)].

Opioids are sought by drug abusers and people with addiction disorders and are subject to criminal diversion. Consider these risks when prescribing or dispensing buprenorphine transdermal system. Strategies to reduce these risks include prescribing the drug in the smallest appropriate quantity and advising the patient on the proper disposal of unused drug [see Patient Counseling Information (17)]. Contact local state professional licensing board or state controlled substances authority for information on how to prevent and detect abuse or diversion of this product.

5.2 Life-Threatening Respiratory Depression

Serious, life-threatening, or fatal respiratory depression has been reported with the use of opioids, even when used as recommended. Respiratory depression, if not immediately recognized and treated, may lead to respiratory arrest and death. Management of respiratory depression may include close observation, supportive measures, and use of opioid antagonists, depending on the patient’s clinical status [see Overdosage (10)]. Carbon dioxide (CO2) retention from opioid-induced respiratory depression can exacerbate the sedating effects of opioids.

While serious, life-threatening, or fatal respiratory depression can occur at any time during the use of buprenorphine transdermal system, the risk is greatest during the initiation of therapy or following a dosage increase. Monitor patients closely for respiratory depression, especially within the first 24-72 hours of initiating therapy with buprenorphine transdermal system and following dosage increases of buprenorphine transdermal system.

To reduce the risk of respiratory depression, proper dosing and titration of buprenorphine transdermal system are essential [see Dosage and Administration (2)]. Overestimating the buprenorphine transdermal system dosage when converting patients from another opioid product can result in fatal overdose with the first dose.

Accidental exposure to buprenorphine transdermal system, especially in children, can result in respiratory depression and death due to an overdose of buprenorphine.

5.3 Neonatal Opioid Withdrawal Syndrome

Prolonged use of buprenorphine transdermal system during pregnancy can result in withdrawal in the neonate. Neonatal opioid withdrawal syndrome, unlike opioid withdrawal syndrome in adults, may be life-threatening if not recognized and treated, and requires management according to protocols developed by neonatology experts. Observe newborns for signs of neonatal opioid withdrawal syndrome and manage accordingly. Advise pregnant women using opioids for a prolonged period of the risk of neonatal opioid withdrawal syndrome and ensure that appropriate treatment will be available [see Use in Specific Populations (8.1), Patients Counseling Information (17)].

5.4 Risks from Concomitant Use with Benzodiazepines or Other CNS Depressants

Profound sedation, respiratory depression, coma, and death may result from the concomitant use of buprenorphine transdermal system with benzodiazepines or other CNS depressants (e.g., non-benzodiazepine sedatives/hypnotics, anxiolytics, tranquilizers, muscle relaxants, general anesthetics, antipsychotics, other opioids, alcohol). Because of these risks, reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate.

Observational studies have demonstrated that concomitant use of opioid analgesics and benzodiazepines increases the risk of drug-related mortality compared to use of opioid analgesics alone. Because of similar pharmacological properties, it is reasonable to expect similar risk with the concomitant use of other CNS depressant drugs with opioid analgesics [see Drug Interactions (7)].

If the decision is made to prescribe a benzodiazepine or other CNS depressant concomitantly with an opioid analgesic, prescribe the lowest effective dosages and minimum durations of concomitant use. In patients already receiving an opioid analgesic, prescribe a lower initial dose of the benzodiazepine or other CNS depressant than indicated in the absence of an opioid, and titrate based on clinical response. If an opioid analgesic is initiated in a patient already taking a benzodiazepine or other CNS depressant, prescribe a lower initial dose of the opioid analgesic, and titrate based on clinical response. Follow patients closely for signs and symptoms of respiratory depression and sedation.

Advise both patients and caregivers about the risks of respiratory depression and sedation when buprenorphine transdermal system is used with benzodiazepines or other CNS depressants (including alcohol and illicit drugs). Advise patients not to drive or operate heavy machinery until the effects of concomitant use of the benzodiazepine or other CNS depressant have been determined. Screen patients for risk of substance use disorders, including opioid abuse and misuse, and warn them of the risk for overdose and death associated with the use of additional CNS depressants including alcohol and illicit drugs [see Drug Interactions (7), Patient Counseling Information (17)].

5.5 Life-Threatening Respiratory Depression in Patients with Chronic Pulmonary Disease or in Elderly, Cachectic, or Debilitated Patients

The use of buprenorphine transdermal system in patients with acute or severe bronchial asthma in an unmonitored setting or in the absence of resuscitative equipment is contraindicated.

Patients with Chronic Pulmonary Disease: Buprenorphine transdermal system -treated patients with significant chronic obstructive pulmonary disease or cor pulmonale, and those with a substantially decreased respiratory reserve, hypoxia, hypercapnia, or pre-existing respiratory depression are at increased risk of decreased respiratory drive including apnea, even at recommended dosages of buprenorphine transdermal system [see Warnings and Precautions (5.2)].

Elderly, Cachectic, or Debilitated Patients: Life-threatening respiratory depression is more likely to occur in elderly, cachectic, or debilitated patients because they may have altered pharmacokinetics or altered clearance compared to younger, healthier patients [see Warnings and Precautions (5.2)].

Monitor such patients closely, particularly when initiating and titrating buprenorphine transdermal system and when buprenorphine transdermal system is given concomitantly with other drugs that depress respiration [see Warnings and Precautions (5.2, 5.4)]. Alternatively, consider the use of non-opioid analgesics in these patients.

