Contrave, is the latest weight-loss drug to be approved by the FDA (11/09/2014) for adults who are obese. Contrave is also approved for those not obese but overweight with risk factors such as high blood pressure, high cholesterol, or diabetes.
 BRAND NAMES
 MECHANISM OF ACTION
- Naltrexone is an opioid antagonist used to combat alcohol and opioid dependence
- Bupropion, an aminoketone antidepressant, is 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 Naltrexone/Bupropion tablets leading to weight loss are not fully understood.
Patients on Naltrexone/Bupropion (Contrave) for a year lost 4.1 percent more weight than patients taking a dummy pill (Placebo). 42 percent of patients treated with Naltrexone/Bupropion (Contrave) lost at least 5 percent of their body weight compared with 17 percent of patients treated with placebo.
Naltrexone/Bupropion tablets are 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).
Patients using Naltrexone/Bupropion (Contrave) at the maintenance dose should be evaluated after 12 weeks to determine if the treatment is working. If a patient has not lost at least 5 percent of baseline body weight, Naltrexone/Bupropion (Contrave) should be discontinued
Limitations of Use:
- The effect of Naltrexone/Bupropion tablets on cardiovascular morbidity and mortality has not been established.
- The safety and effectiveness of Naltrexone/Bupropion tablets in combination with other products intended for weight loss, including prescription and over-the-counter drugs, and herbal preparations, have not been established.
- Naltrexone/Bupropion (Contrave) has not been studied in and is not approved for use in children under the age of 18.
 DOSAGE FORMS AND STRENGTHS
CONTRAVE extended-release tri-layer tablets, 8 mg/90 mg, are blue, round, bi-convex, film-coated, and debossed with “NB-890” on one side.
- Uncontrolled hypertension: Naltrexone/Bupropion (Contrave) can raise blood pressure and heart rate and must not be used in patients with uncontrolled high blood pressure.
- Seizure disorders, anorexia nervosa or bulimia, or undergoing abrupt discontinuation of alcohol, benzodiazepines, barbiturates, and antiepileptic drugs
- Use of other bupropion-containing products such as Wellbutrin, Wellbutrin SR, Wellbutrin XL and Aplenzin
- Chronic opioid use
- During or within 14 days of taking monoamine oxidase inhibitors (MAOI)
- Known allergy to any of the ingredients
 WARNINGS AND PRECAUTIONS
- Suicidal Behavior and Ideation: Bupropion may increase suicidal thoughts or actions in some children, teenagers, and young adults within the first few months of treatment. Monitor for depression or suicidal thoughts. Discontinue Naltrexone/Bupropion tablets (Contrave) if symptoms develop.
- 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.
- MAOIs: Increased risk of hypertensive reactions can occur when used concomitantly. 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 Naltrexone/Bupropion (Contrave). Conversely, at least 14 days should be allowed after stopping Naltrexone/Bupropion (Contrave) before starting an MAOI
- Drugs Metabolized by CYP2D6: Bupropion inhibits CYP2D6 and can increase concentrations of: antidepressants, (e.g., selective serotonin reuptake inhibitors and many tricyclics), antipsychotics (e.g., haloperidol, risperidone and thioridazine), beta-blockers (e.g., metoprolol) and Type 1C antiarrhythmics (e.g., propafenone and flecainide): Consider dose reduction when using with Naltrexone/Bupropion (Contrave).
- Concomitant Treatment with CYP2B6 Inhibitors (e.g., ticlopidine or clopidogrel) can increase bupropion exposure. Do not exceed one tablet twice daily when taken with CYP2B6 inhibitors.
- CYP2B6 Inducers (e.g., ritonavir, lopinavir, efavirenz, carbamazepine, phenobarbital, and phenytoin) may reduce efficacy by reducing bupropion exposure, avoid concomitant use.
- Drugs that Lower Seizure Threshold (e.g., antipsychotics, antidepressants, theophylline, or systemic corticosteroids): Dose Naltrexone/Bupropion (Contrave) with caution.
- 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 Naltrexone/Bupropion (Contrave) concomitantly with these drugs.
- Drug -Laboratory Test Interactions: Naltrexone/Bupropion (Contrave) can cause false positive urine test results for amphetamines.
 PREGNANCY AND LACTATION
- Pregnancy Category X (US). Naltrexone/Bupropion (Contrave) is contraindicated during pregnancy, because weight loss offers no potential benefit to a pregnant woman and may result in fetal harm. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard of maternal weight loss to the fetus. A minimum weight gain, and no weight loss, is currently recommended for all pregnant women, including those who are already overweight or obese, due to the obligatory weight gain that occurs in maternal tissues during pregnancy.
- Nursing Mothers: Discontinue drug or nursing.
 SIDE EFFECTS
Most common adverse reactions (greater than or equal to 5%): nausea, constipation, headache, vomiting, dizziness, insomnia, dry mouth and diarrhea.
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