Anti-craving Naltrexone Injection Reduces Drinking

Efficacy of extended-release naltrexone in alcohol-dependent patients who are abstinent before treatment.

Extended-release naltrexone (XR-NTX) is a once-a-month injectable formulation that is Food and Drug Administration-approved for the treatment of alcohol dependence in patients able to abstain from alcohol before treatment initiation.

This paper presents the results of an analysis of efficacy data from a subgroup of patients with 4 days or more of voluntary abstinence before treatment initiation (n = 82) on a wide range of drinking-related outcomes.

In these patients, all of whom received counseling, the rate of abstinence was severalfold higher for XR-NTX 380 mg compared with placebo:

median time to first drink was 41 days versus 12 days, respectively;
rate of continuous abstinence at end of the study was 32% versus 11% (P = 0.02).

Extended-release naltrexone 380 mg, compared with placebo, substantially increased time to first heavy drinking event (>180 days vs 20 days; P = 0.04) and decreased the median number of any drinking days per month by 90% (0.7 vs 7.2; P = 0.005) and heavy drinking days per month by 93% (0.2 days vs 2.9 days; P = 0.007).

The XR-NTX 380 mg group also had more than twice as many responders compared with placebo (70% vs 30%; P = 0.006; responder defined as having no more than 2 heavy drinking days in any consecutive 28-day period) and experienced greater improvement in gamma-glutamyl transpeptidase levels (P = 0.03).

Outcomes for XR-NTX 190 mg (n = 26) were generally intermediate, demonstrating a dose-response effect.

In conclusion, XR-NTX 380 mg prolonged abstinence and reduced the number of heavy drinking days and drinking days in patients who were abstinent for as few as 4 days before treatment initiation.

Research report; O’Malley SS, Garbutt JC, Gastfriend DR, Dong Q, Kranzler HR. J Clin Psychopharmacol. 2007 Oct;27(5):507-12. Efficacy of extended-release naltrexone in alcohol-dependent patients who are abstinent before treatment.