No Evidence of Post-Finasteride Syndrome in 267,983 person-years follow-up in the Prostate Cancer Prevention Trial

To investigate Post-Finasteride Syndrome, a broad range of symptoms reported in case reports and case series among patients who have received finasteride, a five-alpha reductase inhibitor. We evaluate the frequency of these symptoms in the Prostate Cancer Prevention Trial (PCPT), a large-scale randomized, placebo-controlled trial of finasteride.

Records of subjects enrolled in the PCPT were linked to Medicare claims data. Medicare claims were queried for a group of 22 conditions potentially attributed to PFS, including sexual and cognitive symptoms. Logistic regression and Cox regression analyses, comparing former finasteride use to matched placebo, were adjusted for age, race, BMI, and family history of prostate cancer.

Of 18,880 eligible subjects, 15,122 were linked to Medicare; of these 14,239 had one or more years of continuous coverage. Median follow-up from study registration to end of Medicare enrollment was 20 years with 267,983 person-years of follow-up. Of the 22 conditions potentially related to PFS, none had a statistically significant association with treatment arm.

In the largest placebo-controlled study of the five-alpha reductase inhibitor, finasteride, long-term follow-up does not support the concept of a 'Post-Finasteride Syndrome'. The anecdotal reports to date are likely related to the ubiquitous nature of these symptoms in an aging population and reporting bias.