Moderation of Prazosin's Efficacy by Alcohol Withdrawal Symptoms

Alcohol use disorder (AUD) is a leading cause of global disease burden. Chronic, heavy use increases the likelihood of alcohol withdrawal symptoms and associated secondary outcomes of alcohol craving and mood, anxiety, and sleep disturbances, which are predictive of poor treatment outcomes. The authors examined whether alcohol withdrawal symptoms moderate the efficacy of prazosin in reducing alcohol intake and associated secondary outcomes.

A 12-week, double-blind, randomized, controlled proof-of-concept trial of prazosin (16 mg/day, with a 2-week titration) was conducted in community-recruited adults with current alcohol dependence (N=100) with varying levels of alcohol withdrawal symptoms assessed at treatment entry. Primary outcomes were daily self-reported drinking days and heavy drinking days, and secondary outcomes were average drinks/day and mood, anxiety, craving, and sleep quality ratings.

Modified intent-to-treat analyses indicated a significant interaction of alcohol withdrawal symptom score by treatment by full-dose treatment period (weeks 3-12) for drinking days, heavy drinking days, and average drinks/day. By week 12, participants with high alcohol withdrawal symptoms on prazosin reported 7.07% heavy drinking days and 27.46% drinking days, while those on placebo had 35.58% heavy drinking days and 58.47% drinking days (heavy drinking days: odds ratio=0.14, 95% CI=0.058, 0.333; drinking days: odds ratio=0.265, 95% CI=0.146, 0.481). No such benefit of prazosin was observed in those reporting low or no alcohol withdrawal symptoms. Individuals with high alcohol withdrawal symptoms on prazosin compared with placebo also showed significantly improved anxiety, depression, and alcohol craving over the course of the trial.

The findings indicate that alcohol withdrawal symptoms are a significant moderator of prazosin treatment response for alcohol use outcomes and for associated symptoms of alcohol craving, anxiety, and mood symptoms. These data support further evaluation of alcohol withdrawal symptoms as a prognostic indicator of prazosin's efficacy in the treatment of AUD.