Dutasteride in Young Women: Not Usually.

Dutasteride Prescribing for Pre-menopausal Women Requires Caution

If any drug is to be prescribed, the prescriber needs to know everything about the drug. So does the pharmacist who is dispensing the drug. The prescriber also needs to figure out what information is important to convey to the patient. If there are 10,000 things that the patient ‘could’ be told, which of these 10,000 things really should be relayed to the patient? The answer is mainly those pieces of information that are important to know about and the side effects that are common.

Dutasteride is a 5 alpha reductase inhibitor that is not formally approved for use in women. It is FDA approved for treated prostate problems in men and approved in South Korea for treating male balding. Dutasteride is sometimes used off label in many countries for treating androgenetic alopecia in men. In fact, studies have shown that dutasteride is more effective than finasteride in treating male pattern balding. It may or may not be associated with a higher risk of side effects such as sexual dysfunction.

The question often arises - if it’s used off label in treating male balding, can dutasteride be used off label in treating female genetic hair loss (i.e. female pattern hair loss)?

That answer is maybe - but maybe not.

Dutasteride for Female Hair Loss: Top 10 things to know

The following are my professional opinions and recommendations about the use of dutasteride for treating hair loss in women.

1 . Dutasteride is not FDA approved for women. That doesn’t it can’t be used for women it just means that it was formally approved for another use. Anyone using it needs to understand that. Many hair loss treatments we use are off label, so that fact alone is not alarming in any way.

2. Dutasteride is an oral medication that can be used to treat several types of hair loss in women, including post-menopausal female androgneetic alopecia and post menopausal frontal fibrosing alopecia. There’s evidence to back up the claim that it helps these conditions, albeit not everyone with these conditions.

3. Side effects of dutasteride in women include mood changes (depression), fatigue, weight gain, decreased sex drive, breast tenderness, breast enlargement, muscle soreness and rarely changes in blood counts.

4. Dutasteride has a long half life of 4-5 weeks. This simply means it stays around in the body a long time. In fact, dutasteride can even be detected in the body 6 months after stopping the drug.

5. Because of the long half-life, some women benefit from use once, twice or three times weekly. Daily use may not be required for all patients.

6. Because of the long half-life, women with pre-existing depression should not start dutasteride without careful discussion with their physician. It may worsen depression and if the drug is stopped it may take months to fully get out of the system. Other treatment options should be considered first.

7. Because of the long half-life, women with pre-existing sexual dysfunction should not start dutasteride without careful discussion with their physician. It may worsen sexual dysfunction and if the drug is stopped it may take months to fully get out of the system. Other treatment options should be considered first.

8. Because of the long half-life, pre-menopausal women who are planning to become pregnant at any time in the future should not use dutasteirde. My personal view is that dutasteride is medication that can be considered in post menopausal women and can be considered in pre-menopausal women over 40 who do not plan to have additional children or do not plan to have children provided it is used with contraception. Dutasteride, like finasteride, blocks conversion of testosterone to dihydrotestosterone (DHT) and by reducing levels of DHT may cause abnormalities in the external genitalia of the male fetus. The importance of using contraception and preventing pregnancy while using a 5 alpha reductase inhibitory drug can not be overemphasized. Unfortunately, this message may not be getting out to the public appropriately as some studies (i.e. Teirchert et al, 2017) have suggested that an extremely large proportion of women using finsateride and dutasteride may not using appoprirate contraception.

9. Given the limited number of studies in women, I do not recommend dutasteride for women with previous history of breast cancer or for women who have an elevated high risk for breast cancer. I particularly find the NIH Breast Cancer Risk Assessment Tool helpful in that regard and use it to help patients understand their baseline risk of breast cancer. Although there is no evidence that anti-androgens like spironolactone or finasteride increase the risk of breast cancer in women at low risk for developing breast cancer, we do not know whether women at very high risk for developing breast cancer place themselves at increased risk by using these drugs. It is unlikely but these studies have simply not been done.

10. Pre-menopausal women considering anti-androgen therapy may wish to discuss the use of other anti-androgens with their physician as well as other treatments. This would include spironolactone (Aldactone) and finasteride. Both of these drugs are also off label and both of these mediations are not to be used during pregnancy or by women who are trying to become pregnant. However, the shorter half life means that the drug is cleared rapidly from the body if side effects develop and if pregnancy is being considered in the near future.

REFERENCES

Teirchert M et al. Contraindicated use of 5‐alpha‐reductase inhibitors in women. Br J Clin Pharmacol. 2017 Feb; 83(2): 429–431.