5.6 Adrenal Insufficiency

Cases of adrenal insufficiency have been reported with opioid use, more often following greater than one month of use. Presentation of adrenal insufficiency may include non-specific symptoms and signs including nausea, vomiting, anorexia, fatigue, weakness, dizziness, and low blood pressure. If adrenal insufficiency is suspected, confirm the diagnosis with diagnostic testing as soon as possible. If adrenal insufficiency is diagnosed, treat with physiologic replacement doses of corticosteroids. Wean the patient off of the opioid to allow adrenal function to recover and continue corticosteroid treatment until adrenal function recovers. Other opioids may be tried as some cases reported use of a different opioid without recurrence of adrenal insufficiency. The information available does not identify any particular opioids as being more likely to be associated with adrenal insufficiency.

5.7 QTc Prolongation

A positive-controlled study of the effects of buprenorphine transdermal system on the QTc interval in healthy subjects demonstrated no clinically meaningful effect at a buprenorphine transdermal system dose of 10 mcg/hour; however, a buprenorphine transdermal system dose of 40 mcg/hour (given as two buprenorphine transdermal system 20 mcg/hour systems) was observed to prolong the QTc interval.

Consider these observations in clinical decisions when prescribing buprenorphine transdermal system to patients with hypokalemia or clinically unstable cardiac disease, including unstable atrial fibrillation, symptomatic bradycardia, unstable congestive heart failure, or active myocardial ischemia. Avoid the use of buprenorphine transdermal system in patients with a history of Long QT Syndrome or an immediate family member with this condition, or those taking Class IA antiarrhythmic medications (e.g., quinidine, procainamide, disopyramide) or Class III antiarrhythmic medications (e.g., sotalol, amiodarone, dofetilide), or other medications that prolong the QTc interval [see Dosage and Administration (2.3), Adverse Reactions (6.1), Clinical Pharmacology (12.2)].

5.8 Severe Hypotension

Buprenorphine transdermal system may cause severe hypotension including orthostatic hypotension and syncope in ambulatory patients. There is an increased risk in patients whose ability to maintain blood pressure has already been compromised by a reduced blood volume or concurrent administration of certain CNS depressant drugs (e.g., phenothiazines or general anesthetics) [see Drug Interactions (7)]. Monitor these patients for signs of hypotension after initiating or titrating the dosage of buprenorphine transdermal system. In patients with circulatory shock, buprenorphine transdermal system may cause vasodilation that can further reduce cardiac output and blood pressure. Avoid the use of buprenorphine transdermal system in patients with circulatory shock.

5.9 Risks of Use in Patients with Increased Intracranial Pressure, Brain Tumors, Head Injury or Impaired Consciousness

In patients who may be susceptible to the intracranial effects of CO2 retention (e.g., those with evidence of increased intracranial pressure or brain tumors), buprenorphine transdermal system may reduce respiratory drive, and the resultant CO2 retention can further increase intracranial pressure. Monitor such patients for signs of sedation and respiratory depression, particularly when initiating therapy with buprenorphine transdermal system.

Opioids may also obscure the clinical course in a patient with a head injury. Avoid the use of buprenorphine transdermal system in patients with impaired consciousness or coma.

5.10 Hepatotoxicity

Cases of cytolytic hepatitis and hepatitis with jaundice have been observed in individuals receiving sublingual buprenorphine for the treatment of opioid dependence, both in clinical trials and in post-marketing adverse event reports. The spectrum of abnormalities ranges from transient asymptomatic elevations in hepatic transaminases to case reports of hepatic failure, hepatic necrosis, hepatorenal syndrome, and hepatic encephalopathy. In many cases, the presence of pre-existing liver enzyme abnormalities, infection with hepatitis B or hepatitis C virus, concomitant usage of other potentially hepatotoxic drugs, and ongoing injection drug abuse may have played a causative or contributory role. For patients at increased risk of hepatotoxicity (e.g., patients with a history of excessive alcohol intake, intravenous drug abuse or liver disease), obtain baseline liver enzyme levels and monitor periodically and during treatment with buprenorphine transdermal system.

5.11 Application Site Skin Reactions

In rare cases, severe application site skin reactions with signs of marked inflammation including “burn,” “discharge,” and “vesicles” have occurred. Time of onset varies, ranging from days to months following the initiation of buprenorphine transdermal system treatment. Instruct patients to promptly report the development of severe application site reactions and discontinue therapy.

5.12 Anaphylactic/Allergic Reactions

Cases of acute and chronic hypersensitivity to buprenorphine have been reported both in clinical trials and in the post-marketing experience. The most common signs and symptoms include rashes, hives, and pruritus. Cases of bronchospasm, angioneurotic edema, and anaphylactic shock have been reported. A history of hypersensitivity to buprenorphine is a contraindication to the use of buprenorphine transdermal system.

5.13 Risks of Use with Application of External Heat

Advise patients and their caregivers to avoid exposing the buprenorphine transdermal system application site and surrounding area to direct external heat sources, such as heating pads or electric blankets, heat or tanning lamps, saunas, hot tubs, and heated water beds while wearing the system because an increase in absorption of buprenorphine may occur [see Clinical Pharmacology (12.3)]. Advise patients against exposure of the buprenorphine transdermal system application site and surrounding area to hot water or prolonged exposure to direct sunlight. There is a potential for temperature-dependent increases in buprenorphine released from the system resulting in possible overdose and death [see Patient Counseling Information (17)].

5.14 Risk of Use in Patients with Fever

Monitor patients wearing buprenorphine transdermal system who develop fever or increased core body temperature due to strenuous exertion for opioid side effects and adjust the buprenorphine transdermal system dose if signs of respiratory or central nervous system depression occur.

