Randomized, placebo-controlled pilot trial of gabapentin during an outpatient, buprenorphine-assisted detoxification procedure

Abstract

This pilot study examined the efficacy of the N-type calcium channel blocker gabapentin to improve outcomes during a brief detoxification protocol with buprenorphine. Treatment-seeking opioid-dependent individuals were enrolled in a 5-week, double-blind, placebo-controlled trial examining the effects of gabapentin during a 10-day outpatient detoxification from buprenorphine. Participants were inducted onto buprenorphine sublingual tablets during Week 1, were randomized and inducted onto gabapentin or placebo during Week 2, underwent a 10-day buprenorphine taper during Weeks 3 and 4, and then were tapered off gabapentin/placebo during Week 5. Assessments included thrice-weekly opioid withdrawal scales, vitals, and urine drug screens. Twenty-four individuals (13 male; 17 Caucasian, 3 African American, 4 Latino; mean age 29.7 years) participated in the detoxification portion of the study (gabapentin, n = 11; placebo, n = 13). Baseline characteristics did not differ significantly between groups. Self-reported and observer-rated opioid withdrawal ratings were relatively low and did not differ between groups during the buprenorphine taper. Urine results showed a Drug × Time interaction, such that the probability of opioid-positive urines significantly decreased over time in the gabapentin versus placebo groups during Weeks 3 and 4 (OR = 0.73, p = .004). These results suggest that gabapentin reduces opioid use during a 10-day buprenorphine detoxification procedure.

Figure 1

Flow diagram of subject progress through the phases of the randomized clinical trial. BUP refers to buprenorphine and GBP refers to gabapentin. The * indicates that one participant who did not complete the induction protocol underwent the buprenorphine taper. The ** indicates that a participant who completed the buprenorphine taper dropped out of the study prior to the gabapentin taper.

Figure 2

Percentage of participants retained in each of the two treatment groups during each week of the study. X-axis: visit and phase of study.

Figure 3

Scores on the Opioid Withdrawal Symptom Checklist (left panel) and the Objective Opioid Withdrawal Scale (right panel). X-axis: number of visit and phase of study. Each data point represents the mean ± S.E.

Figure 4

Percentage of participants with urine drug screens positive for opioids/opiates at each time point during the BUP taper (weeks 3–4) and the gabapentin taper (week 5). X-axis: visit and phase of study.