Home›Drug Doses›Spironolactone
⚠️Monitor potassium — spironolactone causes K⁺ retention. Contraindicated in K⁺ >5.0 mmol/L, severe CKD (eGFR <30), and Addison's disease. Avoid K⁺ supplements and concurrent ACEi/ARB at high doses.
💊 Potassium-sparing diuretic · Aldosterone antagonist · HF · Ascites · PCOS

Spironolactone Dose Calculator

India · Heart Failure · Liver Ascites · Hypertension · PCOS · Hyperaldosteronism · Aldactone · Spiromide · Spiro

HF: 25–50 mg ODAscites: 100–400 mgPCOS: 50–200 mgMonitor K⁺ + eGFR

Spironolactone Dose Calculator

Spironolactone Dose
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Tablet
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Max dose
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K⁺ check
1 week, 1 month, then 3-monthly
eGFR check
1 week after start and each dose change
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💊 Drug profile
ClassMineralocorticoid antagonist
RouteOral only
Onset2–3 days (full effect 7–14 days)
Half-life1.4h (active metabolites 16–23h)
Hepatic metabolismExtensive — active metabolites
Main ADRHyperkalaemia · Gynaecomastia
🏷️ Indian brands
25 mg tabletAldactone 25 · Spiromide 25 · Spiro
50 mg tabletAldactone 50 · Spiromide 50
100 mg tabletAldactone 100 · Spiromide 100
+ FurosemideLasoride · Aldoril · Frusamide-S
🚫 Contraindications

✗ K⁺ > 5.0 mmol/L before starting

✗ eGFR < 30 mL/min (risk of severe hyperkalaemia)

✗ Addison's disease

⚠️ Use cautiously with ACEi/ARB + spironolactone (triple K⁺ rise risk)

⚠️ Gynaecomastia in men — dose-dependent; consider eplerenone

⚠️ Menstrual irregularities — common in women at high doses

Spironolactone — Clinical Guide India

Spironolactone (Aldactone, Spiromide) is an aldosterone antagonist and potassium-sparing diuretic with proven mortality benefit in heart failure (RALES trial), essential role in cirrhotic ascites management, and expanding use in PCOS and resistant hypertension. Its mechanism — blocking mineralocorticoid receptors in the collecting duct — prevents aldosterone-driven sodium retention and potassium excretion, making it the ideal complement to loop diuretics (furosemide) which cause significant potassium loss. The main risks are hyperkalaemia (particularly dangerous in CKD and when combined with ACE inhibitors or ARBs) and anti-androgenic side effects (gynaecomastia in men, menstrual irregularities in women).

Heart failure — the RALES trial impact

The landmark RALES trial (1999) demonstrated that adding low-dose spironolactone (25 mg daily, increased to 50 mg if tolerated) to standard HF therapy (ACE inhibitor + loop diuretic) reduced mortality by 30% in severe HFrEF. This established spironolactone as a mandatory part of HFrEF pharmacotherapy alongside ACE inhibitors/ARBs, beta-blockers, and loop diuretics. The key teaching from RALES: the dose for HF is 25–50 mg — much lower than the 100–400 mg used for ascites. Using ascites doses in HF causes severe hyperkalaemia, especially when combined with ACE inhibitors. ESC guidelines now recommend mineralocorticoid antagonists (spironolactone or eplerenone) for all patients with HFrEF and LVEF ≤35% who remain symptomatic despite ACE inhibitor + beta-blocker.

Cirrhotic ascites — the 100:40 ratio with furosemide

In liver cirrhosis with ascites, spironolactone is the primary diuretic (targeting aldosterone excess from portal hypertension-driven renin-angiotensin-aldosterone activation). Furosemide is added as a second agent. The classic combination ratio is spironolactone:furosemide = 100:40 mg — this maintains electrolyte balance. Starting dose: spironolactone 100 mg + furosemide 40 mg daily. Titrate upward maintaining the same ratio: 150 mg:60 mg → 200 mg:80 mg → maximum 400 mg:160 mg. Target weight loss: 0.5 kg/day (maximum 1 kg/day if peripheral oedema is also present). The combination Lasoride tablet (spironolactone 50 mg + furosemide 20 mg) is widely available in India and convenient for ascites management.

PCOS — anti-androgenic use

Spironolactone 50–200 mg daily is used off-label in India for PCOS-related hirsutism, acne, and androgenic alopecia. It blocks androgen receptors and reduces adrenal and ovarian androgen synthesis. Most benefit is seen at 100–200 mg/day. Onset is slow — 3–6 months for significant hirsutism improvement. Effective contraception is mandatory in women of childbearing age taking spironolactone — it can cause feminisation of a male fetus. It is often combined with oral contraceptive pills in India for PCOS management (OCP also reduces androgen production and provides contraception).

Frequently Asked Questions

When should spironolactone be started and what K⁺ level is safe?+
Spironolactone should only be started when: serum K⁺ is ≤5.0 mmol/L AND eGFR is ≥30 mL/min (RALES criteria, ESC guidelines). Check K⁺ and eGFR at baseline, 1 week after starting, 1 month, and then every 3 months when stable. If K⁺ rises above 5.5 mmol/L: halve the dose and recheck in 1 week. If K⁺ exceeds 6.0 mmol/L: stop spironolactone immediately and review all other potassium-retaining medications.
What is the difference between spironolactone and eplerenone?+
Both are mineralocorticoid antagonists with similar cardiac benefit (EPHESUS trial for eplerenone post-MI). Key difference: eplerenone is selective for mineralocorticoid receptors and lacks anti-androgenic and anti-progestogenic activity. This means eplerenone does not cause gynaecomastia in men or menstrual irregularities in women — important when these side effects limit spironolactone use. Eplerenone is more expensive and not yet as widely available in India as spironolactone. Typical dose: eplerenone 25 mg OD → 50 mg OD for HFrEF. Consider switching from spironolactone to eplerenone in men with troublesome gynaecomastia.
⚠️Check K⁺ and eGFR before starting and 1 week after. Do not start if K⁺ >5.0 or eGFR <30. For HF use 25–50mg only — not ascites doses. Mandatory contraception in women of childbearing potential. Verify against BNF and ESC HF guidelines.

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