5.15 Risks of Use in Patients with Gastrointestinal Conditions

Buprenorphine transdermal system is contraindicated in patients with known or suspected gastrointestinal obstruction, including paralytic ileus.

The buprenorphine in buprenorphine transdermal system may cause spasm of the sphincter of Oddi. Opioids may cause increases in the serum amylase. Monitor patients with biliary tract disease, including acute pancreatitis, for worsening symptoms.

5.16 Increased Risk of Seizures in Patients with Seizure Disorders

The buprenorphine in buprenorphine transdermal system may increase the frequency of seizures in patients with seizure disorders, and may increase the risk of seizures in other clinical settings associated with seizures. Monitor patients with a history of seizure disorders for worsened seizure control during buprenorphine transdermal system therapy.

5.17 Risks of Driving and Operating Machinery

Buprenorphine transdermal system may impair the mental and physical abilities needed to perform potentially hazardous activities such as driving a car or operating machinery. Warn patients not to drive or operate dangerous machinery unless they are tolerant to the effects of buprenorphine transdermal system and know how they will react to the medication [see Patient Counseling Information (17)].

5.18 Use in Addiction Treatment

Buprenorphine transdermal system has not been studied and is not approved for use in the management of addictive disorders.

6.1 Clinical Trial Experience

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 practice.

A total of 5,415 patients were treated with buprenorphine transdermal system in controlled and open-label chronic pain clinical trials. Nine hundred twenty-four subjects were treated for approximately six months and 183 subjects were treated for approximately one year. The clinical trial population consisted of patients with persistent moderate to severe pain.

The most common serious adverse drug reactions (all <0.1%) occurring during clinical trials with buprenorphine transdermal system were: chest pain, abdominal pain, vomiting, dehydration, and hypertension/blood pressure increased.

The most common adverse events (≥ 2%) leading to discontinuation were: nausea, dizziness, vomiting, headache, and somnolence.

The most common adverse reactions (≥ 5%) reported by patients in clinical trials comparing buprenorphine transdermal system 10 or 20 mcg/hour to placebo are shown in Table 2, and comparing buprenorphine transdermal system 20 mcg/hour to buprenorphine transdermal system 5 mcg/hour are shown in Table 3 below:

The following table lists adverse reactions that were reported in at least 2.0% of patients in four placebo/active-controlled titration-to-effect trials.

The adverse reactions seen in controlled and open-label studies are presented below in the following manner: most common (≥ 5%), common (≥ 1% to < 5%), and less common (< 1%).

The most common adverse reactions (≥ 5%) reported by patients treated with buprenorphine transdermal system in the clinical trials were nausea, headache, application site pruritus, dizziness, constipation, somnolence, vomiting, application site erythema, dry mouth, and application site rash.

The common (≥ 1% to < 5%) adverse reactions reported by patients treated with buprenorphine transdermal system in the clinical trials organized by MedDRA (Medical Dictionary for Regulatory Activities) System Organ Class were:

Gastrointestinal disorders: diarrhea, dyspepsia, and upper abdominal pain

General disorders and administration site conditions: fatigue, peripheral edema, application site irritation, pain, pyrexia, chest pain, and asthenia

Infections and infestations: urinary tract infection, upper respiratory tract infection, nasopharyngitis, influenza, sinusitis, and bronchitis

Injury, poisoning and procedural complications: fall

Metabolism and nutrition disorders: anorexia

Musculoskeletal and connective tissue disorders: back pain, arthralgia, pain in extremity, muscle spasms, musculoskeletal pain, joint swelling, neck pain, and myalgia

Nervous system disorders: hypoesthesia, tremor, migraine, and paresthesia

Psychiatric disorders: insomnia, anxiety, and depression

Respiratory, thoracic and mediastinal disorders: dyspnea, pharyngolaryngeal pain, and cough

Skin and subcutaneous tissue disorders: pruritus, hyperhidrosis, rash, and generalized pruritus

Vascular disorders: hypertension

Other less common adverse reactions, including those known to occur with opioid treatment, that were seen in < 1% of the patients in the buprenorphine transdermal system trials include the following in alphabetical order:

Abdominal distention, abdominal pain, accidental injury, affect lability, agitation, alanine aminotransferase increased, angina pectoris, angioedema, apathy, application site dermatitis, asthma aggravated, bradycardia, chills, confusional state, contact dermatitis, coordination abnormal, dehydration, depersonalization, depressed level of consciousness, depressed mood, disorientation, disturbance in attention, diverticulitis, drug hypersensitivity, drug withdrawal syndrome, dry eye, dry skin, dysarthria, dysgeusia, dysphagia, euphoric mood, face edema, flatulence, flushing, gait disturbance, hallucination, hiccups, hot flush, hyperventilation, hypotension, hypoventilation, ileus, insomnia, libido decreased, loss of consciousness, malaise, memory impairment, mental impairment, mental status changes, miosis, muscle weakness, nervousness, nightmare, orthostatic hypotension, palpitations, psychotic disorder, respiration abnormal, respiratory depression, respiratory distress, respiratory failure, restlessness, rhinitis, sedation, sexual dysfunction, syncope, tachycardia, tinnitus, urinary hesitation, urinary incontinence, urinary retention, urticaria, vasodilatation, vertigo, vision blurred, visual disturbance, weight decreased, and wheezing.

6.2 Postmarketing Experience:

The following adverse reactions have been identified during post approval use of buprenorphine. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Serotonin syndrome: Cases of serotonin syndrome, a potentially life-threatening condition, have been reported during concomitant use of opioids with serotonergic drugs.

Adrenal insufficiency: Cases of adrenal insufficiency have been reported with opioid use, more often following greater than one month of use.

