Central Nervous System

The precise mechanism of the analgesic action is unknown. However, specific CNS (central nervous system) opioid receptors for endogenous compounds with opioid-like activity have been identified throughout the brain and spinal cord and play a role in the analgesic effects of this drug. In addition, opioid receptors have also been identified within the PNS (peripheral nervous system). The role that these receptors play in these drugs’ analgesic effects is unknown.

Opioids produce respiratory depression likely by direct action on brain stem respiratory centers. The respiratory depression involves a reduction in the responsiveness of the brain stem respiratory centers to both increases in carbon dioxide tension and electrical stimulation.

Opioids depress the cough reflex by direct effect on the cough center in the medulla oblongata. Antitussive effects may occur with doses lower than those usually required for analgesia. Opioids cause 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 origin may produce similar findings). Marked mydriasis rather than miosis may be seen with hypoxia in overdose situations (see OVERDOSAGE: Signs and Symptoms).

Gastrointestinal Tract and Other Smooth Muscle

Opioids cause 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 may be increased to the point of spasm resulting in constipation. Other opioid-induced effects may include a reduction in gastric, biliary and pancreatic secretions, spasm of sphincter of Oddi, and transient elevations in serum amylase.

Cardiovascular System

Opioids produce peripheral vasodilation which may result in orthostatic hypotension. Release of histamine can occur and may contribute to opioid-induced hypotension. Manifestations of histamine release may include orthostatic hypotension, pruritus, flushing, red eyes, and sweating. Animal studies have shown that oxymorphone has a lower propensity to cause histamine release than other opioids.

Endocrine System

Opioids have been shown to have a variety of effects on the secretion of hormones. Opioids inhibit the secretion of ACTH, cortisol, and luteinizing hormone (LH) in humans. They also stimulate prolactin, growth hormone (GH) secretion, and pancreatic secretion of insulin and glucagon in humans and other species, rats and dogs. Thyroid stimulating hormone (TSH) has been shown to be both inhibited and stimulated by opioids.

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.

Pharmacodynamics

Pharmacokinetics

Drug-Drug Interactions

In vitro studies revealed little to no biotransformation of oxymorphone to 6-OH-oxymorphone by any of the major cytochrome P450 (CYP P450) isoforms at therapeutically relevant oxymorphone plasma concentrations.

No inhibition of any of the major CYP P450 isoforms was observed when oxymorphone was incubated with human liver microsomes at concentrations of ≤ 50 μM. An inhibition of CYP3A4 activity occurred at oxymorphone concentrations ≥150 µM. Therefore, it is not expected that oxymorphone, or its metabolites will act as inhibitors of any of the major CYP P450 enzymes in vivo.

Increases in the activity of the CYP 2C9 and CYP 3A4 isoforms occurred when oxymorphone was incubated with human hepatocytes. However, clinical drug interaction studies with OPANA ER showed no induction of CYP450 3A4 or 2C9 enzyme activity, indicating that no dose adjustment for CYP 3A4- or 2C9-mediated drug-drug interactions is required.

12-Week Study in Opioid-Naïve Patients with Low Back Pain

Patients with chronic low back pain who were suboptimally responsive to their current non-opioid therapy entered a 4-week, open-label dose titration phase. Patients initiated therapy with two days of treatment with OPANA ER 5 mg, every 12 hours. Thereafter, patients were titrated to a stabilized dose, at increments of 5-10 mg every 12 hours every 3-7 days. Of the patients who were able to stabilize within the Open-Label Titration Period, the mean±SD VAS score at Screening was 69.4±11.8 mm and at Baseline (beginning of Double-Blind Period) were 18.5±11.2 mm and 19.3±11.3 mm for the oxymorphone ER and placebo groups, respectively. Sixty three percent of the patients enrolled were able to titrate to a tolerable dose and were randomized into a 12-week double-blind treatment phase with placebo or their stabilized dose of OPANA ER. The mean±SD stabilized doses were 39.2±26.4 mg and 40.9±25.3 mg for the OPANA ER and placebo groups, respectively; total daily doses ranged from 10-140 mg. During the first 4 days of double-blind treatment patients were allowed an unlimited number of OPANA, an immediate-release (IR) formulation of oxymorphone, 5 mg tablets, every 4-6 hours as supplemental analgesia; thereafter the number of OPANA was limited to two tablets per day. This served as a tapering method to minimize opioid withdrawal symptoms in placebo patients. Sixty-eight percent of patients treated with OPANA ER completed the 12-week treatment compared to forty seven percent of patients treated with placebo. OPANA ER provided superior analgesia compared to placebo. The analgesic effect of OPANA ER was maintained throughout the double-blind treatment period in 89% of patients who completed the study. These patients reported a decrease, no change, or a ≤10 mm increase in VAS score from Day 7 until the end of the study.

A significantly higher proportion of OPANA ER patients (81.4%) had at least a 30% reduction in pain score from screening to study endpoint compared to placebo patients (51.7%). The proportion of patients with various degrees of improvement from screening to study endpoint is shown in Figure 1.

Figure 1: Percent Reduction in Average Pain Intensity from Screening to Final Visit

12-Week Study in Opioid-Experienced Patients with Low Back Pain

Patients currently on chronic opioid therapy entered a 4-week, open-label titration phase with OPANA ER dosed every 12 hours at an approximated equianalgesic dose of their pre-study opioid medication. Of the patients who were able to stabilize within the Open‑Label Titration Period, the mean±SD VAS score at Screening was 69.5±17.0 mm and at Baseline (beginning of Double-Blind Period) were 23.9±12.1 mm and 22.2±10.8 mm for the oxymorphone ER and placebo groups, respectively. Stabilized patients entered a 12‑week double-blind treatment phase with placebo or their stabilized dose of OPANA ER. The mean±SD stabilized doses were 80.9±59.3 mg and 93.3±61.3 mg for the OPANA ER and placebo groups, respectively; total daily doses ranged from 20-260 mg. During the first 4 days of double-blind treatment, patients were allowed an unlimited number of OPANA 5 mg tablets, every 4-6 hours as supplemental analgesia; thereafter the number of OPANA was limited to two tablets per day. This served as a tapering method to minimize opioid withdrawal symptoms in placebo patients. Fifty seven percent of patients were titrated to a stabilized dose within approximately 4 weeks of OPANA ER dose titration. Seventy percent of patients treated with OPANA ER and 26% of patients treated with placebo completed the 12-week treatment. OPANA ER provided superior analgesia compared to placebo . The analgesic effect of OPANA ER was maintained throughout the double-blind treatment period in 80 % of patients who completed the study. These patients reported a decrease, no change, or a ≤10 mm increase in VAS score from Day 7 until the end of the study.

A significantly higher proportion of OPANA ER patients (79.7%) had at least a 30% reduction in pain score from screening to study endpoint compared to placebo patients (34.8%). Proportion of patients with various degrees of improvement from screening to study endpoint is shown in Figure 2.

Figure 2: Percent Reduction in Average Pain Intensity from Screening to Final Visit

Misuse, Abuse and Diversion of Opioids

OPANA ER contains oxymorphone, an opioid agonist similar to morphine, and is a Schedule II controlled substance. Opioid agonists have the potential for being abused and are sought by drug abusers and people with addiction disorders and are subject to criminal diversion.

Oxymorphone can be abused in a manner similar to other opioid agonists, legal or illicit. This should be considered when prescribing or dispensing OPANA ER in situations where the physician or pharmacist is concerned about an increased risk of misuse, abuse, or diversion.

OPANA ER tablets may be abused by crushing, chewing, snorting or injecting the product. These practices will result in the uncontrolled delivery of the opioid and pose a significant risk to the abuser that could result in overdose and death (seeWARNINGS and WARNINGS: Drug Abuse and Addiction).

Concerns about abuse, addiction, and diversion should not prevent the proper management of pain.

Healthcare professionals should contact their State Professional Licensing Board, or State Controlled Substances Authority for information on how to prevent and detect abuse or diversion of this product.

Interactions with Alcohol and Drugs of Abuse

Oxymorphone may be expected to have additive effects when used in conjunction with alcohol, other opioids, or illicit drugs that cause central nervous system depression because respiratory depression, hypotension, and profound sedation or coma may result. An in vivo study examined the effect of alcohol (40%, 20%, 4% and 0%) on the bioavailability of a single dose of 40 mg of OPANA ER in healthy, fasted volunteers. The results showed that the oxymorphone mean AUC was 13% higher (not statistically significant) after co-administration of 240 mL of 40% alcohol. The AUC was essentially unaffected in subjects following the co-administration of OPANA ER and ethanol (240 mL of 20% or 4% ethanol).

There was a highly variable effect on Cmax with concomitant administration of alcohol and OPANA ER. The change in Cmax ranged from a decrease of 50% to an increase of 270% across all conditions studied. Following concomitant administration of 240 mL of 40% ethanol the Cmax increased on average by 70%, and up to 270% in individual subjects. Following the concomitant administration of 240mL of 20% ethanol the Cmax increased on average by 31% and up to 260% in individual subjects. Following the concomitant administration of 240 mL of 4 % ethanol, the Cmax increased by 7% on average and as much as 110% for individual subjects.

Drug Abuse and Addiction

Respiratory Depression

Respiratory depression is the chief hazard of OPANA ER. Respiratory depression is a particular potential problem in elderly or debilitated patients as well as in those suffering from conditions accompanied by hypoxia or hypercapnia when even moderate therapeutic doses may dangerously decrease pulmonary ventilation.

OPANA ER should be administered with extreme caution to patients with conditions accompanied by hypoxia, hypercapnia, or decreased respiratory reserve such as: asthma, chronic obstructive pulmonary disease or cor pulmonale, severe obesity, sleep apnea syndrome, myxedema, kyphoscoliosis, CNS depression or coma. In these patients, even usual therapeutic doses of oxymorphone may decrease respiratory drive while simultaneously increasing airway resistance to the point of apnea. Alternative non-opioid analgesics should be considered, and oxymorphone should be employed only under careful medical supervision at the lowest effective dose in such patients.

Interactions with Other Central Nervous System Depressants

Patients receiving other opioid analgesics, general anesthetics, phenothiazines or other tranquilizers, sedatives, hypnotics, or other CNS depressants (including alcohol) concomitantly with oxymorphone may experience respiratory depression, hypotension, profound sedation, or coma (see PRECAUTIONS: Drug-Drug Interactions).

Head Injury and Increased Intracranial Pressure

In the presence of head injury, intracranial lesions or a preexisting increase in intracranial pressure, the possible respiratory depressant effects of opioid analgesics and their potential to elevate cerebrospinal fluid pressure (resulting from vasodilation following CO2 retention) may be markedly exaggerated. Furthermore, opioid analgesics can produce effects on pupillary response and consciousness, which may obscure neurologic signs of further increases in intracranial pressure in patients with head injuries.

Hypotensive Effect

OPANA ER, like all opioid analgesics, may cause severe hypotension in an individual whose ability to maintain blood pressure has been compromised by a depleted blood volume, or after concurrent administration with drugs such as phenothiazines or other agents which compromise vasomotor tone. OPANA ER, like all opioid analgesics, should be administered with caution to patients in circulatory shock, since vasodilation produced by the drug may further reduce cardiac output and blood pressure.

Hepatic Impairment

A study of OPANA ER in patients with hepatic disease indicated greater plasma concentrations than those with normal hepatic function (see CLINICAL PHARMACOLOGY). OPANA ER should be used with caution in patients with mild impairment. These patients should be started with the lowest dose and titrated slowly while carefully monitoring for side effects. OPANA ER is contraindicated for patients with moderate and severe hepatic impairment (see CONTRAINDICATIONS, WARNINGS, and DOSAGE AND ADMINISTRATION).

General

Opioid analgesics should be used with caution especially when combined with other drugs, and should be reserved for cases where the benefits of opioid analgesia outweigh the known potential risks of respiratory depression, altered mental state and postural hypotension. OPANA ER should be used with caution in elderly and debilitated patients and in patients who are known to be sensitive to central nervous system depressants, such as those with cardiovascular, pulmonary, renal, or hepatic disease.

OPANA ER should be used with caution in the following conditions: acute alcoholism; adrenocortical insufficiency (e.g., Addison's disease); CNS depression or coma; delirium tremens; kyphoscoliosis associated with respiratory depression; myxedema or hypothyroidism; prostatic hypertrophy or urethral stricture; severe impairment of pulmonary or renal function; moderate impairment of hepatic function; and toxic psychosis.

The administration of oxymorphone may obscure the diagnosis or clinical course in patients with acute abdominal conditions. Oxymorphone may aggravate convulsions in patients with convulsive disorders, and all opioids may induce or aggravate seizures in some clinical settings.

OPANA ER is intended for use in patients who require more than several days continuous treatment with an opioid analgesic.

Ambulatory Surgery and Post-Operative Use

OPANA ER is not indicated for pre-emptive analgesia (administration pre-operatively for the management of post-operative pain).

OPANA ER is not indicated for pain in the immediate post-operative period (12-24 hours following surgery) for patients not previously taking opioids because of the risk of oversedation and respiratory depression requiring reversal with opioid antagonists.

OPANA ER is not indicated for pain in the post-operative period if the pain is mild or not expected to persist for an extended period of time.

OPANA ER is only indicated for postoperative use in the patient if the patient is already receiving the drug prior to surgery or if the postoperative pain is expected to be moderate to severe and persist for an extended period of time. Physicians should individualize treatment, moving from parenteral to oral analgesics as appropriate (see American Pain Society guidelines).

Patients who are already receiving OPANA ER as part of ongoing analgesic therapy may be safely continued on the drug if appropriate dosage adjustments are made considering the procedure, other drugs given, and the temporary changes in physiology caused by the surgical intervention (see DOSAGE AND ADMINISTRATION).

OPANA ER, like other opioids, decreases bowel motility. Ileus is a common post-operative complication, especially after intra-abdominal surgery with opioid analgesia. Caution should be taken to monitor for decreased bowel motility in post-operative patients receiving opioids. Standard supportive therapy should be implemented.

Use in Pancreatic/Biliary Tract Disease

OPANA ER, like other opioids, may cause spasm of the sphincter of Oddi and should be used with caution in patients with biliary tract disease, including acute pancreatitis.

Physical Dependence and Tolerance

Physical dependence is the occurrence of withdrawal symptoms after abrupt discontinuation of a drug or upon administration of an opioid antagonist or mixed opioid agonist/antagonist agent. 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). The development of physical dependence and tolerance is not unusual during chronic opioid therapy.

If OPANA ER is abruptly discontinued in a physically-dependent patient, an abstinence syndrome may occur. Some or all of the following can characterize this syndrome: restlessness, lacrimation, rhinorrhea, yawning, perspiration, chills, myalgia, and mydriasis. Other 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.

In general, OPANA ER should not be abruptly discontinued. However, OPANA ER, like other opioids, can be safely discontinued without the development of withdrawal symptoms by slowly tapering the daily dose (see DOSAGE AND ADMINISTRATION: Cessation of Therapy).

Information for Patients/Caregivers

1. Patients should be advised that OPANA ER contains oxymorphone, a morphine-like pain reliever, and should be taken only as directed.
   
   
2. Patients should be advised that OPANA ER is designed to work properly only if swallowed whole. The extended-release tablets may release all their contents at once if broken, chewed or crushed, resulting in a risk of fatal overdose of oxymorphone.
   
   
3. Patients must not consume alcoholic beverages, or prescription or non-prescription medications containing alcohol, while on OPANA ER therapy. The co-ingestion of alcohol with OPANA ER may result in increased plasma levels and a potentially fatal overdose of oxymorphone.
   
   
4. Appropriate pain management requires changes in the dose to maintain best pain control. Patients should be advised of the need to contact their physician if pain control is inadequate, but not to change the dose of OPANA ER without consulting their physician.
   
