PROSCAR (finasteride), a synthetic 4-azasteroid compound, is a specific inhibitor of steroid Type II 5α-reductase, an intracellular enzyme that converts the androgen testosterone into 5α-dihydrotestosterone (DHT).

Finasteride is 4-azaandrost-1-ene-17-carboxamide, N-(1,1-dimethylethyl)-3-oxo-,(5α,17β)-. The empirical formula of finasteride is C₂₃H₃₆N₂O₂ and its molecular weight is 372.55. Its structural formula is:

Finasteride is a white crystalline powder with a melting point near 250°C. It is freely soluble in chloroform and in lower alcohol solvents, but is practically insoluble in water.

PROSCAR (finasteride) tablets for oral administration are film-coated tablets that contain 5 mg of finasteride and the following inactive ingredients: hydrous lactose, microcrystalline cellulose, pregelatinized starch, sodium starch glycolate, hydroxypropyl cellulose LF, hydroxypropyl methylcellulose, titanium dioxide, magnesium stearate, talc, docusate sodium, FD&C Blue 2 aluminum lake and yellow iron oxide.

What are the possible side effects of finasteride (Propecia, Proscar)?

Get emergency medical help if you have any of these signs of an allergic reaction:hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you notice any breast lumps, pain, nipple discharge, or other breast changes. These may be signs of male breast cancer.

Less serious side effects may include:

• impotence, loss of interest in sex, or trouble having an orgasm;
• abnormal ejaculation;
• swelling in your hands or feet;
• swelling or tenderness in your breasts;
• dizziness,...

What are the precautions when taking finasteride (Proscar)?

Before taking finasteride, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease, prostate cancer, infections, urinary problems.

Finasteride should not be used in children.

The drug can be absorbed through the skin. If the film coating of the tablet has been broken or the tablet crushed, it should not be handled by a woman who is pregnant or planning to become pregnant. Exposing a developing male infant to finasteride can result in abnormalities of the...