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Research Summary

Injectable Risperidone for the Treatment of Methamphetamine Dependence

Methamphetamine (MA) abuse affects 25 million people in the United States. No pharmacologic options currently exist to treat MA abuse, and behavioral interventions tend to have high rates of relapse. This open label trial sought to determine the effectiveness of long-acting injectable risperidone on MA use in patients meeting criteria for MA dependence (N=34). Those subjects who tolerated an initial 7-day trial of oral risperidone (n=22) were then started on injectable risperidone (25 mg every other week for 8 weeks). Subjects were assessed weekly during the trial and at 12 weeks after study completion. Each received at least 1 injection. The majority of participants were male (86%) and white (86%). Mean period of methamphetamine use among subjects was 12.2 years (± 8.6 years).

 

  • Mean MA use per week decreased from 4.1 to 1.0 days (p<0.001). No adverse events were reported.
  • In the subgroup of patients in whom craving was assessed (n=15), visual analog scale of craving measures decreased significantly between baseline and study completion.
  • Verbal memory scores improved at week 4, but the improvement was not maintained at week 8. No other differences in neurocognitive test scores were found.

Comments:

Although methamphetamine use decreased in participants who received injectable risperidone, this study is limited by its small sample size, high rate of attrition, and open label design. Roughly 25 percent of patients did not tolerate oral risperidone and thus did not receive the injectable form, and only 17% of patients completed the 12-week follow-up. As such, these results should be interpreted with caution. Jeanette M. Tetrault, MD

Reference:

Meredith CW, Jaffe C, Cherrier M, et al. Open Trial of Injectable Risperidone for Methamphetamine Dependence. J Addict Med. 2009;3(2):55–65.

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