Double-blind placebo-controlled evaluation of the PROMETA™ protocol for methamphetamine dependence.

AIMS: To evaluate the efficacy and safety of the PROMETA™ Protocol for treating methamphetamine dependence. DESIGN: A double-blind, placebo-controlled 108-day study with random assignment to one of two study conditions: active medication with flumazenil (2 mg infusions on days 1, 2, 3, 22, 23), gabapentin (1200 mg to day 40) and hydroxazine (50 mg to day 10) versus placebo medication (with active hydroxazine only). SETTING: Three substance abuse treatment clinics: two in-patient, one out-patient. PARTICIPANTS: Treatment-seeking, methamphetamine-dependent adults (n = 120). MEASUREMENTS: Primary outcome was percentage of urine samples testing negative for methamphetamine during the trial. FINDINGS: No statistically significant between-group differences were detected in urine drug test results, craving, treatment retention or adverse events. CONCLUSIONS: The PROMETA protocol, consisting of flumazenil, gabapentin and hydroxyzine, appears to be no more effective than placebo in reducing methamphetamine use, retaining patients in treatment or reducing methamphetamine craving.

Pharmacokinetics of buprenorphine: a comparison of sublingual tablet versus liquid after chronic dosing.

Although buprenorphine is approved for use in the outpatient treatment of opioid addiction in 2 tablet formulations, a monoproduct containing buprenorphine only (Subutex) and a buprenorphine/naloxone combination product (Suboxone), much of the clinical data that support the approval by the U.S. Food and Drug Administration were generated by using a sublingual liquid. To interpret the literature in prescribing parameters for tablet buprenorphine, this study was designed to determine steady state buprenorphine plasma levels for the 2 formulations and to assess the relative bioavailability of each. A randomized, double-blind, crossover study with dose increases was conducted during a 12-week period at an outpatient treatment clinic. Of the 184 subjects initially randomized to treatment, 133 (72.3%) were evaluated for the steady-state trough plasma concentration, 16 (8.7%) for relative bioavailability, and 31 (16.8%) for dose proportionality. At steady state, differences in the trough plasma concentrations of buprenorphine between the 2 formulations were found across all the dose levels. Average plasma concentration (Cavg) of the tablet at twice the milligram dose of the liquid was twice that of the liquid; intersubject variability was greater for the tablet. At double the dose of tablet, there is no difference in steady state plasma concentrations. The bioavailability seems equivalent for the 2 formulations across all the dose levels.

A screening trial of amantadine as a medication for cocaine dependence.

This screening trial evaluated whether amantadine hydrochloride (100 mg bid) demonstrated sufficient clinical efficacy compared to placebo to recommend development as a pharmacotherapy for cocaine dependence. Participants were randomized to amantadine (n=34) or placebo (n=35) conditions in a 16-week, placebo-controlled, double blind trial with three times per week group counseling. Amantadine-treated participants were retained significantly longer than placebo. Based on results of a joint probability index for urine drug testing results (i.e. the proportion of cocaine-metabolite free urine samples divided by the number of participants assigned to the condition), participants assigned to amantadine were found to be significantly more likely to be cocaine abstinent on the last day of 8-weeks of treatment than participants assigned to placebo. Results at the end of 16 weeks of treatment were similar. Standard measures of urine drug testing consistently favored the amantadine condition over placebo, although not at levels of statistical significance. There was no statistical significance infrequency or severity of reported adverse events by treatment condition. Participants assigned to amantadine exhibited greater reductions in global staff ratings of cocaine dependence severity from baseline to termination compared with placebo. There were no significant differences in frequency or severity of reported adverse events by treatment condition. These results provide moderate support for further study of amantadine for the treatment of cocaine dependence.