Abstract
Naltrexone has been tested in numerous clinical trials for both safety and efficacy in the treatment of relapse to opioid dependence. In the doses used for this purpose, it has been found to be safe and pharmacologically effective. Recently it has been found that chronic treatment with naloxone or naltrexone produces supersensitivity to opioid agonists in rodents. Seven normal human volunteers were tested for opiate sensitivity, using morphine 8 mg iv before and after 2 weeks of naltrexone treatment at 50 mgpo qd. There were no significant differences in morphine-induced respiratory depression before or after naltrexone treatment. These results indicate that at the dose of morphine used in this study, it is unlikely that naltrexone maintenance would increase the risk of opiate toxicity.