Determination of naltrexone dosage for narcotic agonist blockade in detoxified Asian addicts

Thirty-eight, adult, male, detoxified, Malaysian opiate addicts participated in this double-blind clinical evaluation of naltrexone. Addicts from three ethnic groups: Chinese, Malays, and Indians received a weekly regimen of naltrexone (100 mg on Days 1 and 3, and 150 mg on Day 5). Subjects were randomly assigned to receive intravenous challenge with either 25 mg heroin or placebo 12, 24, 48, and 72 h after the third naltrexone dose. Physiological and subjective parameters were measured at each challenge interval. Results indicated that naltrexone was effective in blocking the physiological and psychological effects of heroin for at least 48 and 72 h, respectively, in detoxified Malaysian opiate addicts. The efficacy of naltrexone did not differ among the three ethnic groups evaluated in this study.