Is there data available on systemic absorption of topical finasteride in treating females with male pattern baldness? Is there any data related to oral or topical finasteride use in female patients with a history of Hormone Receptor-positive (HR+) breast cancer and risk of recurrence?

Comment by InpharmD Researcher

While the systemic absorption of topical finasteride has yet to be evaluated in females with male pattern baldness, topical finasteride is generally deemed to have high skin penetration and low systemic absorption. Data appear to support the use of finasteride for the treatment of baldness in females, but data on the topical formulation are lacking. There also appears to be a paucity of data evaluating the use of oral or topical finasteride in female patients with a history of breast cancer and risk of recurrence; data for finasteride in breast cancer is limited to males.

Background

A 2019 systematic review evaluated the efficacy and use of finasteride in women with a focus on dosage, length of treatment, and conditions that can benefit from finasteride therapy. A total of 65 studies (published randomized controlled trials [RCTs], prospective cohort studies, retrospective studies, and case reports) involving 2,683 patients were included in the final analysis. The majority of the female patients included in the studies were treated with finasteride for hirsutism (48.7%). The efficacy of finasteride use on female pattern hair loss (FPHL) was assessed in 34.7% of RCTs; while other forms of hair loss such as alopecia, lichen planopilaris, and frontal fibrosing alopecia were studied, no RCTs that evaluated finasteride therapy for those conditions were identified. The analysis of other prospective and retrospective studies demonstrated that finasteride may improve hair loss in women with FPHL or frontal fibrosing alopecia. Evidence from RCTs suggested that finasteride treatment can improve hirsutism scores in women with hirsutism or idiopathic hirsutism secondary to polycystic ovarian syndrome. In general, the doses of oral finasteride ranged from 0.5 to 5 mg/day in females between the ages of 6 to 88 years with the length of treatment ranging from 6 to 12 months (57.6%). Monotherapy was used in 88.9% of included finasteride patients, and a continuous frequency of use was implemented in 96.4% of finasteride patients. Several recommendations regarding finasteride use in women, along with the corresponding references, were made by the authors and are summarized in Table 1. [1]

A 2015 Cochrane systematic review investigated interventions for hirsutism in women with polycystic ovary syndrome, idiopathic hirsutism, or idiopathic hyperandrogenism. Two included studies suggested a difference in reduction of Ferriman‐Gallwey hirsutism assessment scores for finasteride 5 mg to 7.5 mg daily compared to placebo (mean difference [MD] ‐5.73, 95% confidence interval [CI] ‐6.87 to ‐4.58), however, the authors determined this very low quality of evidence was unlikely to be clinically meaningful. Two studies were also included comparing finasteride vs. spironolactone, finding similar effectiveness (MD 1.49, 95% CI ‐0.58 to 3.56 vs. MD 0.40, 95% CI ‐1.18 to 1.98). This was also considered to be low-quality data, and ultimately, the authors determined that finasteride showed inconsistent results, precluding any firm conclusions. [2]

Another 2018 systematic review and meta-analysis compared pharmacologic treatments for hirsutism in women. A total of 43 RCTs were analyzed and six drug classes or combinations of classes were used, including oral contraceptive pills (OCPs), antiandrogen, insulin sensitizer, OCPs plus antiandrogen, OCPs plus insulin sensitizer, and antiandrogen plus insulin sensitizer. When compared with placebo, antiandrogen monotherapy with finasteride presented with a significant reduction in hirsutism with an overall effect size of −1.48 (95% CI −2.18 to −0.78, p<0.05). While antiandrogen monotherapy with flutamide, finasteride, and spironolactone was demonstrated to be more effective than placebo, all these agents had similar efficacy when compared to each other. A combination of OCPs with finasteride demonstrated superior efficacy in comparison with placebo with an effect size of −1.64 (95% CI −2.72 to −0.55). It should be noted that the risk of bias in the included trials was high. Furthermore, as many of the studies had important methodological limitations, the precision of the results remains limited, and the interpretation of data should be done with caution. [3]

In general, the ideal formulation of topical finasteride has high skin penetration and low systemic absorption. Despite this, studies on the efficacy of topical finasteride in females are lacking. [4]

Literature Review

A search of the published medical literature revealed 3 studies investigating the researchable question:

Level of evidence

X - No data Read more→

Please see Tables 1-3 for your response.

