Context

Finasteride, a 5α-reductase inhibitor used in benign prostatic hyperplasia and androgenetic alopecia, has been associated with an increased suicidal risk, whereas it is unclear whether such risk is similar to that for another 5α-reductase inhibitor, dutasteride.

Objective and method

We aimed to assess the risk of suicidal behaviours with finasteride relative to dutasteride. A nationwide cohort study was conducted using the French National Health Data System (SNDS). Men aged 50 years or older initiating finasteride 5 mg or dutasteride 0.5 mg in France between 01-01-2012 and 30-06-2016 were included and followed until outcome (suicide death identified from death certificate or self-harm hospitalisation), treatment discontinuation or switch, death, or 31-12-2016. Self-harm by violent means or resulting in admission to an intensive care unit were also examined. Cox proportional hazards models controlled for age and psychiatric and non-psychiatric conditions by inverse probability of treatment weighting (IPTW). Analyses were stratified according to psychiatric history. The study compared 69,786 finasteride new users to 217,577 dutasteride new users (median age: 72.0 years [Q1–Q3 = 64.5–80.2] vs. 71.1 [Q1–Q3 = 65.0–79.2]).

Results

During follow-up, 18 suicide deaths (0.57/1000 person-years) and 34 self-harm hospitalisations (1.08/1000) occurred among finasteride users versus 47 deaths (0.43/1000) and 87 hospitalisations (0.79/1000) among dutasteride users. Overall, finasteride was not associated with an increased risk of any suicidal outcome (IPTW-adjusted Hazard Ratio = 1.21 [95% Confidence Interval  .87–1.67]), suicide death or self-harm hospitalisation. However, among individuals with a history of mood disorders, finasteride was associated with an increased risk of any suicidal outcome (25 versus 46 events; HR = 1.64 [95% CI 1.00–2.68]), suicide death (8 versus 10 events; HR = 2.71 [95% CI 1.07–6.91]), self-harm by violent means (6 versus 6 events; HR = 3.11 [95% CI 1.01–9.61]), and self-harm with admission to an intensive care unit (7 versus 5 events; HR = 3.97 [95% CI 1.26–12.5]). None of these risks was significantly increased among individuals without a psychiatric history.

Conclusion

These findings do not support an increased risk of suicide with finasteride used in the treatment of benign prostatic hyperplasia. However, an increased risk cannot be excluded among men with a history of mood disorder, but this result based on a limited number of events should be interpreted with caution.