Finasteride in Male Breast Cancer
August 2004
in “
Medisch-Farmaceutische Mededelingen
”
TLDR Long-term use of finasteride may cause breast cancer in men.
Finasteride, known as Proscar, was a medication used for benign prostatic hypertrophy (BPH) that worked by inhibiting the conversion of testosterone to the more potent dihydrotestosterone. Notable side effects included reduced libido, impotence, and gynecomastia. A concerning finding from the MTOPS study in 2003 indicated that long-term use of finasteride (average of 22 months) appeared to sporadically cause intraductal mammary carcinoma in men.