Long-acting opioid antagonist nalmefene has shown some promise in helping pathologic gamblers overcome their addiction. A recent study, reported in the American Journal of Psychiatry, randomized 207 pathologic gamblers to 25, 50, or 100 mg/day of either nalmefene or placebo. The 16- week trial was completed by 24 of 51 placebo patients and 49 of 156 nalmefene patients. In the 25-mg nalmefene group, 59% were rated as "much improved" or "very much improved," compared with 34% of the placebo group. Forty-eight percent of the 50- mg group and 42% of the 100-mg group showed some response but none that was significantly different from that of the placebo group. Side effects were mild to moderate, occurring during the first week of treatment, and included nausea, dizziness, and insomnia. Two thirds of the patients did not complete the study, possibly due to the side effects, although in pathologic gambling clinical trials about half of the patients discontinued their treatment.

Ms. Farley is a freelance medical writer based in Wakefield, RI.