Anesthetic considerations for the new antiobesity medications.

Combination drug therapy can effectively treat the problem of obesity. The most commonly used combination is a mix of fenfluramine and phentermine. Fenfluramine inhibits the reuptake of serotonin and acts on the hypothalmic appetite control center, while phentermine acts as an appetite suppressant. These drugs along with diet and exercise effectively help people to lose weight with few side effects. However, there are several anesthetic considerations when providing anesthesia services for patients on the fenfluramine and phentermine regimen. Problems of hypotension on induction, hypoglycemia, hyperthermia, and pulmonary hypertension have been reported in the literature. Recently, dexfenfluramine (Redux) was approved by the U.S. Food and Drug Administration. It is the dextrostereoisomer of fenfluramine and is believed to produce the same weight loss with less side effects. Anesthesia providers must understand the potential risks involved when administering a general anesthetic to these patients.