Dutasterid

Dutasterid, commonly written dutasteride, is a prescription medication that acts as a dual inhibitor of the 5-alpha-reductase enzymes type I and II, reducing the conversion of testosterone to dihydrotestosterone (DHT). By lowering DHT levels, it can affect conditions driven by this androgen.

It is approved for the treatment of benign prostatic hyperplasia (BPH) to improve symptoms and reduce the risk of acute urinary retention and the need for surgery. It is typically taken as a 0.5 mg oral tablet and is sometimes prescribed in combination with an alpha-1 blocker such as tamsulosin (in some markets sold as a fixed-dose combination under brand names like Jalyn). In certain countries, dutasteride is also approved for the treatment of androgenetic alopecia (male pattern hair loss), though this use is not universal and may be off-label in some jurisdictions. It is not approved for use in women.

Pharmacology and dosing: Dutasteride has a long elimination half-life, with steady-state levels reached after several weeks of daily use. It suppresses circulating DHT by about 90%, though tissue responses can vary. The usual dose for BPH is 0.5 mg once daily; dosing for hair loss, when used, is typically the same, but indications may differ by country.

Adverse effects and safety: Potential sexual side effects include decreased libido, erectile dysfunction, and ejaculation disorders. Gynecomastia and breast tenderness can occur. Rare liver effects and hypersensitivity reactions have been reported. Pregnant women or those who may become pregnant should avoid handling the tablets, as dutasteride can be teratogenic to a male fetus if contact occurs with broken or crushed tablets.

Monitoring: For BPH, DHT and PSA levels are influenced by dutasteride; PSA declines by about half, so cancer screening interpretations should account for this adjustment. Regular monitoring of symptoms and side effects is recommended.