Anaphylaxis: Anaphylaxis has been reported with ingredients contained in buprenorphine transdermal system.

Androgen deficiency: Cases of androgen deficiency have occurred with chronic use of opioids [see Clinical Pharmacology (12.2)].

8.1 Pregnancy

Risk Summary

Prolonged use of opioid analgesics during pregnancy may cause neonatal opioid withdrawal syndrome [see Warnings and Precautions (5.3)]. Available data with buprenorphine transdermal system in pregnant women are insufficient to inform a drug-associated risk for major birth defects and miscarriage.

In animal reproduction studies, buprenorphine caused an increase in the number of stillborn offspring, reduced litter size, and reduced offspring growth in rats at maternal exposure levels that were approximately 10 times that of human subjects who received one buprenorphine transdermal system 20 mcg/hour, the maximum recommended human dose (MRHD) [see Data]. Based on animal data, advise pregnant women of the potential risk to a fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.

Clinical Considerations

Fetal/neonatal adverse reactions

Prolonged use of opioid analgesics during pregnancy for medical or nonmedical purposes can result in physical dependence in the neonate and neonatal opioid withdrawal syndrome shortly after birth. Neonatal opioid withdrawal syndrome presents as irritability, hyperactivity and abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea, and failure to gain weight. The onset, duration, and severity of neonatal opioid withdrawal syndrome vary based on the specific opioid used, duration of use, timing and amount of last maternal use, and rate of elimination of the drug by the newborn. Observe newborns for symptoms of neonatal opioid withdrawal syndrome and manage accordingly [see Warnings and Precautions (5.3)].

Labor and Delivery

Opioids cross the placenta and may produce respiratory depression in neonates. An opioid antagonist such as naloxone must be available for reversal of opioid-induced respiratory depression in the neonate. Buprenorphine transdermal system is not recommended for use in women immediately prior to labor, when shorter acting analgesics or other analgesic techniques are more appropriate. Opioid analgesics, including buprenorphine transdermal system, can prolong labor through actions that temporarily reduce the strength, duration, and frequency of uterine contractions. However, this effect is not consistent and may be offset by an increased rate of cervical dilatation, which tends to shorten labor.

Data

Animal Data

Studies in rats and rabbits demonstrated no evidence of teratogenicity following buprenorphine transdermal system or subcutaneous (SC) administration of buprenorphine during the period of organogenesis. Rats were administered up to one buprenorphine transdermal system 20 mcg/hour every 3 days (Gestation Days 6, 9, 12, & 15) or received daily SC buprenorphine up to 5 mg/kg (Gestation Days 6 to 17). Rabbits were administered four buprenorphine transdermal system 20 mcg/hour every 3 days (Gestation Days 6, 9, 12, 15, 18, and 19) or received daily SC buprenorphine up to 5 mg/kg (Gestation Days 6-19).  No teratogenicity was observed at any dose. AUC values for buprenorphine with buprenorphine transdermal system application and SC injection were approximately 110 and 140 times, respectively, that of human subjects who received the MRHD of one buprenorphine transdermal system 20 mcg/hour.

In a pre- and post-natal study conducted in pregnant and lactating rats, administration of buprenorphine either as buprenorphine transdermal system or SC buprenorphine was associated with toxicity to offspring. Buprenorphine was present in maternal milk. Pregnant rats were administered 1/4 of one buprenorphine transdermal system 5 mcg/hour every 3 days or received daily SC buprenorphine at doses of 0.05, 0.5, or 5 mg/kg from Gestation Day 6 to Lactation Day 21 (weaning). Administration of buprenorphine transdermal system or SC buprenorphine at 0.5 or 5 mg/kg caused maternal toxicity and an increase in the number of stillborns, reduced litter size, and reduced offspring growth at maternal exposure levels that were approximately 10 times that of human subjects who received the MRHD of one buprenorphine transdermal system 20 mcg/hour. Maternal toxicity was also observed at the no observed adverse effect level (NOAEL) for offspring.

8.2 Lactation

Risk Summary

Because of the potential for serious adverse reactions, including excess sedation and respiratory depression in a breastfed infant, advise patients that breastfeeding is not recommended during treatment with buprenorphine transdermal system.

Clinical Considerations

Monitor infants exposed to buprenorphine transdermal system through breast milk for excess sedation and respiratory depression. Withdrawal symptoms can occur in breastfed infants when maternal administration of buprenorphine is stopped or when breast-feeding is stopped.

8.3 Females and Males of Reproductive Potential

Infertility

Chronic use of opioids may cause reduced fertility in females and males of reproductive potential. It is not known whether these effects on fertility are reversible [see Adverse Reactions (6.2), Preclinical Pharmacology (12.2), Nonclinical Toxicology (13.1)].

8.4 Pediatric Use

The safety and efficacy of buprenorphine transdermal system in patients under 18 years of age has not been established.

8.5 Geriatric Use

Of the total number of subjects in the clinical trials (5,415), buprenorphine transdermal system was administered to 1,377 patients aged 65 years and older. Of those, 457 patients were 75 years of age and older. In the clinical program, the incidences of selected buprenorphine transdermal system-related AEs were higher in older subjects. The incidences of application site AEs were slightly higher among subjects < 65 years of age than those ≥ 65 years of age for both buprenorphine transdermal system and placebo treatment groups.

