Finasteride Important Safety Information

Read this information carefully before starting finasteride. Discuss any questions with your provider. IMPORTANT: Women who are pregnant or may become pregnant must not take or handle crushed finasteride tablets.

What Is Finasteride?

Finasteride is a 5-alpha reductase inhibitor that blocks the conversion of testosterone to dihydrotestosterone (DHT). At 1mg daily (Propecia®), it is FDA-approved for the treatment of androgenetic alopecia (male pattern hair loss) in men. At 5mg (Proscar®), it is approved for benign prostatic hyperplasia. At Tactus Health, finasteride 1mg is prescribed for hair loss in men.

Contraindications

• Women: finasteride is not indicated for use in women
• Pregnant women must not take or handle crushed or broken finasteride tablets due to risk of absorption and potential fetal harm (specifically, ambiguous genitalia in male fetuses)
• Pediatric patients
• Known hypersensitivity to finasteride or any component

Warnings and Precautions

• Fetal Harm (Category X): Finasteride is absolutely contraindicated in pregnancy. Exposure of a pregnant woman to finasteride through handling crushed tablets or semen from a man taking finasteride may cause abnormalities of the external genitalia of a male fetus.
• Prostate Cancer Risk: Finasteride reduces PSA by approximately 50% in patients with benign prostatic hyperplasia. Adjust PSA interpretation accordingly. Finasteride does not increase the risk of high-grade prostate cancer but may affect detectability of low-grade disease.
• Post-Finasteride Syndrome: Some patients report persistent sexual side effects (low libido, erectile dysfunction, ejaculatory disorder) and mood changes that may persist after discontinuation. The causality and prevalence of persistent effects remains debated in the literature. Patients should discuss this risk with their provider before starting treatment.
• Breast Cancer: Rare cases of male breast cancer have been reported. Patients should promptly report any breast lumps, pain, nipple discharge, or other breast changes.

Adverse Reactions

Adverse reactions reported in Propecia® clinical trials at 1mg:

• Decreased libido (1.8%)
• Erectile dysfunction (1.3%)
• Ejaculatory disorder (1.2%)
• Decreased volume of ejaculate (0.8%)

Rates were low and comparable to placebo in clinical trials. Sexual side effects resolved upon discontinuation in most men. Some patients report persistent effects (see Post-Finasteride Syndrome above).

Blood Donation

Men taking finasteride should not donate blood until at least one month after the last dose due to the potential risk to a pregnant female recipient.

PSA Testing

Finasteride reduces serum PSA by approximately 50% in patients with androgenetic alopecia. If PSA testing is performed, this reduction must be factored into clinical interpretation. A rising PSA value on finasteride should be evaluated even if levels appear within normal range.