Summary of recommendations for finasteride treatment in women
Recommendation	Grade of recommendation	Quality of evidence	Source
Finasteride can be used to treat females with IH or hirsutism secondary to PCOS	1	A	Faloia et al.; Petrone et al.; Bayram et al.; Bayram et al.; Lakryc et al.; Tartagni et al.; Tartagni et al.
Topical finasteride can be used to treat women with IH	1	A	Lucas; Tahvilian et al.; Alijanpour
For shorter courses of treatment, finasteride is more effective than flutamide in treating females with IH or hirsutism secondary to PCOS	1	A	Falsetti et al.
Medium-dose finasteride (2.5 mg/day) is just as effective as high-dose finasteride (5 mg/day) for treating females with IH or hirsutism secondary to PCOS	1	A	Bayram et al.
Finasteride is just as effective as flutamide, spironolactone, and CPA+EE for treating females with IH or hirsutism secondary to PCOS	1	A	Fruzzetti et al.; Moghetti et al.; Beigi et al.
Finasteride is less effective than flutamide, spironolactone, CPA+EE, and GnRH in treating females with IH or hirsutism secondary to PCOS	1	A	Erenus et al.; Sahin et al.; Falsetti et al.; Venturoli et al.; Bayhan et al.; Muderris et al.; Lumachi et al
Combination therapy of finasteride and spironolactone or finasteride and CPA+EE is more effective than monotherapy in treating IH or hirsutism secondary to PCOS	1	A	Tartagni et al.; Sahin et al.; Unluhizarci et al.; Kelestimur et al.
Combination therapy of finasteride and rFSH can be used to treat females with PCOS	1	A	Tartagni et al.
Finasteride does not alter the volume and number of cysts in female ovaries	1	A	Arie et al.
Finasteride is less effective than flutamide and CPA+EE in treating females with acne	1	A	Carmina and Lobo
AR-CAG repeat numbers can predict finasteride efficacy in Caucasian females with FPHL	1	A	Keene et al.
Lower-dose finasteride (1 mg/day) and high-dose finasteride (5 mg/day) are not effective for treating hair loss in females with FPHL	1	A	Whiting et al.; Price and Roberts et al.; Altomare et al.; Carmina and Lobo
Topical finasteride is not effective for treating hirsutism	2A	A	Price and Allen et al.
Combination therapy of finasteride and flutamide is more effective than monotherapy in treating hirsutism	2A	B	Unluhizarci et al.
Finasteride can improve symptoms in females with acne and alopecia	2A	B	Kohler et al.
AR-CAG repeat numbers cannot predict finasteride efficacy in Japanese females with FPHL	2A	B	Yamazaki et al.
Low to high-dose finasteride (1.25–5 mg/day) can improve hair loss in females with FPHL	2A	B	Shum et al.; Thai et al.; Yeon et al.; Boychenko et al.; Oliveira-Soares et al.; Boersma et al.
Low-dose finasteride (1.25 mg/day) or combination therapy of finasteride and minoxidil is not effective for treating hair loss in females with FFA	2A	B	Rallis et al.; Kim et al.
Finasteride can improve hair loss in females with FFA	2A	B	Tosti et al.; Ladizinski et al.; Vano-Galvan et al.
Finasteride therapy does not alter follicular development or ovulation	2A	B	Wong et al.
Finasteride can cause mood disturbances in females with FPHL	2B	B	Altomare et al.
Finasteride can improve hair loss in female-to-male transgender patients with FPHL	2B	B	Moreno-Arrones et al.
Combination therapy of finasteride, cetirizine, and a topical medication can mildly improve symptoms of CLPP and FFA	2B	B	Mardones et al.
Finasteride can resolve SRF in females with central serous chorioretinopathy	2B	B	Moisseiev et al.
Combination therapy of finasteride, minoxidil, and triamcinolone acetonide can improve hair loss in females with FFA	2B	C	Moreno-Ramirez et al.
Finasteride can improve symptoms in females with HS	2B	C	Farrell et al.; Joseph et al.; Khandalavala; Mota et al.
Finasteride can be used to alleviate chronic migraines in females	2B	C	Check et al.
Finasteride cessation can stop seizures in females	2B	C	Pugnaghi et al.
Finasteride therapy prior to pregnancy can result in successful full-term pregnancy and live birth	2B	C	Tartagni et al.
Unintentional finasteride during early pregnancy can cause aphalangia in a newborn girl	2B	C	Sallout and Alwadi
According to criteria by Robinson et al: Grade of recommendation: 1, strong recommendation; high-quality, patient-oriented evidence; 2A, weak recommendation; limited-quality, patient-oriented evidence; 2B, weak recommendation; low-quality evidence. Quality of evidence: A, systematic review/meta-analysis; randomized clinical trials with consistent findings; all-or-none observational studies; B, systematic review/ meta-analysis of lower-quality clinical trials or studies with limitations and inconsistent findings; lower-quality clinical trial; cohort study; case-control study; C, consensus guidelines, usual practice, expert opinion, case series. AGA, androgenetic alopecia; AR-CAG, androgen receptor cytosine, adenine, guanine; CLPP, classic lichen planopilaris; CPA, cyproterone acetate; CSCR, central serous chorioretinopathy; EE, ethinyl estradiol; FAGA, female androgenic alopecia; FFA, frontal fibrosing alopecia; FPHL, female pattern hair loss; HS, hidradenitis suppurativa; IH, idiopathic hirsutism; PCOS, polycystic ovary syndrome; SRF, subretinal fluid.

