Dutasteride is a medication used for the treatment of benign prostatic hyperplasia (BPH) also known as an enlarged prostate. Dutasteride belongs to a class of medication called 5-alpa reductase inhibitors. Male hormone dihydrotestosterone (DHT) is primarily responsible for development and enlargement of the prostate gland. Testosterone is converted into DHT by 5-alpha reductase enzyme. Dutasteride blocks 5-alpha reductase enzyme and prevents excessive DHT production in the prostate gland. This delays the progression of an enlarged prostateand improves symptoms of BPH.