Naltrexone decreases heavy drinking rates in smoking cessation treatment: an exploratory study.

BACKGROUND There is mixed support for the efficacy of the opioid antagonist naltrexone in the treatment of nicotine dependence. One potential unexplored mechanism underlying naltrexone's effects in smoking cessation may be in its ability to reduce alcohol consumption. METHODS Alcohol consumption and liver enzyme levels (aspartate aminotransferase and alanine transaminase) were examined in a sample of 78 nonalcoholic social drinking smokers (34 naltrexone, 44 placebo) enrolled in a double-blind randomized clinical trial of naltrexone in smoking cessation. Naltrexone or placebo began 3 days prior to the quit date (25 mg daily) and continued for 8 weeks (50 mg daily). All participants received nicotine patches and behavioral counseling up through 4 weeks after the quit date. RESULTS Naltrexone significantly reduced weekly heavy drinking rates. This effect was associated with greater nausea and pill taking adherence within the naltrexone group. Within heavy drinkers, naltrexone also directionally improved smoking quit rates compared with placebo. Liver enzyme levels did not differ during treatment with naltrexone compared with placebo. CONCLUSIONS Naltrexone may reduce the frequency of heavy drinking in nonalcoholics attempting to quit smoking. Further, naltrexone may preferentially improve smoking quit rates within heavy drinkers who smoke, and further investigation in larger sample sizes is warranted.