Randomized controlled trial of dexamphetamine maintenance for the treatment of methamphetamine dependence.
OBJECTIVE
To investigate the safety and efficacy of once-daily supervised oral administration of sustained-release dexamphetamine in people dependent on methamphetamine.


METHODS
Randomized, double-blind, placebo-controlled trial.


METHODS
Forty-nine methamphetamine-dependent drug users from Drug and Alcohol Services South Australia (DASSA) clinics.


METHODS
Participants were assigned randomly to receive up to 110 mg/day sustained-release dexamphetamine (n = 23) or placebo (n = 26) for a maximum of 12 weeks, with gradual reduction of the study medication over an additional 4 weeks. Medication was taken daily under pharmacist supervision.


METHODS
Primary outcome measures included treatment retention, measures of methamphetamine consumption (self-report and hair analysis), degree of methamphetamine dependence and severity of methamphetamine withdrawal. Hair samples were analysed for methamphetamine using liquid chromatography-mass spectrometry.


RESULTS
Treatment retention was significantly different between groups, with those who received dexamphetamine remaining in treatment for an average of 86.3 days compared with 48.6 days for those receiving placebo (P = 0.014). There were significant reductions in self-reported methamphetamine use between baseline and follow-up within each group (P < 0.0001), with a trend to a greater reduction among the dexamphetamine group (P = 0.086). Based on hair analysis, there was a significant decrease in methamphetamine concentration for both groups (P < 0.0001). At follow-up, degree of methamphetamine dependence was significantly lower in the dexamphetamine group (P = 0.042). Dexamphetamine maintenance was not associated with serious adverse events.


CONCLUSIONS
The results of this preliminary study have demonstrated that a maintenance pharmacotherapy programme of daily sustained-release amphetamine dispensing under pharmacist supervision is both feasible and safe. The increased retention in the dexamphetamine group, together with the general decreases in methamphetamine use, degree of dependence and withdrawal symptom severity, provide preliminary evidence that this may be an efficacious treatment option for methamphetamine dependence.
Longo
Marie
M
Pharmacotherapies Research Unit, Drug and Alcohol Services South Australia, South Australia, Australia.
Wickes
Wendy
W
Smout
Matthew
M
Harrison
Sonia
S
Cahill
Sharon
S
White
Jason M
JM
D000293:Adolescent; D000328:Adult; D019969:Amphetamine-Related Disorders / Q000453:epidemiology / Q000534:rehabilitation* / Q000652:urine; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D015928:Cognitive Behavioral Therapy; D003692:Delayed-Action Preparations; D003913:Dextroamphetamine / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006197:Hair / Q000737:chemistry; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008694:Methamphetamine / Q000009:adverse effects* / Q000032:analysis; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data; D010352:Patient Dropouts / Q000706:statistics & numerical data; D012720:Severity of Illness Index; D013021:South Australia / Q000453:epidemiology; D015813:Substance Abuse Detection / Q000379:methods; D013375:Substance Withdrawal Syndrome / Q000453:epidemiology; D016896:Treatment Outcome; D055815:Young Adult
D000697:Central Nervous System Stimulants; D003692:Delayed-Action Preparations; D008694:Methamphetamine; D003913:Dextroamphetamine