In a single-dose study of healthy elderly and healthy young subjects treated with buprenorphine transdermal system 10 mcg/hour, the pharmacokinetics were similar. In a separate dose-escalation safety study, the pharmacokinetics in the healthy elderly and hypertensive elderly subjects taking thiazide diuretics were similar to those in the healthy young adults. In the elderly groups evaluated, adverse event rates were similar to or lower than rates in healthy young adult subjects, except for constipation and urinary retention, which were more common in the elderly. Although specific dose adjustments on the basis of advanced age are not required for pharmacokinetic reasons, use caution in the elderly population to ensure safe use [see Clinical Pharmacology (12.3)].

Respiratory depression is the chief risk for elderly patients treated with opioids, and has occurred after large initial doses were administered to patients who were not opioid-tolerant or when opioids were co-administered with other agents that depress respiration. Titrate the dosage of buprenorphine transdermal system slowly in geriatric patients and monitor closely for signs of central nervous system and respiratory depression [see Warnings and Precautions (5.5)].

8.6 Hepatic Impairment

In a study utilizing intravenous buprenorphine, peak plasma levels (Cmax) and exposure (AUC) of buprenorphine in patients with mild and moderate hepatic impairment did not increase as compared to those observed in subjects with normal hepatic function. Buprenorphine transdermal system has not been evaluated in patients with severe hepatic impairment. As buprenorphine transdermal system is intended for 7-day dosing, consider the use of alternate analgesic therapy in patients with severe hepatic impairment [see Dosage and Administration (2.4) and Clinical Pharmacology (12.3)].

9.1 Controlled Substance

Buprenorphine transdermal system contains buprenorphine, a Schedule III controlled substance.

9.2 Abuse

Buprenorphine transdermal system contains buprenorphine, a Schedule III controlled substance with an abuse potential similar to other Schedule III opioids. Buprenorphine transdermal system can be abused and is subject to misuse, addiction and criminal diversion [see Warnings and Precautions (5.1)]. The high drug content in extended-release formulations adds to the risk of adverse outcomes from abuse and misuse.

All patients treated with opioids, including buprenorphine transdermal system, require careful monitoring for signs of abuse and addiction, since use of opioid analgesic products carries the risk of addiction even under appropriate medical use.

Prescription drug abuse is the intentional non-therapeutic use of a prescription drug, even once, for its rewarding psychological or physiological effects.

Drug addiction is a cluster of behavioral, cognitive, and physiological phenomena that develop after repeated substance use and includes: a strong desire to take the drug, difficulties in controlling its use, persisting in its use despite harmful consequences, a higher priority given to drug use than to other activities and obligations, increased tolerance, and sometimes a physical withdrawal.

“Drug-seeking” behavior is very common persons with substance use disorders. Drug-seeking tactics include emergency calls or visits near the end of office hours, refusal to undergo appropriate examination, testing, or referral, repeated “loss” of prescriptions, tampering with prescriptions, and reluctance to provide prior medical records or contact information for other treating healthcare providers(s). “Doctor shopping” (visiting multiple prescribers to obtain additional prescriptions) is common among drug abusers and people suffering from untreated addiction. Preoccupation with achieving adequate pain relief can be appropriate behavior in a patient with poor pain control.

Abuse and addiction are separate and distinct from physical dependence and tolerance. Healthcare providers should be aware that addiction may not be accompanied by concurrent tolerance and symptoms of physical dependence in all addicts. In addition, abuse of opioids can occur in the absence of true addiction.

Buprenorphine transdermal system, like other opioids, can be diverted for non-medical use into illicit channels of distribution. Careful record-keeping of prescribing information, including quantity, frequency, and renewal requests, as required by state and federal law, is strongly advised.

Proper assessment of the patient, proper prescribing practices, periodic re-evaluation of therapy, and proper dispensing and storage are appropriate measures that help to limit abuse of opioid drugs.

Risks Specific to the Abuse of Buprenorphine Transdermal System

Buprenorphine transdermal system is intended for transdermal use only. Abuse of buprenorphine transdermal system poses a risk of overdose and death. This risk is increased with concurrent abuse of buprenorphine transdermal system with alcohol and other substances including other opioids and benzodiazepines [see Warnings and Precautions (5.4) and Drug Interactions (7)]. Intentional compromise of the transdermal delivery system will result in the uncontrolled delivery of buprenorphine and pose a significant risk to the abuser that could result in overdose and death [see Warnings and Precautions (5.1)]. Abuse may occur by applying the transdermal system in the absence of legitimate purpose, or by chewing, swallowing, snorting, or injecting buprenorphine extracted from the transdermal system. Parenteral drug abuse is commonly associated with transmission of infectious diseases such as hepatitis and HIV.

9.3 Dependence

Both tolerance and physical dependence can develop during chronic opioid therapy. Tolerance is the need for increasing doses of opioids to maintain a defined effect such as analgesia (in the absence of disease progression or other external factors). Tolerance may occur to both the desired and undesired effects of drugs, and may develop at different rates for different effects.

Physical dependence results in withdrawal symptoms after abrupt discontinuation or a significant dosage reduction of a drug. Withdrawal also may be precipitated through the administration of drugs with opioid antagonist activity (e.g., naloxone, nalmefene), or mixed agonist/antagonist analgesics (e.g., pentazocine, butorphanol, nalbuphine). Physical dependence may not occur to a clinically significant degree until after several days to weeks of continued opioid usage.

Buprenorphine transdermal system should not be abruptly discontinued [see Dosage and Administration (2.4)]. If buprenorphine transdermal system is abruptly discontinued in a physically-dependent patient, a withdrawal syndrome may occur. Some or all of the following can characterize this syndrome: restlessness, lacrimation, rhinorrhea, yawning, perspiration, chills, myalgia, and mydriasis. Other signs and symptoms also may develop, including irritability, anxiety, backache, joint pain, weakness, abdominal cramps, insomnia, nausea, anorexia, vomiting, diarrhea, or increased blood pressure, respiratory rate, or heart rate.

