CONTRAVE (naltrexone hydrochloride and bupropion hydrochloride) extended-release tablets

CONTRAVE (naltrexone hydrochloride and bupropion hydrochloride) extended-release tablets

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CONTRAVE (naltrexone hydrochloride and bupropion hydrochloride) extended-release tablets

CONTRAVE extended-release tablets contain naltrexone hydrochloride (HCl) and bupropion HCl.

Naltrexone HCl, USP, an opioid antagonist, is a synthetic congener of oxymorphone with no opioid agonist properties. Naltrexone differs in structure from oxymorphone in that the methyl group on the nitrogen atom is replaced by a cyclopropylmethyl group. Naltrexone HCl is also related to the potent opioid antagonist, naloxone, or n-allylnoroxymorphone.

Naltrexone HCl has the chemical name of morphinan-6-one, 17-(cyclopropylmethyl)-4,5- epoxy-3,14-dihydroxy-, hydrochloride, (5α)-. The empirical formula is C20H23NO4•HCl and the molecular weight is 377.86.

Bupropion HCl is an antidepressant of the aminoketone class. Bupropion HCl closely resembles the structure of diethylpropion. It is designated as (±)-1-(3 chlorophenyl)-2-[(1,1- dimethylethyl)amino]-1-propranone hydrochloride. It is related to phenylethylamines. The empirical formula is C13H18ClNO•HCl and the molecular weight is 276.2.

Indications and usage

CONTRAVE is a combination of naltrexone, an opioid antagonist, and bupropion, an aminoketone antidepressant, indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with an initial body mass index (BMI) of:

  • 30 kg/m2 or greater (obese) or
  • 27 kg/m2 or greater (overweight) in the presence of at least one weight-related comorbidity (e.g., hypertension, type 2 diabetes mellitus, or dyslipidemia)

Limitations of Use:

  • The effect of CONTRAVE on cardiovascular morbidity and mortality has not been established.
  • The safety and effectiveness of CONTRAVE in combination with other products intended for weight loss, including prescription and over-the-counter drugs, and herbal preparations, have not been established

Mechanism of Action

CONTRAVE has two components: naltrexone, an opioid antagonist, and bupropion, a relatively weak inhibitor of the neuronal reuptake of dopamine and norepinephrine. Nonclinical studies suggest that naltrexone and bupropion have effects on two separate areas of the brain involved in the regulation of food intake: the hypothalamus (appetite regulatory center) and the mesolimbic dopamine circuit (reward system). The exact neurochemical effects of CONTRAVE leading to weight loss are not fully understood.

Dosage and administration

 Morning DoseEvening Dose
Week 1 1 tabletNone
Week 21 tablet 1 tablet
Week 32 tablets1 tablet
Week 4 – Onward2 tablets2 tablets

A total daily dosage of two CONTRAVE 8 mg/90 mg tablets twice daily (32 mg/360 mg) is reached at the start of Week 4.

CONTRAVE should be taken by mouth in the morning and in the evening. The tablets should not be cut, chewed, or crushed. Total daily doses greater than 32 mg/360 mg per day (two tablets twice daily) are not recommended.

However, CONTRAVE should not be taken with a high-fat meal because of a resulting significant increase in bupropion and naltrexone systemic exposure

Patients may develop elevated blood pressure or heart rate during CONTRAVE treatment; the risk may be greater during the initial three months of therapy. Because patients with hypertension may be at increased risk for developing blood pressure elevations, such patients should be monitored for this potential effect when initiating treatment with CONTRAVE.

Response to therapy should be evaluated after 12 weeks at the maintenance dosage. If a patient has not lost at least 5% of baseline body weight, discontinue CONTRAVE, as it is unlikely that the patient will achieve and sustain clinically meaningful weight loss with continued treatment.

