Important Safety Information — Finasteride

Indications

Finasteride is a 5-alpha-reductase inhibitor indicated for the treatment of male pattern hair loss (androgenetic alopecia) in men. It works by blocking the conversion of testosterone to dihydrotestosterone (DHT), the hormone primarily responsible for hair follicle miniaturization in genetically susceptible men.

Contraindications

• Women who are or may potentially be pregnant (may cause abnormalities of the external genitalia of a male fetus)
• Not indicated for use in women or pediatric patients
• Hypersensitivity to any component of the medication

Warnings and Precautions

• Exposure of women to finasteride: Women should not handle crushed or broken finasteride tablets, especially during pregnancy, due to the potential for absorption and risk to a male fetus. If a pregnant woman comes into contact with crushed tablets, wash the contact area immediately with soap and water.
• Effects on PSA and prostate cancer detection: Finasteride causes a decrease in serum PSA levels by approximately 50%. Any confirmed increase from the lowest PSA value while on finasteride may signal the presence of prostate cancer and should be evaluated, even if the value is within the normal range for untreated men.
• Sexual adverse reactions: Sexual side effects including decreased libido, erectile dysfunction, and ejaculation disorders (including decreased volume of ejaculate) have been reported. These reactions have been reported to persist in some patients after discontinuation of therapy.
• Mood and psychiatric effects: Depression, anxiety, suicidal ideation, and suicidal behavior have been reported in patients taking finasteride. If patients develop mood disturbances, consider discontinuing treatment.
• Breast changes: Breast tenderness and enlargement (gynecomastia) have been reported. Cases of male breast cancer have been reported, though a causal relationship has not been established.
• High-grade prostate cancer: An increased incidence of high-grade prostate cancer (Gleason score 7-10) was observed in men taking 5-alpha-reductase inhibitors in the PCPT and REDUCE trials.

Common Side Effects

• Decreased libido (reported in 1.8% of patients in clinical trials)
• Erectile dysfunction (reported in 1.3% of patients in clinical trials)
• Ejaculation disorder, including decreased volume of ejaculate (reported in 1.2% of patients in clinical trials)

Serious Side Effects

Seek medical attention if you experience any of the following:

• Persistent sexual dysfunction (decreased libido, erectile dysfunction, ejaculation disorders) that continues after discontinuation
• Depression, anxiety, or suicidal thoughts
• Breast lumps, pain, nipple discharge, or other breast changes
• Signs of allergic reaction: rash, itching, hives, swelling of the lips, tongue, throat, or face
• Testicular pain
• Cognitive changes (difficulty concentrating, brain fog)

Drug Interactions

No clinically significant drug interactions have been identified with finasteride. Finasteride does not appear to affect the cytochrome P450-linked drug-metabolizing enzyme system. However, inform your healthcare provider of all medications you are currently taking, including:

• Other 5-alpha-reductase inhibitors (e.g., dutasteride)
• Testosterone or other androgen therapies
• Over-the-counter supplements and herbal products

Use in Specific Populations

• Pregnancy: Contraindicated. Category X. Known to cause birth defects in male fetuses.
• Women: Not indicated for use in women.
• Pediatric use: Not indicated for use in pediatric patients.
• Geriatric use: No dosage adjustment is necessary for elderly patients, though efficacy for hair loss in elderly patients has not been established.
• Hepatic impairment: Use with caution in patients with liver function abnormalities, as finasteride is metabolized extensively in the liver.
• Blood donation: Patients taking finasteride should not donate blood until at least one month after their last dose to prevent administration of finasteride to a pregnant female transfusion recipient.