Pharmacologic Weight Loss Therapy

Weight loss drugs approved by the U.S. Food and Drug Administration (FDA) may be useful as an adjunct to diet and physical activity for patients with a BMI ≥ 30 and without concomitant obesity-related risk factors or diseases. Drug therapy may also be useful for patients with a BMI ≥ 27 who also have concomitant obesity-related risk factors or diseases. The FDA approved medications are intended to assist obese and overweight Americans who have been unsuccessful in getting their weight under control with diet and exercise.

Short-term weight loss medications are indicated as adjunct therapy in a regimen of weight reduction based on exercise, behavioral modification and caloric restriction.

• Phentermine hydrochloride is an anorectic and weak noradrenergic sympathomimetic that induces appetite suppression presumably by CNS stimulation. Phentermine is chemically related to amphetamine, but does not have the same addictive potential. Phentermine is listed as a Schedule IV drug (along with other drugs such as barbiturates, benzodiazepines etc.) because it has a low potential for abuse, and because it has a medical use for short-term treatment of obesity. Prescribed use of phentermine is approved for up to 3 months.
  

Long-term weight loss medication may be required for the rest of a patient's life to augment weight loss from diet and behavioral changes.

• Sibutramine is no longer available in the U.S. Sibutramine may increase risk of cardiovascular events such as heart attack and stroke for some patients.
• Orlistat (Xenical) is approved for use in adults and children 12 and older. Orlistat inhibits pancreatic lipase. Decreased lipase action reduces the digestion and absorption of fat in the stomach and intestines. Unabsorbed fat is eliminated in the stool. Decrease fat absorption can result in a deficit of fat-soluble vitamins; soft stools and oily anal leakage. After one to two years of use, Orlistat averages only about 5 to 7 pounds more than expected weight loss from diet and exercise. The FDA has issued warnings for Orlistat (Xenical) due to reports of severe liver injury with hepatocellular necrosis or acute hepatic failure. If liver injury is suspected, orlistat and other suspect medications should be discontinued immediately and liver function tests and ALT and AST levels obtained. FDA Clinical Review
• Lorcaserin (Belviq) is a centrally acting, selective serotonin 2C agonist approved for weight management in conjunction with a reduced-calorie diet and a program of regular exercise. Lorcaserin decreases food consumption by selectively mimicking the effects of serotonin at the 5-HT2C receptor. Serotonin reduces pre-meal hunger and increases meal-related satiety. In placebo controlled studies, approximately 23% of subjects in the placebo groups lost > 5% of baseline body weight during Year 1 compared with 47% and 40% of subjects in the lorcaserin 10 mg BID and lorcaserin 10 mg QD groups, respectively (p<0.001 both lorcaserin vs. placebo). FDA label information
• Qsymia™ is an extended-release combination of two FDA-approved drugs, phentermine and topiramate. Phentermine is approved for short-term weight loss in overweight or obese adults who are exercising and eating a reduced calorie diet. Topiramate is indicated to treat certain types of seizures in people who have epilepsy and to prevent migraine headaches. FDA label information
  The FDA approved Qsymia with a Risk Evaluation and Mitigation Strategy (REMS), which consists of a Medication Guide advising patients about important safety information and elements to assure safe use that include prescriber training and pharmacy certification. The purpose of the REMS is to educate prescribers and their patients about the increased risk of birth defects associated with first trimester exposure to Qsymia, the need for pregnancy prevention, and the need to discontinue therapy if pregnancy occurs. Qsymia will only be dispensed through specially certified pharmacies.

Placebo-controlled studies indicate that a statistically significant proportion of the patients benefit from the addition of weight loss medication to a low energy diet and exercise regimen. These studies also indicate that many patients are unable to complete these studies. Most patients will have intermittent success with weight loss. For these patients surgery may be an appropriate means of safe weight loss.

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