Dutasteride is a drug, which belongs to the group of drugs called 5-alpha-reductase inhibitors. This drug is used to treat men with enlarged prostate gland (benign prostatic hyperplasia) – a non-cancerous enlargement of the prostate gland, caused by excessive production of a hormone called dihydrotestosterone. When the prostate gland is growing, it can lead to problems with urination such as difficult urination and more frequent need to go to the toilet. It can cause also slower and weaker urine flow. If this condition is not treated, there is a risk of complete blockage of urine flow (acute urinary retention). This requires immediate treatment. In some cases, surgery is required to remove or reduce the prostate gland. The drug reduces dihydrotestosterone production and that helps to reduce the prostate gland and relieve the symptoms. As a result, the risk of acute urinary retention and the probability of surgery are reduced. This drug can be used with another medicine called tamsulosin (used to treat symptoms of an enlarged prostate).