   
5. Patients should be advised to report episodes of breakthrough pain and adverse experiences occurring during therapy to their doctor. Individualization of dosage is essential to make optimal use of this medication.
   
   
6. Patients should be cautioned that OPANA ER may cause drowsiness, dizziness, or lightheadedness, and may impair mental and/or physical abilities required for the performance of potentially hazardous tasks, such as driving a car, operating machinery, etc.
   
   
7. Patients should not combine OPANA ER with alcohol or other central nervous system depressants (sleep aids, tranquilizers) except by the orders of the prescribing physician, because additive effects may occur, resulting in serious injury or death.
   
   
8. Patients taking OPANA ER should be advised of the potential for severe constipation. Appropriate laxatives and/or stool softeners and other therapeutic approaches may be considered for use with the initiation of OPANA ER therapy.
   
   
9. Patients should be advised not to adjust the dose of OPANA ER without consulting the prescribing professional.
   
   
10. Patients should be advised that OPANA ER is a potential drug of abuse. They should protect it from theft, and it should never be given to anyone other than the individual for whom it was prescribed.
    
    
11. Women of childbearing potential who become, or are planning to become pregnant should be advised to consult their physician regarding the effects of opioid analgesics and other drug use during pregnancy on themselves and their unborn child.
    
    
12. If patients have been receiving treatment with OPANA ER for more than a few days to weeks and cessation of therapy is indicated, they should be counseled on the importance of safely tapering the dose and that abruptly discontinuing the medication could precipitate withdrawal symptoms. The physician should determine a dose schedule to accomplish a gradual discontinuation of the medication.
    
    
13. As with any potent opioid, misuse of OPANA ER may result in serious adverse events. Patients should be instructed to keep OPANA ER in a secure place out of the reach of children and pets. Accidental consumption especially in children can result in overdose or death. When OPANA ER is no longer needed, the unused tablets should be destroyed by flushing down the toilet.

Use in Drug and Alcohol Addiction

OPANA ER is not approved for use in detoxification or maintenance treatment of opioid addiction. However, the history of an addictive disorder does not necessarily preclude the use of this medication for the treatment of chronic pain. These patients will require intensive monitoring for signs of misuse, abuse, or addiction.

Drug-Drug Interactions

Oxymorphone is highly metabolized principally in the liver and undergoes reduction or conjugation with glucuronic acid to form both active and inactive metabolites (see Pharmacokinetics: Metabolism).

Use with CNS Depressants

The concomitant use of other CNS depressants including sedatives, hypnotics, tranquilizers, general anesthetics, phenothiazines, other opioids, and alcohol may produce additive CNS depressant effects. OPANA ER, like all opioid analgesics, should be started at 1/3 to 1/2 of the usual dose in patients who are concurrently receiving other central nervous system depressants including sedatives or hypnotics, general anesthetics, phenothiazines, tranquilizers, and alcohol because respiratory depression, hypotension, and profound sedation or coma may result, and titrated slowly as necessary for adequate pain relief.

Additive effects resulting in respiratory depression, hypotension, profound sedation or coma may result if these drugs are taken in combination with the usual doses of OPANA ER. No specific interaction between oxymorphone and monoamine oxidase inhibitors has been observed, but caution in the use of any opioid in patients taking this class of drugs is appropriate.

When combined therapy with any of the above medications is contemplated, the dose of one or both agents should be reduced (see WARNINGS and DOSAGE AND ADMINISTRATION).

Interactions with Mixed Agonist/Antagonist Opioid Analgesics

Agonist/antagonist analgesics (i.e., pentazocine, nalbuphine, butorphanol, or buprenorphine) should not be administered to patients who have received or are receiving a course of therapy with a pure opioid agonist analgesic, such as OPANA ER. In this situation, mixed agonist/antagonist analgesics may reduce the analgesic effect of OPANA ER and/or may precipitate withdrawal symptoms.

Other

Anticholinergics or other medications with anticholinergic activity when used concurrently with opioid analgesics may result in increased risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.

In addition, CNS side effects have been reported (confusion, disorientation, respiratory depression, apnea, seizures) following coadministration of cimetidine with opioid analgesics; no clear-cut cause and effect relationship was established.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Pregnancy

The safety of using oxymorphone in pregnancy has not been established with regard to possible adverse effects on fetal development. The use of OPANA ER in pregnancy, in nursing mothers, or in women of child-bearing potential requires that the possible benefits of the drug be weighed against the possible hazards to the mother and the child (see PRECAUTIONS).

Labor and Delivery

Opioids cross the placenta and may produce respiratory depression and psycho-physiologic effects in neonates. OPANA ER is not recommended for use in women during and immediately prior to labor, when use of shorter acting analgesics or other analgesic techniques are more appropriate. Occasionally, opioid analgesics may prolong labor through actions which 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. Neonates whose mothers received opioid analgesics during labor should be observed closely for signs of respiratory depression. A specific opioid antagonist, such as naloxone or nalmefene, should be available for reversal of opioid-induced respiratory depression in the neonate.

Nursing Mothers

It is not known whether oxymorphone is excreted in human milk. Because many drugs, including some opioids, are excreted in human milk, caution should be exercised when OPANA ER is administered to a nursing woman. Ordinarily, nursing should not be undertaken while a patient is receiving oxymorphone because of the possibility of sedation and/or respiratory depression in the infant.

