Proscar

Proscar is a brand name for finasteride, a prescription medication in the 5-alpha-reductase inhibitor class. It is used mainly to treat symptoms of benign prostatic hyperplasia (BPH), a noncancerous enlargement of the prostate gland that can affect urination. Proscar reduces the size of the prostate and can improve urinary flow and reduce the risk of acute urinary retention in some men.

Mechanism of action: Finasteride inhibits the enzyme 5-alpha-reductase type II, which converts testosterone into dihydrotestosterone (DHT). Lower DHT levels in the prostate lead to decreased prostatic growth and a reduction in prostate volume over time. Because finasteride also lowers DHT levels in other tissues, it can affect sex hormone–related functions.

Administration and dosage: Proscar is supplied as a 5 mg oral tablet and is typically taken once daily, with or without food. Improvement in BPH symptoms may take several months. The medication can affect PSA test results, reducing PSA levels by about 50%, which can influence prostate cancer screening interpretation.

Side effects and risks: Common adverse effects include decreased libido, erectile dysfunction, and ejaculation disorders. Other possible effects are breast tenderness or enlargement, rash, and mood changes. Serious side effects are rare but can include allergic reactions. Women who are or may become pregnant should avoid handling broken or crushed Proscar tablets due to potential risks to a male fetus.

Contraindications and interactions: Finasteride is contraindicated in men with hypersensitivity to the drug and should be used with caution in those with liver disease. Discuss all medications with a healthcare provider to assess potential interactions.

Relationship to other formulations: Propecia, a 1 mg formulation of finasteride, is used for male pattern hair loss, while Proscar’s 5 mg dose is approved for BPH. Proscar received FDA approval for BPH in 1992; generic finasteride is now widely available.