Placing transdermal selegiline for major depressive disorder into clinical context: number needed to treat, number needed to harm, and likelihood to be helped or harmed

Abstract

Background: This is a quantitative review of existing studies of transdermal selegiline for major depressive disorder.

Methods: Data for dichotomous outcomes were extracted from the five 6-8 week studies of transdermal selegiline. Number needed to treat (NNT) vs. placebo was calculated for response and remission using standard definitions. Number needed to harm (NNH) vs. placebo for commonly encountered adverse events (AEs), AEs associated with sexual function, incidence of weight gain ≥5% from baseline, and discontinuation due to an AE, were also calculated. Data was pooled as appropriate and likelihood to be helped or harmed (LHH) ratios contrasting remission with selected tolerability outcomes were determined.

Results: When pooling together the two pivotal trials as identified in product labeling, NNT for response was 11 (95% CI 6-109) and for remission, 9 (95% CI 6-28). Pooling all trials, NNH for application site reaction was 7 (95% CI 6-10) and for insomnia, 19 (95% CI 12-41). There were no clinically relevant differences from placebo regarding weight gain or impairment in sexual functioning. NNH for discontinuation due to an AE was 32 (95% CI 19-132). LHH for remission vs. discontinuation from treatment due to an AE was 3.6.

Limitations: The studies included were not identical in design. The studies were registrational in nature and thus not necessarily generalizable.

Conclusions: NNT for transdermal selegiline for efficacy is similar to that for other antidepressant regimens for which similar analyses have been published. There appear to be no clinically relevant effects of selegiline on weight or sexual functioning.

Keywords: Evidence-based medicine; Major depressive disorder; Number needed to harm; Number needed to treat; Selegiline; Transdermal.