Pharmacologic interventions. The search for safe and effective pharmacologic agents for weight loss has been problematic. Because of a growing list of associated serious cardiovascular adverse effects, the U.S. Food and Drug Administration (FDA) withdrew both the combination fenfluramine–phentermine (known as fen-phen) and the drug sibutramine (Meridia) years after their initial approval as weight loss aids. Lorcaserin (Belviq) is, like fenfluramine, a serotonin receptor agonist, though it is thought to carry a lower risk of valvular heart disease than fenfluramine. The FDA reports, however, that 2.4% of adults in clinical trials developed valvular regurgitation while using the drug compared with 2% of those treated with placebo.