Dutasteride is a 5-alpha-reductase inhibitor: it blocks both forms of the enzyme that converts testosterone into dihydrotestosterone (DHT). It is sold as Avodart and as generic capsules.
Also known as: Avodart.
Avodart and generic dutasteride come as 0.5 mg soft gelatin capsules, the only strength on the FDA label.
The FDA Avodart label approves dutasteride for symptoms of benign prostatic hyperplasia (BPH) in men with an enlarged prostate, alone or with tamsulosin, at 0.5 mg once daily, swallowed whole with or without food. It is not approved for preventing prostate cancer, and it is not FDA approved for hair loss; that use is off-label.
The label says dutasteride cuts PSA by about 50% within 3 to 6 months, so after 3 months of use a PSA result should be doubled before comparing it with normal ranges. Men should not donate blood until at least 6 months after the last dose. Women who are or may be pregnant should not handle the capsules, because the drug is absorbed through the skin. In the REDUCE trial, high-grade (Gleason 8 to 10) prostate cancer was more common on dutasteride (1.0% vs 0.5%).
The FDA Avodart label gives a terminal half-life of about 5 weeks at steady state; Dose Track uses 35 days. Peak levels come 2 to 3 hours after a dose; the app uses 2.8 hours. Levels reach about 65% of steady state after 1 month and 90% after 3 months, and stay detectable for 4 to 6 months after stopping.
Numbers shown are the values Dose Track uses, listed only where they agree with the source above. Half-life varies from person to person and with injection site.