Finasteride-its impact on sexual function and prostate cancer

Area of Science:

• Dermatology and Urology
• Pharmacology

Background:

• Finasteride inhibits 5alpha-reductase type 2, reducing dihydrotestosterone (DHT), a key androgen in hair follicles and the prostate.
• Despite its FDA approval for androgenetic alopecia, patient and physician apprehension regarding sexual dysfunction often limits its use.

Purpose of the Study:

• To critically evaluate the evidence regarding finasteride's impact on sexual function and prostate cancer prevention.
• To address the concerns surrounding sexual adverse effects and their actual prevalence and significance.

Main Methods:

• Review of large-scale, long-term, placebo-controlled studies assessing erectile function using the International Index of Erectile Function-5 (IIEF-5) and Nocturnal Penile Tumescence (NPT).
• Analysis of semen parameters and prostate cancer incidence data from clinical trials.

Main Results:

• No clear evidence of negative effects on erectile function was found; reduction in ejaculatory volume is the only established sexual side effect.
• Semen parameters, excluding morphology, were reduced but remained within fertile limits.
• Finasteride significantly reduced low-grade prostate cancer incidence, though a paradoxical increase in high-grade cancer detection was noted, potentially due to improved PSA sensitivity.

Conclusions:

• Sexual adverse effects of finasteride are often overstated and should be considered alongside natural erectile dysfunction prevalence and potential nocebo effects.
• Finasteride is effective in reducing prostate cancer incidence, particularly low-grade forms, but requires careful interpretation regarding high-grade cancer detection.