RILUZOLE FOR TREATMENT OF MEN WITH METHAMPHETAMINE DEPENDENCE: A RANDOMIZED, DOUBLE-BLIND, PLACEBO-CONTROLLED CLINICAL TRIAL

Background and Aim : Dependence on illicit drugs, in particular those in the category of stimulants, is a worldwide growing health concern. Methamphetamine is a highly addictive psychostimulant. Currently, there is no well-established treatment for methamphetamine dependence and a variety of interventions are subject to research. Riluzole seems a promising candidate to be studied in treatment of methamphetamine dependence for the first time. Methods : This was a 12-week, randomized, double-blind, placebo-controlled, parallel-group clinical trial of Riluzole in patients with methamphetamine dependence. Based on randomization, participants received either 50 mg Riluzole or placebo twice daily for 12 weeks. Primary outcomes were defined as mean difference in the number of weekly visits attended by the patients during the trial and difference in distribution of positive urine test results for methamphetamine at week 12 between the two treatment arms. Secondary outcomes included mean differences in score change from baseline to week 12 for Amphetamine Selective Severity Assessment, Amphetamine Withdrawal Questionnaire, Stimulant Craving Questionnaire, Visual Analogue Scale for Craving, and Hamilton Depression Rating Scale. Time treatment interaction effect was also calculated using all 13 weekly measurements for each scale except for HAM-D which was measured in 7 visits. Difference in distribution of adverse events between the two treatment arms was another important secondary outcome in this study.Results : Concerning primary outcomes, mean number of attended weekly visits was higher in the riluzole arm compared with the placebo arm approaching a statistically significant difference (riluzole, median (range)= 13.00 (2.00-13.00); placebo= 4.00 (2.00-13.00); Mann-Whitney U= 505.00, p-value= 0.073), and rate of positive methamphetamine urine test results were significantly lower in the riluzole arm by the end of the study at week 12 (riluzole= 1(5.00%), placebo= 9(45.00%), p-value= 0.004). Furthermore, patients in the riluzole arm experienced significantly greater improvement on all the craving, withdrawal, and depression measures regarding mean score changes from baseline to endpoint. No significant difference was detected between the riluzole and placebo arms in terms of incidence of adverse events.Conclusion : The promising results of this study warrant future randomized clinical trials to investigate proper dosing strategy for riluzole in a more inclusive sample of patients with methamphetamine/amphetamine dependence, while simultaneously investigating possible biological mechanisms of action

Keywords:

Clinical trial , Methamphetamine , Riluzole , Substance abuse