Pilot trial of gabapentin for the treatment of benzodiazepine abuse or dependence in methadone maintenance patients

Abstract

Background: Benzodiazepine use disorders are a common clinical problem among methadone maintenance treatment patients and have adverse effects on clinical outcomes.

Objectives: To evaluate gabapentin for the outpatient treatment of benzodiazepine abuse or dependence in methadone maintenance patients.

Methods: Participants (n = 19) using benzodiazepines at least 4 days per week were enrolled into an 8-week randomized double-blind placebo-controlled outpatient pilot trial. All participants received a manual-guided supportive psychotherapy aimed to promote abstinence. Study medication was titrated over a 2-week period to a maximum dose of gabapentin 1200 mg or placebo three times a day. Benzodiazepine use was assessed using urine toxicology confirmed self-report. Benzodiazepines were not provided as part of study participation; participants were provided guidance to gradually reduce benzodiazepine intake.

Results: Sixteen participants had post-randomization data for analysis. Retention at week eight was 50%. The mean dose of gabapentin achieved by titration was 2666 mg/day (SD = ± 1446). There were no significant between group differences on benzodiazepine use outcomes (amount benzodiazepine per day [Mann-Whitney U = 27, p = 0.745], abstinent days per week [U = 28, p = 0.811]) and Clinical Instrument Withdrawal Assessment (CIWA)-benzodiazepines scale (U = 29.0, p = 0.913). One participant in the gabapentin group discontinued study medication because of peripheral edema. Two participants in the placebo group requested admission for inpatient detoxification treatment.

Conclusion: In outpatient methadone-maintained patients with benzodiazepine use disorder, gabapentin did significantly decrease benzodiazepine use relative to placebo. The small sample recruited for this trial may have limited the ability to detect a group difference.

Trial registration: ClinicalTrials.gov NCT00420771.

Keywords: Benzodiazepines; gabapentin; methadone treatment.

Figures

Figure 1

Participants’ progress through the screening, entry, randomization and medication phases of the treatment trial

Figure 2

Median Change in Benzodiazepine Use (Equivalent Lorazepam mg Per Day). Comparison of the experimental and placebo groups in the mean amount of benzodiazepine used per day calculated over the week prior to study entry (baseline) and the last week of study participation (end of study).