Spironolactone for Hirsutism
Spironolactone is an effective treatment for hirsutism, with 100 mg daily demonstrating superior efficacy to other antiandrogens and producing significant clinical improvement within 2-6 months of treatment. 1, 2
Mechanism of Action
Spironolactone works through multiple pathways to reduce hirsutism 1, 3:
- Decreases testosterone production at the ovarian level 4
- Competitively inhibits testosterone and dihydrotestosterone binding to androgen receptors in the skin 1, 3
- May inhibit 5α-reductase and increase steroid hormone-binding globulin 1
Evidence for Efficacy
Clinical Outcomes
- Subjective improvement in hair growth occurs in approximately 77% of patients compared to 22% with placebo (RR 3.60) 1
- Significant reduction in Ferriman-Gallwey scores (mean difference -7.20 points) compared to placebo 2
- Clinical improvement becomes noticeable within 2 months, with maximal effect at 6 months and sustained benefit at 12 months 4
- 54% reduction in hirsutism scores after one year of treatment 5
Comparative Effectiveness
- Spironolactone 100 mg/day is superior to finasteride 5 mg/day and low-dose cyproterone acetate 12.5 mg/day up to 12 months after treatment ends 2
- Equally effective in women with polycystic ovary syndrome and idiopathic hirsutism 4
Dosing Recommendations
Starting Dose
Begin with 50 mg twice daily (100 mg/day total) on days 4-21 of the menstrual cycle 6, 7:
- Lower doses (50 mg daily) are effective but may take longer to show results 7
- Higher doses (200 mg daily) are more effective but carry significantly higher risk of menstrual irregularities 6, 4
Dose Titration
- If 100 mg twice daily causes intolerable side effects, reduce to 50 mg twice daily 6
- At 100 mg twice daily, 68% of patients require dose reduction due to side effects, primarily metrorrhagia 6
- At 50 mg twice daily, side effects are minimal and well-tolerated 6, 7
Side Effect Management
Menstrual Irregularities
Metrorrhagia with shortened cycles (14 days) occurs in 56% of women taking 100 mg twice daily 6:
- Concomitant use of combined oral contraceptives (COCs) is recommended to regulate menses and reduce menstrual irregularities 3
- Menstrual irregularities are less common in women using COCs 1
- Consider adding cyclical estrogen/progesterone therapy to continuous spironolactone 6
Other Common Side Effects
- Diuresis (limited to first few days of treatment) 4
- Breast tenderness and enlargement 1
- Fatigue and headache 1
- Dizziness 1
Contraception Requirements
Spironolactone is pregnancy category C and can cause feminization of male fetuses 3:
- Women of reproductive age must use effective contraception 1, 3
- COCs serve dual purpose: contraception and menstrual regulation 3
Safety Monitoring
Potassium Monitoring
Potassium monitoring is NOT routinely required in young, healthy women 3:
- Monitor potassium only in patients with risk factors: older age, hypertension, diabetes, chronic kidney disease, or concurrent use of ACE inhibitors, ARBs, or NSAIDs 1
- When monitoring is indicated: check within 3 days, at 1 week, monthly for 3 months, then every 3 months 8
Concomitant Use with Drospirenone-Containing COCs
Spironolactone can be safely combined with drospirenone-containing COCs without increased risk of hyperkalemia 3:
- No significant elevations in serum potassium were found in studies 3
- No additional side effects requiring treatment discontinuation 1, 3
Treatment Timeline
- Initial improvement: 2-3 months 4
- Maximal effect: 6 months 4
- Sustained benefit: Maintained at 12 months and beyond 2, 4
- Treatment duration: Minimum 6-12 months recommended for full assessment 2, 5
Combination Therapy Approach
The combination of spironolactone with a COC is the most effective medical approach 1:
- COCs decrease free testosterone by 40-50% on average 3
- Spironolactone blocks peripheral androgen action 4
- Combined therapy addresses both hormonal production and peripheral effects 1
Mechanical Hair Removal
Concomitant mechanical hair removal (plucking, shaving, waxing, electrolysis, laser) is usually necessary 1: