Can finasteride (generic name) be used in women, particularly those of childbearing age or with specific conditions like hirsutism or female pattern hair loss?

Finasteride Use in Women

Finasteride can be used in select populations of women, but is absolutely contraindicated in women of childbearing potential due to severe teratogenic risk to male fetuses. Postmenopausal women and women with specific hyperandrogenic conditions may benefit from finasteride therapy with appropriate counseling and precautions.

Absolute Contraindications

Women who are pregnant or may potentially become pregnant must never use finasteride in any form. 1 The FDA explicitly states that finasteride may cause abnormal development of external genitalia in male fetuses based on animal studies and mechanism of action. 1

• Pregnant women should not even handle crushed or broken finasteride tablets; if contact occurs, the area must be washed immediately with soap and water. 1
• Women of childbearing age should not donate blood until 6 months after the last dose due to risk to pregnant females. 2
• The American Academy of Dermatology reinforces that women of childbearing potential should avoid all finasteride formulations due to severe teratogenic risk. 3

Approved Clinical Uses in Women

Hirsutism and Polycystic Ovary Syndrome (PCOS)

The American Academy of Family Physicians recommends finasteride as an effective antiandrogen for hirsutism in PCOS patients, but it must always be combined with oral contraceptives rather than used as monotherapy. 2 This combination addresses both contraception requirements and therapeutic efficacy.

• Finasteride should be considered as an alternative antiandrogen when spironolactone is contraindicated or not tolerated, at a dose of 5 mg daily. 2
• Antiandrogens must always be combined with ovarian suppression (oral contraceptives) for optimal efficacy, and therapy must continue indefinitely unless underlying PCOS is corrected. 2
• Clinical trials demonstrate finasteride lowers hirsutism scores by 30-60% in most trials and decreases average hair diameter. 4
• Randomized controlled trials specifically recommend finasteride treatment for women with hirsutism or polycystic ovarian syndrome. 5

Female Pattern Hair Loss (FPHL)

Postmenopausal women may use finasteride off-label for hair loss with careful consideration of limited efficacy data. 2, 3

Evidence for Postmenopausal Women:

• A study of normoandrogenic postmenopausal women treated with 2.5-5 mg/day oral finasteride showed improved scalp hair by all evaluation techniques, with decreased hair loss, increased hair growth, and improved appearance. 6
• In normoandrogenic Asian women with FPHL treated with 5 mg/day finasteride for 12 months, hair density increased significantly from 90±22/cm² to 107±23/cm² (P<0.001), and hair thickness increased from 64±11 μm to 70±9 μm (P=0.02). 7
• Global photographs showed 81.4% of patients improved (57 slightly, 10 moderately, 4 greatly improved) after 12 months of treatment. 7

Evidence for Women with Hyperandrogenism:

• Four cases of hair loss with characteristics of both male and female patterns in women with hyperandrogenism showed improved or stabilized alopecia with finasteride, with improvements seen after 6 months to 2.5 years. 8
• This finding supports that finasteride improves pattern hair loss in women with hyperandrogenism but may not affect postmenopausal women with female pattern hair loss without hyperandrogenism, suggesting different pathophysiologies. 8

Special Populations: Adolescent Females

Finasteride may be suggested in select cases for adolescent female patients with hidradenitis suppurativa, particularly those with endocrine comorbidities like polycystic ovary syndrome. 2 However, careful assessment of benefits and risks is crucial in this population, as recommended by the Endocrine Society. 2

Dosing Recommendations

Based on systematic review of 65 studies involving 2,683 patients:

• Oral finasteride doses range from 0.5 to 5 mg/day. 5
• Most common treatment duration is 6-12 months (57.6% of studies). 5
• Finasteride is typically used as monotherapy (88.9%) and for continuous use (96.4%). 5
• For hirsutism in PCOS: 5 mg daily combined with oral contraceptives. 2
• For postmenopausal FPHL: 2.5-5 mg/day. 6, 7

Adverse Effects and Safety Considerations

Finasteride demonstrates fewer adverse effects compared to other antiandrogens in comparative trials. 4

Common adverse events (occurring in 4.6% of patients in one study):

• Headache 7
• Menstrual irregularity 7
• Dizziness 7
• Increased body hair growth 7

These adverse events are typically mild and resolve spontaneously. 7 However, sexual side effects may persist beyond drug discontinuation in some patients. 2

Additional considerations:

• Risk of gynecomastia is 0.5-2.2%, which may require surgical correction. 3
• Finasteride reduces PSA levels by approximately 50%, requiring adjustment of prostate cancer screening thresholds if relevant. 3

Clinical Algorithm for Prescribing Finasteride to Women

1. Verify reproductive status: Confirm patient is postmenopausal OR has reliable contraception if premenopausal
2. For premenopausal women: Prescribe oral contraceptives concurrently (mandatory, not optional) 2
3. Assess indication: Hirsutism/PCOS (strongest evidence) vs. FPHL (moderate evidence in postmenopausal women)
4. Initiate dosing: 5 mg daily for hirsutism; 2.5-5 mg daily for FPHL 2, 6, 7
5. Counsel on timeline: Expect improvement in 6-12 months for hirsutism, 12 months for hair loss 2, 7
6. Monitor response: Clinical assessment at 6 and 12 months 7
7. Continue indefinitely: Unless underlying condition resolves 2

Critical Pitfalls to Avoid

• Never prescribe finasteride to women of childbearing potential without concurrent reliable contraception (oral contraceptives preferred for dual benefit). 2, 1
• Do not use finasteride as monotherapy in premenopausal women—always combine with oral contraceptives. 2
• Avoid oral contraceptives containing androgenic progestins (norethisterone derivatives, levonorgestrel) as they can worsen hirsutism. 9
• Remember that efficacy data for FPHL in normoandrogenic postmenopausal women remains limited compared to hirsutism/PCOS. 2, 5
• Counsel patients that improvement requires 6-12 months of continuous therapy. 2, 7