Switching a Patient To or From a Monoamine Oxidase Inhibitor (MAOI) Antidepressant

At least 14 days should elapse between discontinuation of an MAOI intended to treat depression and initiation of therapy with CONTRAVE. Conversely, at least 14 days should be allowed after stopping CONTRAVE before starting an MAOI antidepressant

Warnings and precautions

  • Suicidal Behavior and Ideation: Monitor for depression or suicidal thoughts. Discontinue CONTRAVE if symptoms develop.
  • Neuropsychiatric Adverse Events During Smoking Cessation: Postmarketing reports of serious or clinically significant neuropsychiatric adverse events have included changes in mood (including depression and mania), psychosis, hallucinations, paranoia, delusions, homicidal ideation, aggression, hostility, agitation, anxiety, and panic, as well as suicidal ideation, suicide attempt, and completed suicide. Observe patients taking CONTRAVE for the occurrence of such symptoms and instruct them to discontinue CONTRAVE and contact a healthcare provider if they experience such adverse events.
  • Risk of seizure may be minimized by adhering to the recommended dosing schedule and avoiding coadministration with high-fat meal.
  • Increase in Blood Pressure and Heart Rate: Monitor blood pressure and heart rate in all patients, especially those with cardiac or cerebrovascular disease.
  • Hepatotoxicity: Cases of hepatitis and clinically significant liver dysfunction observed with naltrexone exposure.
  • Angle-closure glaucoma: Angle-closure glaucoma has occurred in patients with untreated anatomically narrow angles treated with antidepressants.
  • Use of Antidiabetic Medications: Weight loss may cause hypoglycemia. Monitor blood glucose.

Contraindications

CONTRAVE is contraindicated in

  • Uncontrolled hypertension
  • Seizure disorder or a history of seizures
  • Use of other bupropion-containing products (including, but not limited to, WELLBUTRIN, WELLBUTRIN SR, WELLBUTRIN XL, APLENZIN and ZYBAN)
  • Bulimia or anorexia nervosa, which increase the risk for seizure
  • Chronic opioid or opiate agonist (e.g., methadone) or partial agonists (e.g., buprenorphine) use, or acute opiate withdrawal
  • Patients undergoing an abrupt discontinuation of alcohol, benzodiazepines, barbiturates, and antiepileptic drugs
  • Concomitant administration of monoamine oxidase inhibitors (MAOI). At least 14 days should elapse between discontinuation of MAOI and initiation of treatment with CONTRAVE. There is an increased risk of hypertensive reactions when CONTRAVE is used concomitantly with MAOIs. Starting CONTRAVE in a patient treated with reversible MAOIs such as linezolid or intravenous methylene blue is also contraindicated
  • Known allergy to bupropion, naltrexone or any other component of CONTRAVE. Anaphylactoid/anaphylactic reactions and Stevens-Johnson syndrome have been reported with bupropion.

Drug interactions

Monoamine Oxidase Inhibitors (MAOI): Concomitant use of MAOIs and bupropion is contraindicated. Bupropion inhibits the re-uptake of dopamine and norepinephrine and can increase the risk for hypertensive reactions when used concomitantly with drugs that also inhibit the re-uptake of dopamine or norepinephrine, including MAOIs. Studies in animals demonstrate that the acute toxicity of bupropion is enhanced by the MAOI phenelzine. At least 14 days should elapse between discontinuation of an MAOI and initiation of treatment with CONTRAVE. Conversely, at least 14 days should be allowed after stopping CONTRAVE before starting an MAOI

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Opioid Analgesics: Patients taking CONTRAVE may not fully benefit from treatment with opioid-containing medicines, such as cough and cold remedies, antidiarrheal preparations, and opioid analgesics. In patients requiring intermittent opiate treatment, CONTRAVE therapy should be temporarily discontinued and opiate dose should not be increased above the standard dose. CONTRAVE may be used with caution after chronic opioid use has been stopped for 7 to 10 days in order to prevent precipitation of withdrawal

Metabolized by CYP2D6: Coadministration of CONTRAVE with drugs that are metabolized by CYP2D6 isozyme including certain antidepressants (SSRIs and many tricyclics), antipsychotics (e.g., haloperidol, risperidone and thioridazine), beta-blockers (e.g., metoprolol) and Type 1C antiarrhythmics (e.g., propafenone and flecainide), should be approached with caution and should be initiated at the lower end of the dose range of the concomitant medication. If CONTRAVE is added to the treatment regimen of a patient already receiving a drug metabolized by CYP2D6, the need to decrease the dose of the original medication should be considered, particularly for those concomitant medications with a narrow therapeutic index

Digoxin: Coadministration of CONTRAVE with digoxin may decrease plasma digoxin levels. Monitor plasma digoxin levels in patients treated concomitantly with CONTRAVE and digoxin

Dopaminergic Drugs (Levodopa and Amantadine): Bupropion, levodopa, and amantadine have dopamine agonist effects. CNS toxicity has been reported when bupropion was coadministered with levodopa or amantadine. Adverse reactions have included restlessness, agitation, tremor, ataxia, gait disturbance, vertigo, and dizziness. It is presumed that the toxicity results from cumulative dopamine agonist effects. Use caution and monitor for such adverse reactions when administering CONTRAVE concomitantly with these drugs.

