Naltrexone could be a promising adjunct pharmacologic treatment for methamphetamine addiction, as it significantly reduced cue-induced cravings and subjective responses to methamphetamine in this first-of-its-kind study to be conducted in the United States.
Lara Ray, PhD, from the University of California, Los Angeles, and colleagues designed a doubled-blind, randomized, crossover, placebo-controlled study of 30 non-treatment-seeking individuals meeting DSM-IV criteria for methamphetamine abuse or dependence (average methamphetamine use of 3–4 days per week). Patients completed two separate inpatient stays lasting five days, during which testing sessions of methamphetamine cue-reactivity and intravenous methamphetamine administration (30mg) after receiving oral naltrexone (25mg on Days 1 and 2, 50mg on Days 3 and 4) or placebo for four days. Ten days later, the patients were readmitted and the intervention and control groups were switched. The primary outcomes were cue-induced cravings and subjective responses to methamphetamine administration.
Naltrexone decreased overall subjective ratings of “crave drug,” “stimulated,” and “would like drug access,” decreased the post-methamphetamine administration time course of “anxious,” and increased ratings of “bad drug effects” vs. placebo. The effects of naltrexone were slightly reduced for men compared to women but the effects on those receiving the drug were similar among those receiving it in the first and second inpatient stays.
Naltrexone, an opioid antagonist, is currently approved as adjunct in the treatment of alcohol or narcotic dependence. A clinical trial sponsored by the National Institute on Drug Abuse is currently underway.
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