Gabapentin, estrogen, and placebo for treating hot flushes: a randomized controlled trial

Abstract

Objective: To compare the efficacy of gabapentin, estrogen, and placebo in the treatment of hot flushes.

Methods: We performed a randomized, double-blind, placebo-controlled trial of 60 postmenopausal women to assess the efficacy of estrogen and gabapentin in the treatment of moderate-to-severe hot flushes. Participants were randomly assigned to receive either 0.625 mg/d of conjugated estrogens (n = 20), placebo (n = 20), or gabapentin titrated to 2,400 mg/d (n = 20) for 12 weeks. Participants recorded frequency and severity of baseline hot flushes on a hot flush diary for 2 weeks before randomization and for 12 weeks after randomization. The primary outcome measure was the weekly hot flush composite score, which takes into account both severity and frequency of hot flushes. Secondary outcome measures were differences in pre- and posttreatment scores pertaining to depression (Zung Depression Scale) and other climacteric symptoms (Greene Climacteric Scale).

Results: Intention-to-treat analysis showed that the reduction in the hot flush composite score for both estrogen (72%, P = .016) and gabapentin (71%, P = .004) was greater than the reduction associated with placebo (54%) at the conclusion of the 12th week. The extent of reduction in hot flush composite score, however, was not significantly different between estrogen and gabapentin (P = .63). No differences were seen between groups in the Zung Depression Scale, or in any of the Greene Climacteric subscales except for the Somatic Symptom cluster, which was significantly greater in the gabapentin arm than in the placebo arm. Despite a lack of group differences in adverse events, the Headache, Dizziness, and Disorientation cluster appeared with greater frequency in the gabapentin group. Estimation of the number needed to harm in this cluster suggests that these symptoms may occur with every fourth patient treated with gabapentin.

Conclusion: Despite the small scale of this study, gabapentin appears to be as effective as estrogen in the treatment of postmenopausal hot flushes.

Clinical trial registration: Clinicaltrials.gov, NCT 00276081.

Level of evidence: I.

Trial registration: ClinicalTrials.gov NCT00276081.