Starting Dose of Spironolactone for Hirsutism
The recommended starting dose of spironolactone for hirsutism is 50-100 mg daily, with most evidence supporting 100 mg/day as the optimal starting dose for effectiveness while minimizing side effects. 1
Dosing Considerations
Initial Dosing
- Start with 100 mg/day in the evening 1
- Alternative approach: 50 mg twice daily (100 mg total) on days 4-21 of the menstrual cycle 2, 3
- Lower starting dose of 50 mg daily may be considered for patients concerned about side effects 3, 4
Dose Titration
- Can increase up to 200 mg/day if needed for greater effect 1
- However, side effects increase significantly at higher doses 1, 2
- Several months of treatment are typically required to reach full effectiveness 1
Monitoring Protocol
Initial Monitoring
- Baseline assessment of renal function and serum electrolytes before starting therapy 5
- Follow-up electrolyte checks are not routinely required in young, healthy women without risk factors for hyperkalemia 1
Side Effect Management
- Most common side effect is menstrual irregularities (15-30% of patients) 1
- Side effects are dose-dependent, with significantly higher risk at 200 mg/day 1, 2
- Consider concomitant use of combined oral contraceptives to minimize menstrual irregularities 1
Clinical Evidence
Research has shown varying approaches to dosing:
- In a study of 26 premenopausal women with hirsutism, 68% of those receiving 200 mg/day (100 mg twice daily) required dose reduction due to side effects, primarily menstrual irregularities 2
- A lower dose of 100 mg/day (50 mg twice daily) resulted in significantly fewer side effects 2
- Some studies have shown effectiveness with even lower doses (50-75 mg daily) 3, 4, 6
Important Considerations
- Spironolactone is pregnancy category C and should be avoided during pregnancy 1
- Patients should be counseled about contraception while on spironolactone 1
- Full effect may take several months to become apparent 1, 7
- If side effects occur, consider:
- Reducing the dose
- Changing to cyclic administration (days 4-21 of menstrual cycle)
- Adding a combined oral contraceptive 2
Pitfalls to Avoid
- Starting with too high a dose (200 mg/day) increases risk of side effects without proportional increase in benefit 2
- Failing to counsel patients about the delayed onset of effect (may take 3-6 months for maximal results) 1, 7
- Not discussing potential menstrual irregularities, which are the most common reason for discontinuation 2
- Neglecting to address contraception needs, as spironolactone should be avoided in pregnancy 1
Remember that while higher doses may be more effective, the balance between efficacy and tolerability favors starting at 100 mg/day for most patients with hirsutism.