Pediatric Use

Safety and effectiveness of OPANA ER in pediatric patients below the age of 18 years have not been established.

Geriatric Use

OPANA ER should be used with caution in elderly patients. The plasma levels of oxymorphone are about 40% higher in elderly (≥65 years of age) than in younger subjects (see CLINICAL PHARMACOLOGY). Elderly patients should initially receive smaller starting doses of oxymorphone and dose titration should proceed cautiously.

Of the total number of subjects in clinical studies of OPANA ER, 27 percent were 65 and over, while 9 percent were 75 and over. No overall differences in effectiveness were observed between these subjects and younger subjects. There were several adverse events that were more frequently observed in subjects 65 and over compared to younger subjects. These adverse events included dizziness, somnolence, confusion, and nausea.

Hepatic Impairment

A study of OPANA ER in patients with hepatic disease indicated greater plasma concentrations than those with normal hepatic function (see CLINICAL PHARMACOLOGY). OPANA ER should be used with caution in patients with mild impairment. These patients should be started with the lowest dose and titrated slowly while carefully monitoring for side effects. OPANA ER is contraindicated for patients with moderate and severe hepatic impairment (see CONTRAINDICATIONS, WARNINGS, and DOSAGE AND ADMINISTRATION).

Renal Impairment

In a study of OPANA ER, patients with moderate to severe renal impairment were shown to have an increase in bioavailability ranging from 57-65% (see CLINICAL PHARMACOLOGY). These patients should be started cautiously with lower doses of OPANA ER and titrated slowly while carefully monitored for side effects (see DOSAGE AND ADMINISTRATION).

Gender Differences

When normalized for body weight, gender differences were not observed (see CLINICAL PHARMACOLOGY). In clinical studies, the overall incidence rates for one or more adverse events were slightly higher among females than males for both OPANA ER subjects and placebo subjects.

Adverse Reactions Reported in Placebo-Controlled Trials

The following table lists adverse reactions that were reported in at least 2% of patients in placebo-controlled trials (N=5)

Table 4: Adverse Reactions Reported in Placebo-Controlled Clinical Trials with Incidence ≥2% in Patients Receiving OPANA ER.

MedDRA Preferred Term	OPANA ER (N=1259)	Placebo (N=461)
Nausea	33.1%	13.2%
Constipation	27.6%	13.2%
Dizziness (Exc Vertigo)	17.8%	7.6%
Somnolence	17.2%	2.2%
Vomiting	15.6%	4.1%
Pruritus	15.2%	7.6%
Headache	12.2%	5.6%
Sweating increased	8.6%	8.7%
Dry mouth	6.4%	0.7%
Sedation	5.9%	7.6%
Diarrhea	4.3%	5.6%
Insomnia	4.0%	2.0%
Fatigue	3.9%	1.3%
Appetite decreased	2.9%	0.4%
Abdominal pain	2.5%	1.5%

Adverse Reactions Reported in All Clinical Trials

A total of 2011 patients were treated with OPANA ER in the Phase 2/3 controlled and open-label clinical trials. The clinical trials consisted of patients with moderate to severe chronic pain and post surgical pain.

The adverse reactions are presented in the following manner: most common, common, and less common adverse reactions.

The most common adverse drug reactions (≥10%) reported at least once by patients treated with OPANA ER in the clinical trials were nausea, constipation, dizziness (exc. vertigo), vomiting, pruritus, somnolence, headache, sweating increased, and sedation.

The common (≥1% - <10%) adverse drug reactions reported at least once by patients treated with OPANA ER in the clinical trials organized by MedDRA’s (Medical Dictionary for Regulatory Activities) System Organ Class were:

Eye disorders: vision blurred

Gastrointestinal disorders: diarrhea, abdominal pain, dyspepsia

General disorders and administration site conditions: dry mouth, appetite decreased, fatigue, lethargy, weakness, pyrexia, dehydration, weight decreased, edema

Nervous system disorders: insomnia

Psychiatricdisorders: anxiety, confusion, disorientation, restlessness, nervousness, depression

Respiratory, thoracic and mediastinal disorders: dyspnea

Vascular disorders: flushing and hypertension

Other less common adverse reactions known with opioid treatment that were seen <1% in the OPANA ER trials include the following in alphabetical order.

Abdominal distention, agitation, allergic reactions, bradycardia, central nervous system depression, clamminess, depressed level of consciousness, dermatitis, difficult micturition, dysphoria, euphoric mood, feeling jittery, hallucination, hot flashes, hypersensitivity, hypotension, hypoxia, ileus, mental impairment, mental status changes, miosis, oxygen saturation decreased, palpitation, postural hypotension, respiratory depression, respiratory distress, respiratory rate decreased, syncope, tachycardia, urinary retention, urticaria, and visual disturbances.

Signs and Symptoms

Acute overdosage with OPANA ER is characterized by respiratory depression (a decrease in respiratory rate and/or tidal volume, Cheyne-Stokes respiration, cyanosis), extreme somnolence progressing to stupor or coma, skeletal muscle flaccidity, cold and clammy skin, constricted pupils and sometimes bradycardia and hypotension. In severe overdosage, apnea, circulatory collapse, cardiac arrest and death may occur.

OPANA ER may cause 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 origin may produce similar findings). Marked mydriasis rather than miosis may be seen with hypoxia in overdose situations (see CLINICAL PHARMACOLOGY: Central Nervous System).

