Dutasteride, sold under the brand name Avodart among others, is a medication primarily used to treat the symptoms of an enlarged prostate. A few months may be required before benefits occur. It is also used for scalp hair loss in men and as a part of hormone therapy in transgender women. It is taken by mouth.
Common side effects include sexual problems, breast tenderness, and breast enlargement. Other side effects include an increased risked of certain forms of prostate cancer, depression, and angioedema. Exposure during pregnancy, including use by the partner of a pregnant women may result in harm to the baby. Dutasteride is a 5α-reductase inhibitor, and hence is a type of antiandrogen. It works by decreasing the production of dihydrotestosterone (DHT), an androgen sex hormone.
Dutasteride was patented in 1993 by GlaxoSmithKline and was approved for medical use in 2001. It is available as a generic medication. A month supply in the United Kingdom costs the NHS about £12 as of 2019. In the United States, the wholesale cost of this amount is about $6.66. In 2016, it was the 274th most prescribed medication in the United States with more than a million prescriptions.Dutasteride is used for treating benign prostatic hyperplasia (BPH); colloquially known as an "enlarged prostate". It is approved by the Food and Drug Administration (FDA) in the U.S. for this indication.A 2010 Cochrane review found a 25–26% reduction in the risk of developing prostate cancer with 5α-reductase inhibitor chemoprevention. However, 5α-reductase inhibitors have been found to increase the risk of developing certain rare but aggressive forms of prostate cancer (27% risk increase), although not all studies have observed this. There is insufficient data to determine if they have an effect on the overall risk of death from prostate cancer.Dutasteride is approved for the treatment of male androgenetic alopecia in South Korea and Japan at a dosage of 0.5 mg per day. It has been found in several studies to improve hair growth in men more rapidly and to a greater extent than 2.5 mg/day finasteride. The superior effectiveness of dutasteride relative to finasteride for this indication is considered to be related to the fact that the inhibition of 5α-reductase and consequent prevention of scalp DHT production is more complete with dutasteride. Dutasteride has also been used off-label in the treatment of female pattern hair loss.Although no reports specific to dutasteride currently exist, 5α-reductase inhibitors like finasteride have been found to be effective in the treatment of hirsutism (excessive facial and/or body hair growth) in women. In a study of 89 women with hyperandrogenism due to persistent adrenarche syndrome, finasteride produced a 93% reduction in facial hirsutism and a 73% reduction in bodily hirsutism after 2 years of treatment. Other studies using finasteride for hirsutism have also found it to be clearly effective. Dutasteride may be more effective than finasteride for this indication due to the fact that its inhibition of the 5α-reductase enzyme is comparatively more complete.Dutasteride is sometimes used as a component of hormone therapy for transgender women in combination with an estrogen and/or another antiandrogen like spironolactone. It may be useful for treating scalp hair loss or in those who cannot tolerate spironolactone.Women who are or who may become pregnant should not handle the drug. Dutasteride can cause birth defects, specifically ambiguous genitalia and undermasculinization, in male fetuses. This is due to its antiandrogenic effects and is seen naturally in 5α-reductase deficiency. As such, women who are pregnant should never take dutasteride. People taking dutasteride should not donate blood to prevent birth defects if a pregnant women receives blood and, due to its long elimination half-life, should also not donate blood for at least 6 months after the cessation of treatment.
Children and people with known significant hypersensitivity (e.g., serious skin reactions, angioedema) to dutasteride should not take dutasteride.