Spironolactone
ALDACTONE
Pronunciation: spir-on-oe-LAK-toen
“Ald(osterone) redactor’s Spiral lactose cone”
Weak anti-androgen → possible gynecomastia
Bananas in bunches → ↑ serum potassium
What it isMineralocorticoid-receptor antagonist; heart failure, resistant hypertension, ascites, acne and hirsutism.
Why this oneUnlike eplerenone, its antiandrogen activity makes it useful for acne and hirsutism — and causes gynecomastia.
What limits itHyperkalemia and renal decline are limiting; check potassium and creatinine after initiation and dose changes.
Pearls
- Avoid in pregnancy: can feminize a male fetus.
- Menstrual irregularity and breast tenderness are common in women.
- Heart failure: avoid starting if K >5.0 mEq/L or eGFR ≤30.
Spironolactone prescription history
Animated chart of estimated U.S. prescriptions per year, Diuretics (1953–2026). Spironolactone enters in 1960 (estimated).
FDA-approved for
- heart failure/edema (1960)
Off-label
- acne
- female-pattern hair loss
- hirsutism
Principal riskHyperkalemia
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityHyperkalemia, kidney dysfunction and endocrine adverse effects.
FDA label
Read the full label on DailyMed ↗
NO BOXED WARNINGS
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Heart failure | Adults (K+ ≤5.0, eGFR >50) | 25 mg QD | 50 mg QD | |
| Essential hypertension | Adults | 25-100 mg/day (QD or divided) | 25-100 mg/day | 100 mg/day |
| Edema (incl. cirrhosis) | Adults | 100 mg/day (QD or divided; range 25-200) | 25-200 mg/day | |
| Primary hyperaldosteronism | Adults | 100-400 mg/day | lowest effective dose |
Titration HTN: titrate at 2-week intervals; edema (sole diuretic): wait ≥5 days before increasing.
Renal HF with eGFR 30-50 mL/min/1.73m²: consider 25 mg every other day (hyperkalemia risk).
Hepatic Cirrhosis/edema: initiate in hospital and titrate slowly; risk of impaired neurologic function/coma.
HF: reduce to 25 mg every other day if hyperkalemia develops.
Instructions
- Take with or without food, but consistently with respect to food.
Available strengths
- tab 25, 50, 100 mg
- susp 25 mg/5 mL
Contraindications
- Hyperkalemia
- Addison's disease
- Concomitant use of eplerenone
Cautions
- Hyperkalemia — monitor serum K+ within 1 week of initiation/titration then regularly
- Hypotension and worsening renal function — monitor volume status/renal function
- Electrolyte and metabolic abnormalities (hyponatremia, hyperglycemia, hyperuricemia)
- Gynecomastia (dose- and duration-dependent, usually reversible)
Adverse reactions
- Gynecomastia (most common)
- GI: gastric bleeding/ulceration, nausea, vomiting, cramping, diarrhea
- Hyperkalemia and electrolyte disturbances
- Leukopenia (incl. agranulocytosis), thrombocytopenia
- SJS/TEN/DRESS
- Renal dysfunction/failure
Pregnancy Avoid; anti-androgenic activity may affect male fetal sex differentiation (animal data).
Lactation Metabolite canrenone present in milk in low, likely inconsequential amounts; weigh benefits/risks.
Cost
Generic entry1982
Open Spironolactone in the interactive console ↗
Memory aids: interaction avatars
Open Spironolactone in the interactive console ↗
Self-check
- What distinguishes spironolactone from eplerenone for acne?
Antiandrogen activity. - What should be checked after spironolactone initiation or dose changes?
Potassium and creatinine.