Treatment

In the treatment of OPANA ER overdosage, primary attention should be given to the re-establishment of a patent airway and institution of assisted or controlled ventilation. Supportive measures (including oxygen and vasopressors) should be employed in the management of circulatory shock and pulmonary edema accompanying overdose as indicated. Cardiac arrest or arrhythmias may require cardiac massage or defibrillation. Elimination or evacuation of gastric contents may be necessary in order to eliminate unabsorbed drug. Before attempting treatment by gastric emptying or activated charcoal, care should be taken to secure the airway.

The opioid antagonist naloxone hydrochloride is a specific antidote against respiratory depression, which may result from overdosage or unusual sensitivity to opioids including OPANA ER. Therefore, an appropriate dose of naloxone hydrochloride should be administered (usual initial adult dose 0.4 mg-2 mg) preferably by the intravenous route and simultaneously with efforts at respiratory resuscitation. Nalmefene is an alternative pure opioid antagonist, which may be administered as a specific antidote to respiratory depression resulting from opioid overdose. Since the duration of action of OPANA ER may exceed that of the antagonist, the patient should be kept under continued surveillance and repeated doses of the antagonist should be administered according to the antagonist labeling as needed to maintain adequate respiration.

In patients receiving OPANA ER, opioid antagonists should not be administered in the absence of clinically significant respiratory or circulatory depression secondary to OPANA ER overdose. They should be administered cautiously to persons who are known, or suspected to be, physically dependent on any opioid agonist including OPANA ER. In such cases, an abrupt or complete reversal of opioid effects may precipitate an acute abstinence syndrome. In an individual physically dependent on opioids, administration of the usual dose of the antagonist will precipitate an acute withdrawal syndrome. The severity of the withdrawal syndrome produced will depend on the degree of physical dependence and the dose of the antagonist administered. If respiratory depression is associated with muscular rigidity, administration of a neuromuscular blocking agent may be necessary to facilitate assisted or controlled ventilation. Muscular rigidity may also respond to opioid antagonist therapy.

Initiation of Therapy

Individualization of Dose

Once therapy is initiated, pain relief and other opioid effects should be frequently assessed. In clinical practice, titration of the total daily OPANA ER dose should be based upon the amount of supplemental opioid utilization, severity of the patient’s pain, and the patient’s ability to tolerate the opioid. Patients should be titrated to generally mild or no pain with the regular use of no more than two doses of supplemental analgesia, i.e. “rescue,” per 24 hours.

If signs of excessive opioid-related adverse experiences are observed, the next dose may be reduced. If this adjustment leads to inadequate analgesia, a supplemental dose of OPANA, another immediate-release opioid, or a non-opioid analgesic may be administered. Dose adjustments should be made to obtain an appropriate balance between pain relief and opioid-related adverse experiences. If significant adverse events occur before the therapeutic goal of mild or no pain is achieved, the events should be treated aggressively. Once adverse events are under control, upward titration should continue to an acceptable level of pain control.

During periods of changing analgesic requirements, including initial titration, frequent contact is recommended between physician, other members of the healthcare team, the patient and the caregiver/family. Patients and caregivers/family members should be advised of the potential side effects.

Patients with Hepatic Impairment

Patients with mild hepatic impairment should be started with the lowest dose and titrated slowly while carefully monitoring side effects. OPANA ER is contraindicated in patients with moderate and severe hepatic dysfunction (see CLINICAL PHARMACOLOGY,CONTRAINDICATIONS and PRECAUTIONS).

Patients with Renal Impairment

There are 57% and 65% increases in oxymorphone bioavailability in patients with moderate and severe renal impairment, respectively (seeCLINICAL PHARMACOLOGY and PRECAUTIONS). Accordingly, in patients with creatinine clearance rate less than 50 mL/min, OPANA ER should be started with the lowest dose and titrated slowly while carefully monitoring side effects.

Use with CNS Depressants

OPANA ER, like all opioid analgesics, should be started at 1/3 to 1/2 of the usual dose in patients who are concurrently receiving other central nervous system depressants including sedatives or hypnotics, general anesthetics, phenothiazines, tranquilizers, and alcohol because respiratory depression, hypotension, and profound sedation or coma may result. No specific interaction between oxymorphone and monoamine oxidase inhibitors has been observed, but caution in the use of any opioid in patients taking this class of drugs is appropriate (seePRECAUTIONS: General and PRECAUTIONS: Drug-Drug Interactions).

Geriatrics

The steady-state plasma concentrations of oxymorphone are approximately 40% higher in elderly subjects than in young subjects (seeCLINICAL PHARMACOLOGY and PRECAUTIONS). In general, caution should be exercised in the selection of the starting dose of OPANA ER for an elderly patient usually starting at the low end of the dosing range and slowly titrating to adequate analgesia.

Maintenance of Therapy and Supplemental Analgesia

The intent of the titration period is to establish a patient-specific every 12 hours dose that will maintain adequate analgesia with acceptable side effects for as long as pain relief is necessary. During titration and before a stable dose is achieved, OPANA or other immediate-release medications can be used as supplemental analgesia between dosings. Should pain recur, the dose can be incrementally increased to re-establish pain control. The method of therapy adjustment outlined above should be employed to re-establish pain control.

During chronic therapy with OPANA ER, the continued need for around-the-clock opioid therapy should be reassessed periodically.

