Many patients with alcohol dependence do not receive the full benefits of treatment because they do not adhere to it. In part to address issues with adherence, extended-release (ER) naltrexone, which is released over a month after one injection, was developed. Researchers assessed ER-naltrexone efficacy in a subgroup of 82 subjects in a larger clinical trial who had ≥4 days of abstinence.

In that subgroup, 380 mg of ER-naltrexone in 28 subjects versus placebo in 28 subjects

• increased the time to first drink (median days, 41 versus 12);
• increased continuous abstinence over 6 months (32% versus 11%);
• increased time to first heavy drinking (>180 versus 20 days);
• decreased days with any drinking (median days per month, 0.7 versus 7.2);
• decreased days with heavy drinking (median days per month, 0.2 versus 2.9).

Smaller benefits, which were not always statistically significant, were found among 28 subjects treated with 190 mg of ER-naltrexone.

Comments by Michael Levy, PhD:
In this industry-sponsored secondary analysis of a small subgroup of subjects who had achieved just 4 or more days of abstinence before entering treatment, those who received ER-naltrexone in conjunction with psychosocial treatment had better treatment outcomes than those who received placebo. Medications with proven benefit for the treatment of alcohol dependence tend to be underutilized in general. This study suggests that ER-naltrexone is another treatment option for clients with alcohol dependence who have achieved even a short duration of abstinence.