Short-term effects of naltrexone in 155 heroin ex-addicts.

The narcotic antagonist naltrexone was administered for periods of up to 8 months to a total of 155 patients at a dose of 40-200 mg per day. The antagonistic effect of naltrexone was tested by injections of heroin. Eighty milligrams of natrexone was effective for 48hr. The antagonistic effect decreased at 72 hr after the administration of 120-200 mg of naltrexone. Laboratory tests indicated no signs of toxicity. Naltrexone may elicit an increase in blood pressure and opigastric pain. Neither of these side effects appear clinically important. No signs of dependence on naltrexone were detected. These results suggest that naltrexone may be useful for clinical treatment of opiate dependence.