Infants born to mothers physically dependent on opioids will also be physically dependent and may exhibit respiratory difficulties and withdrawal signs [see Use in Specific Populations (8.1)].

12.1 Mechanism of Action

Buprenorphine is a partial agonist at the mu-opioid receptor and an antagonist at the kappa-opioid receptors, an agonist at delta-opioid receptors, and a partial agonist at ORL-1 (nociceptin) receptors. The contributions of these actions to its analgesic profile are unclear.

12.2 Pharmacodynamics

Effects on the Central Nervous System

Buprenorphine produces respiratory depression by direct action on brainstem respiratory centers. The respiratory depression involves a reduction in the responsiveness of the brainstem respiratory centers to both increases in carbon dioxide tension and electrical stimulation.

Buprenorphine causes miosis, even in total darkness. Pinpoint pupils are a sign of opioid overdose but are not pathognomonic (e.g., pontine lesions of hemorrhagic or ischemic origins may produce similar findings). Marked mydriasis rather than miosis may be seen with worsening hypoxia in overdose situations.

Effects on the Gastrointestinal Tract and Other Smooth Muscle

Buprenorphine causes a reduction in motility associated with an increase in smooth muscle tone in the antrum of the stomach and duodenum. Digestion of food in the small intestine is delayed and propulsive contractions are decreased. Propulsive peristaltic waves in the colon are decreased, while tone is increased to the point of spasm, resulting in constipation. Other opioid-induced effects may include a reduction in biliary and pancreatic secretions, spasm of sphincter of Oddi, and transient elevations in serum amylase.

Effects on the Cardiovascular System

Buprenorphine produces peripheral vasodilation, which may result in orthostatic hypotension or syncope. Manifestations of histamine release and/or peripheral vasodilation may include pruritus, flushing, red eyes, sweating, and/or orthostatic hypotension.

Effects on Cardiac Electrophysiology

The effect of buprenorphine transdermal system 10 mcg/hour and 2 x buprenorphine transdermal system 20 mcg/hour on QTc interval was evaluated in a double-blind (buprenorphine transdermal system vs. placebo), randomized, placebo and active-controlled (moxifloxacin 400 mg, open label), parallel-group, dose-escalating, single-dose study in 132 healthy male and female subjects aged 18 to 55 years. The dose escalation sequence for buprenorphine transdermal system during the titration period was: buprenorphine transdermal system 5 mcg/hour for 3 days, then buprenorphine transdermal system 10 mcg/hour for 3 days, then buprenorphine transdermal system 20 mcg/hour for 3 days, then 2 x buprenorphine transdermal system 20 mcg/hour for 4 days. The QTc evaluation was performed during the third day of buprenorphine transdermal system 10 mcg/hour and the fourth day of 2 x buprenorphine transdermal system 20 mcg/hour when the plasma levels of buprenorphine were at steady state for the corresponding doses [see Warnings and Precautions (5.8)].

There was no clinically meaningful effect on mean QTc with a buprenorphine transdermal system dose of 10 mcg/hour. A buprenorphine transdermal system dose of 40 mcg/hour (given as two 20 mcg/hour buprenorphine transdermal systems) prolonged mean QTc by a maximum of 9.2 (90% CI: 5.2-13.3) msec across the 13 assessment time points.

Effects on the Endocrine System

Opioids inhibit the secretion of adrenocorticotropic hormone (ACTH), cortisol, and luteinizing hormone (LH) in humans [see Adverse Reactions (6.2)]. They also stimulate prolactin, growth hormone (GH) secretion, and pancreatic secretion of insulin and glucagon.

Chronic use of opioids may influence the hypothalamic-pituitary-gonadal axis, leading to androgen deficiency that may manifest as low libido, impotence, erectile dysfunction, amenorrhea, or infertility. The causal role of opioids in the clinical syndrome of hypogonadism is unknown because the various medical, physical, lifestyle, and psychological stressors that may influence gonadal hormone levels have not been adequately controlled for in studies conducted to date [see Adverse Reactions (6.2)].

Effects on the Immune System 

Opioids have been shown to have a variety of effects on components of the immune system in in vitro and animal models. The clinical significance of these findings is unknown.  Overall, the effects of opioids appear to be modestly immunosuppressive.

Concentration–Efficacy Relationships

The minimum effective analgesic concentration will vary widely among patients, especially among patients who have been previously treated with potent agonist opioids. The minimum effective analgesic concentration of buprenorphine for any individual patient may increase over time due to an increase in pain, the development of a new pain syndrome, and/or the development of analgesic tolerance [see Dosage and Administration (2.1, 2.3)].

Concentration–Adverse Reaction Relationships

There is a relationship between increasing buprenorphine plasma concentration and increasing frequency of dose-related opioid adverse reactions such as nausea, vomiting, CNS effects, and respiratory depression. In opioid-tolerant patients, the situation may be altered by the development of tolerance to opioid-related adverse reactions [see Dosage and Administration (2.1, 2.2, 2.3)].

12.3 Pharmacokinetics

Absorption

Each buprenorphine transdermal system provides delivery of buprenorphine for 7 days. Steady state was achieved during the first application by Day 3 (see Figure 2).

