FINASTERIDE (PROPECIA) is generally well tolerated. Side effects, which usually have been mild, generally have not required discontinuation of therapy.
Finasteride for male pattern hair loss has been evaluated for safety in clinical studies involving more than 3,200 men. In three 12-month, placebo-controlled, double-blind, multicenter studies of comparable design, the overall safety profiles of FINASTERIDE (PROPECIA) and placebo were similar. Discontinuation of therapy due to any clinical adverse experience occurred in 1.7% of 945 men treated with FINASTERIDE (PROPECIA) and 2.1% of 934 men treated with placebo.
In these studies, the following drug-related adverse experiences were reported in ≥1% of men treated with FINASTERIDE (PROPECIA): decreased libido [FINASTERIDE (PROPECIA), 1.8% vs. placebo, 1.3%] and erectile dysfunction (1.3%, 0.7%). In addition, decreased volume of ejaculate was reported in 0.8% of men treated with FINASTERIDE (PROPECIA) and 0.4% of men treated with placebo. Resolution of these side effects occurred in men who discontinued therapy with FINASTERIDE (PROPECIA) and in many who continued therapy. In a separate study, the effect of FINASTERIDE (PROPECIA) on ejaculate volume was measured and was not different from that seen with placebo.
The incidence of each of the above side effects decreased to ≤0.3% by the fifth year of treatment with FINASTERIDE (PROPECIA).
Finasteride has also been studied in men with prostate disease at 5 times the dosage recommended for the treatment of male pattern hair loss. During the 4- to 6-year placebo- and comparator-controlled Medical Therapy of Prostatic Symptoms (MTOPS) study that enrolled 3047 men, there were 4 cases of breast cancer in men treated with finasteride 5 mg but no cases in men not treated with finasteride 5 mg. During the 4-year, placebo-controlled PLESS study that enrolled 3040 men, there were 2 cases of breast cancer in placebo-treated men but no cases in men treated with finasteride 5 mg. During the 7-year placebo-controlled Prostate Cancer Prevention Trial (PCPT) that enrolled 18,882 men, there was 1 case of breast cancer in men treated with finasteride 5 mg, and 1 case of breast cancer in men treated with placebo. There have been postmarketing reports of male breast cancer with the use of finasteride 1 mg and 5 mg. The relationship between long-term use of finasteride and male breast neoplasia is currently unknown.
The following additional adverse experiences have been reported in postmarketing use. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate the frequency or establish a causal relationship to drug exposure.
Immune system disorders:
hypersensitivity reactions such as rash, pruritus, urticaria, and angioedema (including swelling of the lips, tongue, throat and face).
depression; decreased libido that continued after discontinuation of treatment.
Reproductive system and breast disorders:
sexual dysfunction (erectile dysfunction and ejaculation disorders) that continued after discontinuation of treatment; breast tenderness and enlargement; testicular pain; hematospermia; male infertility and/or poor seminal quality. Normalization or improvement of seminal quality has been reported after discontinuation of finasteride.