References:

Adapted from:
Hu AC, Chapman LW, Mesinkovska NA. The efficacy and use of finasteride in women: a systematic review. Int J Dermatol. 2019;58(7):759-776. doi:10.1111/ijd.14370

The effectiveness of finasteride and dutasteride used for 3 years in women with andorgenetic alopecia
Design	Retrospective cohort study N=120
Objective	To evaluate the effectiveness of finasteride and dutasteride on hair loss in women with androgenetic alopecia over a period of 3 years
Study Groups	Finasteride (n=60) Dutasteride (n=60)
Inclusion criteria	Clinical diagnosis of Ludwig grade 1 or grade 2 androgenetic alopecia confirmed by the presence of thin hair on a microscopic picture, continuous treatment for at least 3 years (assessed by regular filling of the prescription)
Exclusion criteria	N/A
Methods	Patients received either finasteride 1.25 mg daily or dutasteride 0.15 mg daily. An increase in hair thickness was obtained by subtracting the pretreatment hair thickness from that measured after 3 years. Treatment was considered effective if the hair thickness increase was equal to, or greater than zero.
Duration	10 years
Outcome Measures	Hair thickness
Baseline Characteristics		Finasteride (n=60)	Dutasteride (n=60)
	Age, years < 50 > 50	30 (50%) 30 (50%)	30 (50%) 30 (50%)
Results		HTI<0 mm	HTI≥0 mm	Effectiveness
	Finasteride 1.25 mg <50 years ≥50 years All ages	5 6 11	25 24 49	83.3% 80% 81.7%
	Dutasteride 0.15 mg <50 years ≥50 years All ages	5 5 10	25 25 50	83.3% 83.3% 83.3%
	Overall	21	99	82.5%
	HTI=hair thickness increase All hair thickness increases were statistically significantly different from 0 in both age categories and at all sites of the scalp (P<0.05), except for the increase in the age category above 50 years by dutasteride at the frontal site. Dutasteride had higher means for users in the age group under 50 at the center of the scalp and the vertex (P<0.05).
Adverse Events	Not disclosed
Study Author Conclusions	Finasteride 1.25 mg and dutasteride 0.15 mg given daily for 3 years effectively increased hair thickness and arrested further deterioration in women with androgenetic alopecia.
InpharmD Researcher Critique	The study provides evidence that dutasteride may be better than finasteride for increasing hair thickness in women with alopecia but there was no control or double-blind data and more studies are needed for conclusive evidence. Additionally, only hair thickness was measured instead of growth density.

References:

Boersma IH, Oranje AP, Grimalt R, Iorizzo M, Piraccini BM, Verdonschot EH. The effectiveness of finasteride and dutasteride used for 3 years in women with androgenetic alopecia. Indian J Dermatol Venereol Leprol. 2014;80(6):521-5.

Clinical and endocrine effects of finasteride, a 5 alpha-reductase inhibitor, in women with idiopathic hirsutism
Design	Randomized, single-blind study N=18
Objective	To evaluate the effects of long-term administration of finasteride on hirsutism score, basal gonadotropin and androgen secretion in women with idiopathic hirsutism
Study Groups	Finasteride (n=9) Placebo (n=9)
Inclusion criteria	Women with moderate to severe hirsutism
Exclusion criteria	Acne-seborrhea, clinical signs of hyperandrogenism
Methods	Patients were randomized to receive finasteride 7.5 mg or placebo daily for 9 months.
Duration	9 months
Outcome Measures	Reduction in hirsutism score, biomarker levels
Baseline Characteristics		Finasteride (n=9)	Placebo (n=9)
	Age, years	20.9 ± 0.62	20.2 ± 0.62
	Ferriman-Gallway score	21.8 ± 0.81	19.0 ± 1.57
Results		Placebo (n=9)	Finasteride (n=9)
	Unbound testosterone, pg/mL Baseline 3 months 6 months 9 months	2.7 ± 0.08 2.88 ± 0.14 2.82 ± 0.1 2.92 ± 0.09	2.97 ± 0.13 2.90 ± 0.13 2.97 ± 0.11 3.04 ± 0.08
	The Ferriman and Gallwey hirsutism score of patients treated with finasteride was statistically significant when compared to placebo (p<0.05), but there was no significant change in the placebo group.
Adverse Events	Not disclosed
Study Author Conclusions	Finasteride decreased the hirsutism score of patients affected by idiopathic hirsutism with few sides during treatment.
InpharmD Researcher Critique	A limitation of the study is the small sample size. This study did not report individual Ferriman and Gallwey hirsutism scores other than the baseline.

References:

Ciotta L, Cianci A, Calogero AE, et al. Clinical and endocrine effects of finasteride, a 5 alpha-reductase inhibitor, in women with idiopathic hirsutism. Fertil Steril. 1995;64(2):299-306.