Figure 2: Mean (SD) Buprenorphine Plasma Concentrations Following Three Consecutive Applications of Buprenorphine Transdermal System 10 mcg/hour (N = 36 Healthy Subjects)

Figure 2: Mean (SD) Buprenorphine Plasma Concentrations Following Three Consecutive Applications of Buprenorphine Transdermal System 10 mcg/hour (N = 36 Healthy Subjects)

Buprenorphine transdermal system 5, 10, and 20 mcg/hour provide dose-proportional total buprenorphine exposures (AUC) following 7-day applications. Buprenorphine transdermal system single 7-day application and steady-state pharmacokinetic parameters are summarized in Table 7. Plasma buprenorphine concentrations after titration showed no further change over the 60-day period studied. 

Transdermal delivery studies showed that intact human skin is permeable to buprenorphine. In clinical pharmacology studies, the median time for buprenorphine transdermal system 10 mcg/hour to deliver quantifiable buprenorphine concentrations (≥ 25 pg/mL) was approximately 17 hours.

The absolute bioavailability of buprenorphine transdermal system relative to IV administration, following a 7-day application, is approximately 15% for all doses (buprenorphine transdermal system 5, 10, and 20 mcg/hour).

Effects of Application Site

A study in healthy subjects demonstrated that the pharmacokinetic profile of buprenorphine delivered by buprenorphine transdermal system 10 mcg/hour is similar when applied to the upper outer arm, upper chest, upper back, or the side of the chest [see Dosage and Administration (2.6)].

The reapplication of buprenorphine transdermal system 10 mcg/hour after various rest periods to the same application site in healthy subjects showed that the minimum rest period needed to avoid variability in drug absorption is 3 weeks (21 days) [see Dosage and Administration (2.5)].

Effects of Heat

In a study of healthy subjects, application of a heating pad directly on the buprenorphine transdermal system 10 mcg/hour caused a 26% - 55% increase in blood concentrations of buprenorphine. Concentrations returned to normal within 5 hours after the heat was removed. For this reason, instruct patients not to apply heating pads directly to the buprenorphine transdermal system during system wear [see Warnings and Precautions (5.13)].

Fever may increase the permeability of the skin, leading to increased buprenorphine concentrations during buprenorphine transdermal system treatment. As a result, febrile patients are at increased risk for the possibility of buprenorphine transdermal system-related reactions during treatment with buprenorphine transdermal system. Monitor patients with febrile illness for adverse effects and consider dose adjustment [see Warnings and Precautions (5.14)]. In a crossover study of healthy subjects receiving endotoxin or placebo challenge during buprenorphine transdermal system 10 mcg/hour wear, the AUC and Cmax were similar despite a physiologic response of mild fever to endotoxin.

Distribution

Buprenorphine is approximately 96% bound to plasma proteins, mainly to alpha- and beta-globulin.

Studies of IV buprenorphine have shown a large volume of distribution (approximately 430 L), implying extensive distribution of buprenorphine.

CSF buprenorphine concentrations appear to be approximately 15-25% of concurrent plasma concentrations.

Elimination

Metabolism

Buprenorphine metabolism in the skin following buprenorphine transdermal system application is negligible.

Buprenorphine primarily undergoes N-dealkylation by CYP3A4 to norbuprenorphine and glucuronidation by UGT-isoenzymes (mainly UGT1A1 and 2B7) to buprenorphine 3β-O-glucuronide. Norbuprenorphine, the major metabolite, is also glucuronidated (mainly UGT1A3) prior to excretion.

Norbuprenorphine is the only known active metabolite of buprenorphine. It has been shown to be a respiratory depressant in rats, but only at concentrations at least 50-fold greater than those observed following application to humans of buprenorphine transdermal system 20 mcg/hour.

Excretion

Following IV administration, buprenorphine and its metabolites are secreted into bile and excreted in urine.

Following intramuscular administration of 2 mcg/kg dose of buprenorphine, approximately 70% of the dose was excreted in feces within 7 days. Approximately 27% was excreted in urine.

Following transdermal application, buprenorphine is eliminated via hepatic metabolism, with subsequent biliary excretion and renal excretion of soluble metabolites. After removal of buprenorphine transdermal system, mean buprenorphine concentrations decrease approximately 50% within 10-24 hours, followed by decline with an apparent terminal half-life of approximately 26 hours.

Since metabolism and excretion of buprenorphine occur mainly via hepatic elimination, reductions in hepatic blood flow induced by some general anesthetics (e.g., halothane) and other drugs may result in a decreased rate of hepatic elimination of the drug, leading to increased plasma concentrations.

The total clearance of buprenorphine is approximately 55 L/hour in postoperative patients.

Drug Interaction Studies

Effect of CYP3A4 inhibitors

In a drug-drug interaction study, buprenorphine transdermal system 10 mcg/hour (single dose x 7 days) was co-administered with 200 mg ketoconazole, a strong CYP3A4 inhibitor or ketoconazole placebo twice daily for 11 days and the pharmacokinetics of buprenorphine and its metabolites were evaluated. Plasma buprenorphine concentrations did not accumulate during co-medication with ketoconazole 200 mg twice daily. Based on the results from this study, metabolism during therapy with buprenorphine transdermal system is not expected to be affected by co-administration of CYP3A4 inhibitors [see Drug Interactions (7)].

