Finasteride and Sexual dysfunction: is the FAERS signal real?
Finasteride ↔ Sexual dysfunction
Finasteride blocks the conversion of testosterone to the more potent dihydrotestosterone, and because it works by reducing androgen signalling it commonly causes sexual side effects — reduced libido, erectile dysfunction, and reduced ejaculate volume — that are a direct consequence of its pharmacology. Most cases reverse on stopping the drug, though a minority report persistent symptoms, a topic of continuing debate and labelling changes. The very high PRR (90.4) reflects both the real effect and the drug's wide use in prostate conditions and hair loss.
Regulatory basis: finasteride prescribing information (sexual adverse reactions; post-marketing persistent-effects reports).
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Sexual effects appear during treatment and usually resolve after withdrawal |
| Strength | met | PRR 90 — a very high relative signal on a large co-report count |
| Consistency | met | Reproduced in trials and post-marketing data |
| Specificity | met | A recognised finasteride effect, tied to its androgen mechanism |
| Biological gradient | partial | Dose-related |
| Plausibility | met | Reduced dihydrotestosterone signalling is the mechanism |
| Coherence | met | Coheres with the labelled sexual-side-effect warnings |
| Experiment | partial | A randomized trial recorded sexual side effects by arm; persistence is debated |
| Analogy | met | Analogous to sexual side effects from other anti-androgens and 5-alpha-reductase inhibitors |
This page's own qualitative read, not an automated/citation-gated assessment.