Naltrexone blockade of nicotine effects in cigarette smokers.
BACKGROUND
The role of endogenous opiate systems in cigarette smoking remains unclear. In laboratory animals, opiate antagonists block many of the effects of nicotine, but in humans they do not consistently alter smoking behavior.


OBJECTIVE
This study explored the effects of naltrexone, alone and in combination with nicotine, on smoking behavior.


METHODS
In a double-blind, double-dummy, within-subjects design, 19 regular smokers received four treatments of 1 week duration: naltrexone tablet (50 mg) plus placebo skin patch, placebo tablet plus nicotine skin patch (21 mg/24 h), naltrexone tablet plus nicotine skin patch, and placebo tablet plus placebo skin patch. During each treatment, subjects rated their responses to nicotine-containing and denicotinized cigarettes in the laboratory, and to their own brand of cigarette smoked ad libitum outside the laboratory.


RESULTS
Pretreatment with the nicotine patch attenuated smoking-induced decreases in craving, negative affect, and rates of ad lib smoking, and potentiated the aversiveness of a cigarette. Naltrexone reversed these effects of the nicotine patch, and produced negative effects on mood.


CONCLUSIONS
The blockade of nicotine's effects by naltrexone supports a role for opioid mechanisms in cigarette smoking.
Brauer
L H
LH
Department of Psychiatry, Duke University Medical Center, Durham, NC 27710, USA. lbrauer@acpub.duke.edu
Behm
F M
FM
Westman
E C
EC
Patel
P
P
Rose
J E
JE
D000328:Adult; D000339:Affect / Q000187:drug effects; D000704:Analysis of Variance; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009271:Naltrexone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D009538:Nicotine / Q000037:antagonists & inhibitors*; D010919:Placebos; D012907:Smoking / Q000097:blood / Q000503:physiopathology* / Q000523:psychology*; D013375:Substance Withdrawal Syndrome / Q000209:etiology / Q000517:prevention & control; D011795:Surveys and Questionnaires
D009292:Narcotic Antagonists; D010919:Placebos; D009271:Naltrexone; D009538:Nicotine