Dutasteride

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DUTASTERIDE

How Supplied

Oral: dutasteride -0.5 mg capsule once daily

-not approved yet for alopecia

Availability

Avodart (trade name)- approved in 2002
Generics available

Mode of Action

Dutasteride is a 5-alpha reductase inhibitor somewhat similar to finasteride; however, dutasteride blocks both 5AR l and 5AR ll whereas finasteride is only a 5AR ll inhibitor. It lowers serum DHT up to 95% compared to 66% for finasteride. In addition, its half-life in the serum is much longer than for finasteride- 5 weeks for dutasteride compared to 6-8 hrs for finasteride.

Effectiveness

Studies have shown dutasteride to be equal to and usually slightly greater in effect for hair growth as compared to finasteride. 2.5 mg dutasteride daily has shown a moderately higher growth than 0.5mg dutasteride daily.

Side Effects

As with finasteride, dutasteride should not be taken or handled by a women who is pregnant or who may become pregnant because of the drug’s potential for causing abnormal development of a fetus. Side effects of dutasteride are similar to those reported for finasteride—decreased libido (sex drive), erectile dysfunction, male breast enlargement and psychological depression.

In one double-blind study, 2/70 patients on 0.5mg daily had decreased libido 2/70 had impotence. 3/70 on a placebo developed impotence. 9/71 taking dutasteride 2.5mg daily had impotence, indicating a correlation with dose size.

Fertility: Another study showed a 25-28% decrease in sperm count in a one year trial. 6 months after discontinuing dutasteride the sperm count was still decreased by 23%. Semen volume followed these same percentages. The sperm morphology appeared normal.

Drug interactions reported from use of dutasteride include interference with some antibiotics, some anti-depression and anti-anxiety medications, and some drugs used to treat HIV/AIDS

Note

Dutasteride is a reasonable alternative to finasteride but some doctors are reluctant to use it because of its long half-life in the body. If wanting to use a 5AR inhibitor while starting a family, finasteride is the better choice. If the patient has a naturally low sperm count, it would be wise to avoid both drugs while trying to achieve pregnancy.