Antiretroviral agents have been evaluated for CYP3A4 mediated interactions with sublingual buprenorphine. Nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs) do not appear to have clinically significant interactions with buprenorphine. However, certain protease inhibitors (PIs) with CYP3A4 inhibitory activity such as atazanavir and atazanavir/ritonavir resulted in elevated levels of buprenorphine and norbuprenorphine when buprenorphine and naloxone were administered sublingually. Cmax and AUC for buprenorphine increased by up to 1.6 and 1.9 fold, and Cmax and AUC for norbuprenorphine increased by up to 1.6 and 2.0 fold respectively, when sublingual buprenorphine was administered with these PIs. Patients in this study reported increased sedation, and symptoms of opiate excess have been found in post-marketing reports of patients receiving buprenorphine and atazanavir with and without ritonavir concomitantly. It should be noted that atazanavir is both a CYP3A4 and UGT1A1 inhibitor. As such, the drug-drug interaction potential for buprenorphine with CYP3A4 inhibitors is likely to be dependent on the route of administration as well as the specificity of enzyme inhibition [see Drug Interactions (7)].

Effect of CYP3A4 Inducers

The interaction between buprenorphine and CYP3A4 inducers has not been studied.

Specific Populations

Age: Geriatric Patients

Following a single application of buprenorphine transdermal system 10 mcg/hour to 12 healthy young adults (mean age 32 years) and 12 healthy elderly subjects (mean age 72 years), the pharmacokinetic profile of buprenorphine transdermal system was similar in healthy elderly and healthy young adult subjects, though the elderly subjects showed a trend toward higher plasma concentrations immediately after buprenorphine transdermal system removal. Both groups eliminated buprenorphine at similar rates after system removal [see Use in Specific Populations (8.5)].

In a study of healthy young subjects, healthy elderly subjects, and elderly subjects treated with thiazide diuretics, buprenorphine transdermal system at a fixed dose-escalation schedule (buprenorphine transdermal system 5 mcg/hour for 3 days, followed by buprenorphine transdermal system 10 mcg/hour for 3 days and buprenorphine transdermal system 20 mcg/hour for 7 days) produced similar mean plasma concentration vs. time profiles for each of the three subject groups. There were no significant differences between groups in buprenorphine Cmax or AUC [see Use in Specific Populations (8.5)].

Sex

In a pooled data analysis utilizing data from several studies that administered buprenorphine transdermal system 10 mcg/hour to healthy subjects, no differences in buprenorphine Cmax and AUC or body-weight normalized Cmax and AUC were observed between males and females treated with buprenorphine transdermal system.

Hepatic Impairment

The pharmacokinetics of buprenorphine following an IV infusion of 0.3 mg of buprenorphine were compared in 8 patients with mild impairment (Child-Pugh A), 4 patients with moderate impairment (Child-Pugh B) and 12 subjects with normal hepatic function. Buprenorphine and norbuprenorphine exposure did not increase in the mild and moderate hepatic impairment patients.

Buprenorphine transdermal system has not been evaluated in patients with severe (Child-Pugh C) hepatic impairment [see Warnings and Precautions (5.10), and Use in Specific Populations (8.6)].

Renal Impairment

No studies in patients with renal impairment have been performed with buprenorphine transdermal system.

In an independent study, the effect of impaired renal function on buprenorphine pharmacokinetics after IV bolus and after continuous IV infusion administrations was evaluated. It was found that plasma buprenorphine concentrations were similar in patients with normal renal function and in patients with impaired renal function or renal failure. In a separate investigation of the effect of intermittent hemodialysis on buprenorphine plasma concentrations in chronic pain patients with end-stage renal disease who were treated with a transdermal buprenorphine product (marketed outside the US) up to 70 mcg/hour, no significant differences in buprenorphine plasma concentrations before or after hemodialysis were observed.

No notable relationship was observed between estimated creatinine clearance rates and steady-state buprenorphine concentrations among patients during buprenorphine transdermal system therapy.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Carcinogenesis

Buprenorphine administered daily by skin painting to Sprague Dawley rats for 100 weeks at dosages (20, 60, or 200 mg/kg) produced systemic exposures (based on AUC) that ranged from approximately 130 to 350 times that of human subjects administered the maximum recommended human dose (MRHD) of buprenorphine transdermal system 20 mcg/hour.An increased incidence of benign testicular interstitial cell tumors, considered buprenorphine treatment-related, was observed in male rats compared with concurrent controls. The tumor incidence was also above the highest incidence in the historical control database of the testing facility. These tumors were noted at 60 mg/kg/day and higher at approximately 220 times the proposed MRHD based on AUC. The no observed effect level (NOEL) was 20 mg/kg/day (approximately 140 times the proposed MRHD based on AUC). The mechanism leading to the tumor findings and the relevance to humans is unknown.

Buprenorphine was administered by skin painting to hemizygous Tg.AC mice over a 6-month study period. At the dosages administered daily (18.75, 37.5, 150, or 600 mg/kg/day), buprenorphine was not carcinogenic or tumorigenic at systemic exposure to buprenorphine, based on AUC, of up to approximately 1000 times that of human subjects administered buprenorphine transdermal system 20 mcg/hour, the MRHD.

Mutagenesis

Buprenorphine was not genotoxic in three in vitro genetic toxicology studies (bacterial mutagenicity test, mouse lymphoma assay, chromosomal aberration assay in human peripheral blood lymphocytes), and in one in vivo mouse micronucleus test.

Impairment of Fertility

Buprenorphine transdermal system (1/4 of a buprenorphine transdermal system 5 mcg/hour, one buprenorphine transdermal system 5 mcg/hour, or one buprenorphine transdermal system 20 mcg/hour every 3 days in males for 4 weeks prior to mating for a total of 10 weeks and in females for 2 weeks prior to mating through Gestation Day 7) had no effect on fertility or general reproductive performance of rats at AUC-based exposure levels as high as approximately 65 times (females) and 100 times (males) that for human subjects who received buprenorphine transdermal system 20 mcg/hour, the MRHD.