How it works
Spironolactone competitively blocks aldosterone at mineralocorticoid receptors and competitively binds the androgen receptor. The androgen blockade is responsible for its dermatologic and PCOS uses.
The evidence
Long-standing off-label dermatologic use for adult female acne, with multiple cohort studies supporting efficacy at 50–200 mg daily. Topical formulations show similar efficacy on hormonal acne with substantially fewer systemic side effects.
Typical dosing
Oral: 50–100 mg daily, titratable to 200 mg. Topical: typically 5% formulation applied once daily.
Side effects
Common
- Increased urination (oral)
- Menstrual irregularity (oral)
- Breast tenderness (oral)
Less common
- Hyperkalemia (oral)
- Dizziness
Rare
- Severe hyperkalemia in renal impairment
Drug interactions
- ACE inhibitors / ARBs — hyperkalemia risk
- Potassium supplements — hyperkalemia risk
- NSAIDs — reduced efficacy and renal stress