finasteridi

Finasteride is a synthetic drug that acts as a 5-alpha-reductase inhibitor, primarily targeting the type II isoenzyme responsible for converting testosterone into dihydrotestosterone (DHT). By lowering DHT levels, finasteride reduces androgenic activity in tissues such as the prostate and hair follicles.

The drug is approved for two main clinical uses. For benign prostatic hyperplasia (BPH), finasteride is prescribed at 5 mg once daily. For male pattern hair loss, it is typically given at 1 mg daily. In both cases, some patients experience slowed hair loss and, over time, potential regrowth or symptom improvement, with effects usually taking several months to become evident. Finasteride lowers serum DHT by a substantial margin and also reduces scalp DHT, which is linked to its therapeutic effects in hair loss.

Common adverse effects relate to its antiandrogenic action and may include decreased libido, erectile dysfunction, and ejaculation disorders. Gynecomastia can occur, and a small number of users report persistent sexual side effects even after stopping the drug. The risk of persistence is debated and is a consideration in weighing benefits and harms. Pregnant women or those who may become pregnant should avoid handling broken or crushed finasteride tablets, as exposure can cause feminization of a male fetus. Safety monitoring is advised for men taking finasteride, particularly with long-term use.

Finasteride is administered orally and is metabolized in the liver with renal excretion of metabolites. It was approved by regulatory authorities in the 1990s for BPH (Proscar) and male pattern hair loss (Propecia).