Which listed medication fails to have approval for weight management due to low efficacy?

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

Answer: (C)

Weight management drugs are approved only when trials show a meaningful amount of weight loss beyond placebo. Lisdexamfetamine has not demonstrated sufficient efficacy for obesity treatment in those trials, so it does not have FDA approval for weight management. The other medications have shown approved benefits for weight loss: orlistat reduces fat absorption with modest weight loss, phentermine is approved for short-term use in adults as an appetite suppressant, and liraglutide (at the higher obesity-dose) has demonstrated meaningful weight loss and is approved for obesity in adults and certain adolescents. So, the medication without approval for weight management due to insufficient efficacy is lisdexamfetamine.