Medically reviewed by Dr. Kimberly Langdon Cull, M.D. on Oct. 4, 2023
This meta-analysis demonstrated that the majority of individuals taking paroxetine experienced a reduction in vasomotor symptoms (hot flashes); however, the same effect could be achieved by an inert placebo. The maximum true effect of paroxetine is estimated to be 32%.
Vasomotor symptoms, including hot flashes, are frequent complaints among menopausal and post-menopausal women. The US Food and Drug Administration (FDA) has approved paroxetine mesylate as the only non-hormonal therapeutic approach; however, there is limited evidence pertaining to the drug’s efficacy, benefits, and magnitude of placebo response.
This meta-analysis aimed to analyze the magnitude of the placebo response in clinical trials of paroxetine to treat vasomotor symptoms. The study’s findings are published in the journal Frontiers in Psychiatry.
Characteristics of Included Studies
The meta-analysis included six randomized controlled trials (RCTs), comprising 1486 menopausal and post-menopausal women. The study population also included women who were experiencing vasomotor symptoms but whose menopausal status was not specified. The age range of the study participants was 36–76 years. The most frequent ethnicity was Caucasian/White, followed by African American/Black. The risk of bias in the included RCTs did not significantly affect the study and analysis findings.
Percentage Reduction in the Vasomotor Symptoms
The average percentage reduction in vasomotor symptoms was 51% and 39% with paroxetine and placebo, respectively. Hence, paroxetine reduced hot flashes by, on average, an additional 12%.
Paroxetine Effect Size for Vasomotor Symptoms
The mean effect size in the paroxetine and placebo groups for hot flash frequency was 1.35 SDs and 1.07 SDs, respectively. The mean unique treatment effect size for paroxetine was 0.28 SDs. Approximately 79.26% of the treatment response to paroxetine is attributable to the placebo response, yielding a mean true drug effect of approximately 20.74%. The mean effect size for hot flash severity in the paroxetine and placebo groups was calculated to be 0.41 SDs and 0.28 SDs. The mean unique treatment effect size was estimated to be 0.13 SDs. Approximately 68.29% of treatment responses for hot flash severity are attributed to the placebo response. This yields a mean true drug effect of approximately 31.71%.
Source:
Rhodes, J. R. (2023). Magnitude of placebo response in clinical trials of paroxetine for vasomotor symptoms: a meta-analysis. Frontiers in Psychiatry, 14. https://doi.org/10.3389/fpsyt.2023.1204163
