Riluzole for treatment of men with methamphetamine dependence: A randomized, double-blind, placebo-controlled clinical trial

Background: Riluzole is a glutamate regulator and effective in treatment of neuropsychiatric conditions. Aims: We assessed riluzole for treatment of methamphetamine dependence. Methods: In this randomized, double-blind, placebo-controlled clinical trial, male outpatients with methamphetamine dependence who were 18-65 years old received either 50 mg riluzole (n=34) or placebo (n=54) twice daily for 12 weeks. Patients were excluded in case of comorbid serious medical conditions or neurologic disorders, comorbid psychiatric disorders other than methamphetamine dependence requiring specific treatment interventions, simultaneous positive urine test result for substances of abuse other than methamphetamine, smoking >3 days per week, simultaneous consumption of medications which are contraindicated or have interaction with riluzole. Results: Concerning primary outcomes, the cumulative 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 the weekly measured rate of positive methamphetamine urine test results was significantly lower in the riluzole arm by the end of the study (riluzole=1 (5.00%), placebo=9 (45.00%), p-value=0.004). 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 two arms in terms of incidence of adverse events. Conclusion: Future randomized clinical trials are needed to investigate proper dosing strategy in a more inclusive sample.