Monday Pharmaceutical Mystery: January 27

You are entering several dermatology prescriptions for your 58-year-old female patient, DT, that were sent electronically to your queue. After processing prescriptions for mupirocin ointment ,and mometasone cream, you realize the third prescription is for finasteride (Proscar) 5 mg with the sig: take 1 tablet by mouth daily.

Usually, finasteride is used in men for the treatment of benign prostatic hyperplasia (BPH). You are sure this was a mistake and that the dermatologist mistakenly clicked on finasteride instead of another drug.

Mystery: Why is DT, a female, taking finasteride, which you have only seen prescribed in male patients?

Solution: You call the prescriber’s office to ask about the prescription, and the nurse confirms the drug and dose as well as the indication. DT is taking finasteride to treat hair loss.

It is important to note that the use of finasteride in women is off-label, and is not currently approved by the FDA for female use. The drug is indicated for use only in men.

Currently, finasteride 5 mg is indicated as monotherapy in men with symptomatic BPH to improve symptoms, reduce the risk of acute urinary retention, and reduce the risk of the need for surgery. It is also indicated in combination with an alpha-blocker to reduce the risk of symptomatic BPH progression.¹

Finasteride 1 mg (Propecia) also is indicated for the treatment of male pattern hair loss. Hair loss in women is not indicated.²

Although finasteride is only indicated for use in male patients, it has been used in women. Due to the risk of birth defects to a male fetus, finasteride is contraindicated in pregnant women, and in women of childbearing age. Pregnant women or women of childbearing age also should not handle crushed or broken finasteride tablets.¹

In a study of finasteride 1 mg in postmenopausal women for hair loss, it was found that after 12 months, finasteride did not increase hair growth or slow the progression of thinning.³ Consequently, 5 mg was concluded to be a more effective dose in women, although it is still not indicated for women at any dose.⁴

A review of 20 peer-reviewed articles found that few adverse effects related to sexual dysfunction, such a lower libido, occurred in women taking finasteride for hair loss. Adverse effects that did occur were mild and disappeared over time, even with continuation of treatment.⁵

It is important to remember that if you see a prescription for finasteride for a female patient, that you ensure the patient is not pregnant or of childbearing age, and also verify the drug, dose, and indication with the prescriber for the off-label use of finasteride.

REFERENCES

• DailyMed. Proscar. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=7c01f541-1c88-400c-41a9-7cbb9dee50c0 Accessed January 20, 2020.
• DailyMed. Propecia. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=4e07adb4-7807-47d3-b9a9-2332a3047410 Accessed January 20, 2020.
• Price VH, Roberts JL, Hordinsky M, et al. Lack of efficacy of finasteride in postmenopausal women with androgenetic alopecia. https://www.ncbi.nlm.nih.gov/pubmed/11050579 J Am Acad Dermatol. 2000 Nov;43(5 Pt 1):768-76.
• Yeon JH, Jung JY, Choi JW, et al. 5 mg/day finasteride treatment for normal androgenic Asian women with female pattern hair loss. J Eur Acad Dermatol Venereol. 2011 Feb;25(2):211-4. doi: 10.1111/j.1468-3083.2010.03758.x. Epub 2010 Jun 21.
• Oliveira-Soares R, André MC, Peres-Correia M. Adverse effects with finasteride 5 mg/day for patterned hair loss in premenopausal women. Int J Trichol [serial online] 2018 [cited 2020 Jan 5];10:48-50. http://www.ijtrichology.com/text.asp?2018/10/1/48/223388