Comparative efficacy of nonhormonal drugs on menopausal hot flashes

The effects of nonhormonal drugs on menopausal hot flashes are still not well quantified. We therefore did a model-based meta-analysis (MBMA) to quantitate and compare the efficacy features of nonhormonal drugs on menopausal hot flashes. Literature was searched in the public databases to extract data of clinical trials on nonhormonal drugs, including selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs), gabapentin, clonidine, and soy isoflavones. Pharmacodynamic models were used for the quantitative analysis of each drug. Thirty-nine studies were included in the analysis. The results revealed a classic pharmacodynamic maximal effect (E-max) model could describe the time course of hot-flash reduction by nonhormonal drugs. After deducting placebo effects, the E-max of SSRIs/SNRIs, gabapentin, clonidine, and soy isoflavones was 13.9 %, 14.8 %, 18.5 %, and 25.0 %, respectively. The time to achieve half of the maximal effect (ET50) of SSRIs/SNRIs, gabapentin, clonidine, and soy isoflavones was 0.18 weeks, 0 weeks, 0 weeks, and 11.6 weeks, respectively. The results showed that SSRIs/SNRIs, gabapentin, and clonidine had a rapid onset, which could reach the maximum effect immediately. However, the onset of soy isoflavones was very slow, and a duration of 16.6 weeks was needed to surpass the efficacy of paroxetine (a type of SSRIs). The information provided in this study can be used as valuable supplementary information for treatment guidelines of nonhormonal drugs on menopausal hot flashes.