Key takeaways
Contrave (naltrexone / bupropion) and Adipex-P (phentermine) are both medications used to help with weight loss in adults with a high body mass index (BMI) and weight-related conditions. However, they belong to different medication classes and have distinct mechanisms of action. Contrave combines an opioid antagonist (naltrexone) and a dopamine and norepinephrine reuptake inhibitor (bupropion) to help control appetite and cravings. In contrast, Adipex-P is a sympathomimetic stimulant that suppresses appetite. Contrave is taken as a tablet twice daily after taking it once daily for a week or more, while Adipex-P is typically taken once daily in the morning. Contrave is not available as a generic, whereas Adipex-P is available as a lower-cost generic. Common side effects of Contrave include nausea and headache, and rare but serious risks include seizures and mood changes. Adipex-P can cause dry mouth and trouble sleeping, with risks of high blood pressure and dependence. Contrave should not be taken with opioids due to the possibility of withdrawal. Adipex-P is a controlled substance due to its potential for misuse.