Use with Alcohol: In postmarketing experience, there have been rare reports of adverse neuropsychiatric events or reduced alcohol tolerance in patients who were drinking alcohol during treatment with bupropion. The consumption of alcohol during treatment with CONTRAVE should be minimized or avoided.

Use in specific populations

Pregnancy:Weight loss offers no benefit to a pregnant patient and may cause fetal harm. When a pregnancy is recognized, advise the pregnant patient of the risk to the fetus, and discontinue CONTRAVE. Available pharmacovigilance data and data from clinical trials with the individual components of CONTRAVE use in pregnant patients have not demonstrated a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes.

Appropriate weight gain based on pre-pregnancy weight is currently recommended for all pregnant patients, including those who are already overweight or obese, due to the obligatory weight gain that occurs in maternal tissues during pregnancy.

Lactation: Data from published literature report the presence of bupropion and its metabolites in human milk. Limited data from postmarketing reports with bupropion use during lactation have not identified a clear association of adverse effects on a breastfed infant (see Data). Naltrexone and its major metabolite, 6β-naltrexol, are present in human milk. There are no data on bupropion, naltrexone, or their metabolites on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for CONTRAVE and any potential adverse effects on the breastfed infant from CONTRAVE or from the mother’s underlying condition.

Pediatric Use: The safety and effectiveness of CONTRAVE in pediatric patients below the age of 18 have not been established and the use of CONTRAVE is not recommended in pediatric patients.

Renal Impairment: In a pharmacokinetic study conducted for CONTRAVE in subjects with renal impairment (mild, moderate and severe), exposure to naltrexone metabolite, 6-beta naltrexol, and bupropion metabolites, threohydrobupropion, and erythrohydrobupropion was increased. Therefore, the maximum recommended daily maintenance dose for CONTRAVE is two tablets (one tablet each morning and evening) in patients with moderate or severe renal impairment. CONTRAVE is not recommended for use in patients with end-stage renal disease.

Hepatic Impairment: In a pharmacokinetic study conducted for CONTRAVE in subjects with hepatic impairment (mild, moderate, and severe), exposure to naltrexone, bupropion, and their metabolites were increased. Therefore, the maximum recommended daily maintenance dose of CONTRAVE is two tablets (one tablet each morning and evening) in patients with moderate hepatic impairment. CONTRAVE is not recommended for use in patients with severe hepatic impairment.

Overdosage

Overdoses of up to 30 grams or more of bupropion (equivalent of up to 83 times the recommended daily dose of CONTRAVE 32 mg/360 mg) have been reported. Seizure was reported in approximately one third of all cases. Other serious reactions reported with overdoses of bupropion alone included hallucinations, loss of consciousness, mental status changes, sinus tachycardia, ECG changes such as conduction disturbances (including QRS prolongation) or arrhythmias, clonus, myoclonus, and hyperreflexia. Fever, muscle rigidity, rhabdomyolysis, hypotension, stupor, coma, and respiratory failure have been reported mainly when bupropion was part of multiple drug overdoses.

Although most patients recovered without sequelae, deaths associated with overdoses of bupropion alone have been reported in patients ingesting large doses of the drug. Multiple uncontrolled seizures, bradycardia, cardiac failure, and cardiac arrest prior to death were reported in these patients.

Overdosage Management

If over-exposure occurs, call your poison control center at 1-800-222-1222. There are no known antidotes for CONTRAVE. In case of an overdose, provide supportive care, including close medical supervision and monitoring. Consider the possibility of multiple drug overdose. Ensure an adequate airway, oxygenation, and ventilation. Monitor cardiac rhythm and vital signs. Induction of emesis is not recommended.

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