Cessation of Therapy

When the patient no longer requires therapy with OPANA ER tablets, doses should be tapered gradually to prevent signs and symptoms of withdrawal in the physically dependent patient (seeCLINICAL TRIALS: 12-Week Study in Opioid-Naïve Patients with Low Back Pain and CLINICAL TRIALS: 12-Week Study in Opioid-Experienced Patients with Low Back Pain).

Read the Patient Information that comes with OPANA ER before you start taking it and each time you get a new prescription. There may be new information. This information does not take the place of talking with your healthcare provider about your medical condition or your treatment. Share the important information in this leaflet with members of your household.

What Is the Most Important Information I Should Know About OPANA ER?

• OPANA ER can cause trouble breathing (hypoventilation), which can lead to death, if used differently than the way you were told to use it by your healthcare provider (see “What are the possible side effects of OPANA ER?”).
  
  
• Swallow OPANA ER tablets whole. Do not break, crush, dissolve, or chew OPANA ER tablets before swallowing. If a tablet is broken, crushed, dissolved, or chewed, the full 12 hour dose can be taken into your body all at once. This is very dangerous. You could die from an overdose of the medicine. Use OPANA ER exactly the way your healthcare provider prescribes. If you cannot swallow tablets whole, tell your healthcare provider. You may need a different medicine.

What is OPANA ER?

• OPANA ER is a prescription medicine that contains the opioid (narcotic pain medicine) oxymorphone. OPANA ER is used to treat adults with constant pain (around the clock) that is moderate to severe and is expected to last for an extended period of time. OPANA ER is not for occasional (“as needed”) use.
  
  
• OPANA ER can cause physical dependence. Do not stop taking OPANA ER all of a sudden if you have been taking it for more than a few days. You could become sick with uncomfortable withdrawal symptoms because your body has become use to the medicine. Talk to your healthcare provider about slowly stopping OPANA ER to avoid getting sick with withdrawal symptoms. Physical dependence is not the same as drug addiction. Your healthcare provider can tell you more about the differences between physical dependence and drug addiction.
  
  
• OPANA ER is a controlled substance (CII) because it contains a narcotic painkiller that can be a target for people who abuse prescription medicines or street drugs. Keep your tablets in a safe place to protect them from being stolen. Never give your tablets to anyone else, even if they have the same symptoms you have. Selling or giving away this medicine may harm others, even causing death, and is against the law.

Who Should Not Take OPANA ER?
Do not take OPANA ER if:

• You had surgery within the past day (24 hours) and you were not taking OPANA ER before your surgery.
  
  
• Your pain is mild or will go away in a few days.
  
  
• Your pain can be controlled by the occasional use of other pain medicines.
  
  
• You are having an asthma attack or have severe asthma, trouble breathing, or lung problems.
  
  
• You have liver problems.
  
  
• You are allergic to OPANA ER or anything in it. See the end of this leaflet for a complete list of ingredients in OPANA ER.

You have had severe allergic reactions to other narcotic pain medicines (such as morphine or codeine medicines). A severe allergic reaction includes a severe rash, hives, breathing problems, or dizziness.

OPANA ER is not for children under 18 years of age.

What Should I Tell My Healthcare Provider Before Starting OPANA ER?
Tell your healthcare provider about all of your medical problems, especially if you:

• have trouble breathing or lung problems
  
  
• have a head injury or brain problem
  
  
• have liver or kidney problems
  
  
• have adrenal gland problems, such as Addison’s disease
  
  
• have convulsions or seizures
  
  
• have thyroid problems
  
  
• have problems urinating or prostate problems
  
  
• have pancreas problems
  
  
• have a drinking problem or alcoholism
  
  
• have severe mental problems or hallucinations (see or hear things that are not really there)
  
  
• have past or present drug abuse or drug addiction problems
  
  
• are pregnant or plan to become pregnant. OPANA ER may harm your unborn baby.
  
  
• are breastfeeding. OPANA ER may pass through your milk and may harm your baby. You should not breastfeed while taking OPANA ER.

Tell your healthcare provider about all the medicines you take, including prescription and nonprescription medicines, vitamins, and herbal supplements. Some medicines may cause serious problems when taken with OPANA ER, especially if they cause sleepiness (like sleeping pills, anxiety medicines, antihistamines, or tranquilizers).

Do not take any new medicines while using OPANA ER until you have talked to your healthcare provider or pharmacist and they have told you it is safe.

Know the medicines you take. Keep a list of them to show your healthcare provider and pharmacist.

How Should I Take OPANA ER?

• Follow your healthcare provider’s directions exactly. Your healthcare provider may change your dose based on your reactions to the medicine. Do not change your dose unless your healthcare provider tells you to change it. Do not take OPANA ER more often than prescribed.
  
  
• Swallow OPANA ER tablets whole. Do not break, crush, dissolve, or chew OPANA ER tablets before swallowing. If a tablet is broken, crushed, dissolved, or chewed, the full 12 hour dose can be taken into your body all at once. This is very dangerous. You could die from an overdose of the medicine. If you cannot swallow tablets whole, tell your healthcare provider. You may need a different medicine.
  
  
• Take OPANA ER every 12 hours or as instructed by your healthcare provider. OPANA ER should be taken on an empty stomach, at least one hour before or two hours after meals. Talk to your healthcare provider if you feel sick taking OPANA ER on an empty stomach.
  
