Naltrexone. The drug naltrexone (Trexan) blocks the euphoria of drug abusers and is being tested for people who binge. Its effects have been promising. (The drug has no effect on people who do not binge.) It is, unfortunately, available only by injection.

Leptin. Preliminary results from early studies on the use of daily injections of genetically engineered leptin are reporting weight loss among some genetically obese subjects. Higher doses may be needed for higher weights. The most common side effects were pain at the injection site and headache. There appear to be no significant adverse effects on major organs, including the heart, liver, kidney, central nervous system, or gastrointestinal tract. It also does not appear to affect insulin levels, a previous concern.

Neuropeptide Y. Neuropeptide Y is a powerful appetite-stimulating chemical in the brain. Agents are being investigated that block this peptic.

Note on Redux and Other Serotonin-Releasing Anorexiants
Dexfenfluramine (Redux), fenfluramine (Pondimin), and the combination drug commonly called fen-phen (phentermine/fenfluramine) are known as serotonin-releasing anorexiants are agents. They produce weight loss by increasing the availability of serotonin, a chemical in the brain that prevents depression and reduces calorie consumption. Unfortunately, very serious side effects were reported with their use, especially development of abnormalities in the valves of the heart and, uncommonly, a potentially life-threatening condition called pulmonary hypertension. They have now been pulled from the market. (Phentermine, the second agent in fen-phen is still available as a weight-loss agent and does not appear to have adverse the adverse effects of these other drugs).

As of the date of this report, patients who had developed valve damage have either improved or experienced no progression of the problem.