Extended-Release Naltrexone Shows Rapid Onset : Pharmacokinetic data show that peak plasma concentration is reached on day 3 after injection.

In the patients with 4 days of abstinence, the median number of days to their first drink following treatment initiation was 12 days in the placebo group (28 subjects), 24 days for the low-dose group (26 subjects), and 42 days for the high-dose group (28 subjects).

In the patients with 7 days of abstinence, the median was 84 days for the high-dose group (17 subjects).

The groups with 4 and 7 days of abstinence who received the high dose both also reduced their median days of heavy drinking per month to 0.2 days.