Identify the medication that is not approved for weight management because of low efficacy.

• A. Orlistat
• B. Phentermine
• C. Lisdexamfetamine
• D. Liraglutide

Answer: (C)

Medications for weight management are approved only when trials show meaningful, durable weight loss with an acceptable safety profile. Lisdexamfetamine, while effective for ADHD and for binge eating disorder in some cases, has not demonstrated enough weight loss benefit in obesity-focused studies to justify approval for weight management. The gains tend to be modest, and safety concerns typical of stimulants—such as potential for misuse and cardiovascular effects—make regulators hesitant to approve it for chronic weight management. In contrast, options like orlistat, phentermine, and liraglutide have shown more substantial and clinically meaningful weight reduction in trials and are approved for this purpose. That’s why lisdexamfetamine is the one not approved for weight management due to low efficacy.