Oral finasteride use and sexual adverse events: signal detection from disproportionality analyses of data from the United States Food and Drug Administration Adverse Event Reporting System.

BACKGROUND

Oral finasteride 1 milligram (1 mg) daily-which is a 5-alpha reductase inhibitor (5-ARI) approved by the Food and Drug Administration (FDA) for androgenetic alopecia-is linked to sexual adverse events (AEs). However, it remains unclear whether this link is causal or merely correlational.

METHODS

In FAERS, AEs are described by preferred terms (pts) of the Medical Dictionary for Regulatory Activities system; we investigated 8 AEs, including erectile dysfunction (pt = 10,061,461). We determined if signals could be detected with finasteride 1 mg-and 0.5 mg of dutasteride (a more potent 5-ARI)-in FAERS, for sexual AEs related to the post-finasteride syndrome (PFS): for the two, we identified the yearly number of cases (i.e. reports with sexual AEs) from 2006 to 2024. For each AE, we conducted a disproportionality analysis where reporting odds ratios (RORs) were estimated-along with p-values and 95% confidence intervals (CIs).

RESULTS

There were more reports with finasteride 1 mg than with dutasteride 0.5 mg; for both, more reporting was observed as of 2012, the year the PFS foundation formally propagated PFS awareness.

CONCLUSIONS

Our findings support that the disproportionately higher reporting of sexual AEs with finasteride 1 mg than with dutasteride 0.5 mg-even more so after 2012-could be attributed to the nocebo effect.