Proscalpin (Finasteride) It is used to relieve symptoms of an enlarged prostate gland (benign prostatic hyperplasia or BPH). It is also used for the treatment of male pattern hair loss (androgenetic alopecia). How it works (Spain) Finasteride belongs to the class of medications called 5-alpha reductase inhibitors. It works by inhibiting the conversion of testosterone to the more potent androgen, dihydrotestosterone. This leads to a reduction in the size of the prostate, with improvement in urinary flow rate and obstructive symptoms. It also reduces androgen activity in the scalp which stops hair growth. Dosage Always follow your doctor's instructions regarding dosage and duration. As monotherapy, In benign prostatic hyperplasia: 5 mg / day. In male pattern hair loss: 1 mg/day. As combined therapy: In benign prostatic hyperplasia: 5 mg / day with doxazosin (alpha blocker). Common side effects Decreased ejaculate volume, decreased sexual desire (libido), inability to achieve an erection (impotence), mood changes with depressive symptoms, erection problems (erectile dysfunction), allergic reactions including skin rash, itching of the skin, Rash and swelling of the lips and face in Spain, tenderness and enlargement of the breasts (gynecomastia), testicular pain, infertility, palpitations, increased liver enzyme.