Alcohol Urge and Plasma beta-endorphin Change after Alcohol Challenge in Naltrexone Pretreated Social Drinker

Kim, Eun Hee; Sohn, In Ki; Lee, Young Sik; Na, Chul

Abstract

OBJECTIVES
The present study was performed to evaluate whether naltrexone treatment are effectively lowering the urge of alcohol drinking, and to investigate the its mechanism of action.
METHODS
15 healthy male social drinkers were voluntarily participated. The experimental method was double-blind placebo-controlled cross over design. Subjects ingested a naltrexone (50mg)/day or placebo for 1 week. Plasma beta-endorphin, plasma ACTH and serum cortisol levels were measured before, at 20 minutes and at 60 minutes after alcohol exposure. Subjects completed self-report questionnaires such as the visual analog scales of drink urge and the alcohol sensation scales at regular intervals.
RESULTS
1) During naltrexone pretreatment period, subjects reported more headache, dizziness, nervousness, fatigue, day somnolence, nausea, and decreased appetite than placebo pretreatment period. But serum GOT/GPT levels were not significantly different between two pretreatment periods. 2) In case of naltrexone pretreatment, subjects reported significantly less urge to alcohol drink on the self-reporting urge scales, especially at post-drinking 20 minutes and 60 minutes than placebo pretreatment. 3) After alcohol challenge, subjects reported significantly more dizziness on the alcohol sensation scales in case of naltrexone pretreatment, and reported less mood elevation trend though it was not statistically significant. Other scores were not significantly different between two pretreatments. 4) Plasma beta-endorphin levels were significantly different when treated with naltrexone. In case of naltrexone-pretreatment, the increasing degree of plasma beta-endorphin during 20 minutes after alcohol challenge was significantly higher than placebo pretreatment. 5) Basal plasma ACTH level and basal serum cortisol level were not significantly different between two pretreatments. After alcohol challenge, only the decreasing degree of plasma ACTH levels during 20 minutes was significantly lowered in the naltrexone pretreatment than placebo pretreatment.
CONCLUSIONS
Naltrexone reduced urge to alcohol drinking in social drinker. The action mechanism of naltrexone may be partially blocking opioid positive reward system and partially alcohol mimicking its property.