Finasteride and Male Infertility: A Case for Prospective Collaborative Research Databases

The University of Toronto conducted a study on 27 men who had been taking 1 mg of finasteride for approximately 5 years and found an 11.6-fold increase in sperm counts 2 to 3 months after finasteride discontinuation, with 57% of men with severe oligozoospermia (<5 million/mL) having counts increase to >15 million/mL. The authors found no impact of finasteride on motility, morphology, or hormone parameters in this group of men. Finasteride at 5 mg daily was approved by the U.S. Food and Drug Administration (FDA) in 1992 for benign prostatic hyperplasia. At 1 mg daily finasteride was approved in 1997 for androgenic alopecia (Propecia; Merck) and is used by many men of reproductive age. The study highlights the importance of large, collaborative, prospectively designed databases to study rare conditions such as male factor infertility, where claims-based analyses are not feasible.