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A first-of-its-kind network meta-analysis compared the relative efficacies of oral finasteride and oral and topical minoxidil in female pattern hair loss (PHL). Efficacy appeared to be considerably dose-dependent for both agents.

The analysis, published in the , assessed 24 weeks of data from 10 different regimens from 13 separate trials. Listed in decreasing order of surface under the cumulative ranking (SUCRA) scores: 5 mg daily of finasteride for 24 weeks (SUCRA = 95.7%); 5% topical minoxidil solution twice daily (SUCRA = 89.5%); 1 mg daily of minoxidil (SUCRA = 78.1%); 5% topical minoxidil foam 1 half-capful daily (SUCRA = 66.5%); 3% topical minoxidil solution 1 mL twice daily (SUCRA = 45.1%); 2% topical minoxidil solution 1 mL twice daily (SUCRA = 44.6%); 5% topical minoxidil solution 1 mL (SUCRA = 41.7%); 0.25 mg daily of minoxidil (SUCRA = 35.5%); 1.25 mg daily of finasteride (SUCRA = 24.8%); and 1 mg daily of finasteride (SUCRA = 4.3%).

The research, conducted by an international team of researchers, was led by Aditya Gupta MD, PhD, professor of dermatology at the University of Toronto School of Medicine. The following study excerpts have been edited for length and clarity.

What was the impetus for this report?

Minoxidil and the 5-alpha reductase inhibitors, specifically dutasteride and finasteride, are usually used to treat PHL, but evidence on the relative effectiveness of these drugs is far less for women than for men.

Female PHL is quite common, with an estimated prevalence rate of 50%. Female PHL can occur at any age after puberty and its prevalence increases with age. Effective treatments for female PHL are limited, and there is a lack of well-designed randomized controlled trials investigating potential therapies.

In the current analysis, researchers sought to determine the relative efficacy of minoxidil and finasteride -- in varying dosages and administrative routes -- on change in total hair density at 24 weeks in women with PHL.

What were the key findings?

Researchers reported a significant dosage effect in many regimens. For example, 5% topical minoxidil solution at 1 mL twice a day for 24 weeks was significantly (P<0.05) more efficacious than 5% topical minoxidil solution at 1 mL once a day for 24 weeks (mean difference [MD] = 13.85 hairs/cm², 95% CI 9.1-18.7). Likewise, 5% topical minoxidil solution administered twice daily for 24 weeks was significantly (P<0.05) more efficacious than 2% topical minoxidil solution administered at 1 ml twice a day for 24 weeks (MD = 13.3 hairs/cm², 95% CI 7.4-19.5).

Researchers also found higher doses of finasteride to be more efficacious; 5 mg of finasteride once a day for 24 weeks was far more effective than 1 mg finasteride once a day for 24 weeks (MD = 28.2 hairs/cm², 95% CI 19.1-37.3).

Despite identifying significant dosage effects among some regimens, some pairwise comparisons showed no significant difference. For instance, 3% topical minoxidil solution at 1 mL twice a day for 24 weeks (SUCRA = 45.1%) was not significantly different from 2% topical minoxidil solution at 1 mL twice a day for 24 weeks (SUCRA = 44.6%).

Likewise, the effect of 1 mg of minoxidil once a day for 24 weeks (SUCRA = 78.1%) and 0.25 mg minoxidil once daily for 24 weeks (SUCRA = 35.5%) were not significantly different.

What is a key take-home message for clinicians?

In this analysis, researchers evaluated monotherapies to treat female PHL. In reality, however, treatments are often combined for maximal benefit while keeping potential adverse effects to a minimum. For example, an oral therapy such as finasteride may be combined with a topical therapy with a different mechanism of action, such as minoxidil.

Are there any final words on this analysis and on female PHL treatments from this paper?

First, the team's systematic search did not identify studies evaluating the use of dutasteride to treat female PHL.

Second, the use of finasteride (oral and topical) and oral minoxidil to treat female pattern PHL is off label in the U.S. Topical finasteride is neither approved nor commercially available in the US. However, there is a commercially available topical finasteride preparation approved in some European countries and South Korea. It would be interesting to be able to compare the efficacy of topical finasteride to treat female pattern PHL against oral finasteride, and the oral and topical preparations of minoxidil.