  
• If you miss a dose, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once unless your healthcare provider tells you to. If you are not sure about your dosing call your healthcare provider.
  
  
• If you take too much OPANA ER or overdose, call your local emergency number or poison control center right away.
  
  
• Talk to your healthcare provider often about your pain. Your healthcare provider can decide if you still need OPANA ER.
  
  
• If you have side effects that bother you or if you continue to have pain, call your healthcare provider.
  
  
• Stopping OPANA ER. If your healthcare provider decides you no longer need OPANA ER, ask how to slowly reduce the dose of your medicine so you don’t get uncomfortable (withdrawal) symptoms such as nausea, sweating, and pain. You should not stop taking OPANA ER all at once if you have been taking it for more than a few days without talking to your healthcare provider. OPANA ER can cause physical dependence. You can get sick with withdrawal symptoms if you stop OPANA ER all at once, because your body has become use to it.

After you stop taking OPANA ER, flush the unused tablets down the toilet. Safely dispose of OPANA ER out of the reach of children and pets.

What Should I Avoid While Taking OPANA ER?

• Do not drive, operate heavy machinery, or participate in any other possibly dangerous activities until you know how you react to this medicine. OPANA ER can make you sleepy. Ask your healthcare provider to tell you when it is okay to do these activities.
  
  
• Do not drink alcohol while using OPANA ER. It may increase the chance of having dangerous side effects including overdose and death.

What are the Possible Side Effects of OPANA ER?
OPANA ER can cause trouble breathing.
Call your healthcare provider or get medical help right away if:

• your breathing slows down
  
  
• you have shallow breathing (little chest movement with breathing)
  
  
• you feel faint, dizzy, confused, or have any other unusual symptoms

These can be signs that you have taken too much OPANA ER (overdose) or the dose is too high for you, which can be dangerous and lead to death if not treated.

OPANA ER can cause your blood pressure to drop. This can make you feel dizzy if you get up too fast from sitting or lying down. Low blood pressure is also more likely to happen if you are taking other medicines that can also lower your blood pressure.

OPANA ER can cause physical dependence. Your body will get used to OPANA ER if you take it more than a few days. You can get sick with withdrawal symptoms if you stop taking OPANA ER all at once. You can avoid getting sick with withdrawal symptoms by stopping OPANA ER slowly. Your healthcare provider will tell you how to do this.

There is a chance of abuse or addiction with OPANA ER. Abuse or addiction is different than a physical dependence. If you have abused prescription medicines, street drugs or alcohol in the past, you may have a higher chance of developing abuse or addiction again while using OPANA ER. If you have more concerns, talk to your healthcare provider for more information about abuse and addiction.

The most common side effects of OPANA ER are nausea, constipation, dizziness, vomiting, itching, sleepiness, headache, increased sweating, and sedation. Some of these side effects may decrease with continued use. Talk to your healthcare provider if you continue to have these side effects.

These are not all the possible side effects of OPANA ER. For a complete list, ask your healthcare provider or pharmacist.

Constipation (decrease in the usual number of hard bowel movements) is a common side effect of opioid medicines, including OPANA ER. Talk to your healthcare provider or pharmacist about the use of laxatives (medicines to treat constipation) and stool softeners to prevent or treat constipation while taking OPANA ER.

How should I store OPANA ER?

• Store OPANA ER at room temperature between 59° to 86°F (15° to 30°C).
  
  
• Keep OPANA ER in a childproof container and store in a safe place to protect it from being stolen.
  
  
• Keep OPANA ER out of the reach of children. Accidental overdose in children is an emergency and can result in death.

General Information about OPANA ER

• Do not use OPANA ER for conditions for which it was not prescribed.
  
  
• Do not give OPANA ER to other people, even if they have the same symptoms you have. It may harm them, even causing death, and it is against the law.

This leaflet summarizes the most important information about OPANA ER. If you would like more information, talk with your healthcare provider. Also, you can ask your pharmacist or healthcare provider for information about OPANA ER that is written for healthcare professionals.

For additional information, please go to www.Endo.com or www.opana.com

What are the ingredients in OPANA ER?
Active Ingredient: oxymorphone hydrochloride
Inactive Ingredients: hypromellose, iron oxide black, methylparaben, propylene glycol, silicified microcrystalline cellulose, sodium stearyl fumarate, TIMERx®-N, titanium dioxide, and triacetin. The 5 mg, 10 mg and 20 mg tablets also contain macrogol, and polysorbate 80. In addition, the 5 mg tablets contain iron oxide red. The 10 mg tablets contain FD&C yellow No. 6. The 20 mg tablets contain FD&C blue No. 1, FD&C yellow No. 6, and D&C yellow No. 10. The 40 mg tablets contain FD&C yellow No. 6, D&C yellow No.10, and lactose monohydrate.

CAUTION: Federal law prohibits dispensing without prescription.

Manufactured for:
Endo Pharmaceuticals Inc.
Chadds Ford, Pennsylvania 19317

Manufactured by:
Novartis Consumer Health Inc.
Lincoln, NE 68517

Repackaged by:

Rebel Distributors Corp

Thousand Oaks, CA 91320

TIMERx®-N is a registered Trademark of Penwest Pharmaceuticals Co., Danbury, Connecticut and is used herein pursuant to a license agreement between Penwest and Endo Pharmaceuticals.

                                                                 Copyright © Endo Pharmaceuticals Inc. 2006

                                                                                                            413442/June, 2006