Spironolactone

Spironolactone is a potassium-sparing diuretic and aldosterone antagonist with diverse clinical uses. It is prescribed for resistant hypertension, heart failure, liver cirrhosis with ascites, and primary hyperaldosteronism (Conn's syndrome). Due to its anti-androgenic properties, it is also used off-label for the treatment of female-pattern hair loss, hormonal acne, and hirsutism.

In heart failure, spironolactone has been shown in the RALES trial to reduce mortality significantly when added to standard therapy at low doses.

How to Take Spironolactone

Take spironolactone once daily, usually in the morning with food. Taking it with a meal improves absorption and reduces the chance of stomach upset. The dose depends on the condition being treated; for fluid retention or heart failure it typically ranges from 25 mg to 100 mg daily, while for hormonal conditions like acne or hirsutism lower doses of 25 mg to 50 mg are common.

Monitoring During Treatment

Your doctor will want to check your potassium levels and kidney function with regular blood tests, especially when starting treatment or changing the dose. Let your doctor know straight away if you notice muscle weakness, an irregular heartbeat, or feeling unusually dizzy.

For heart failure: 25 mg once daily, which may be increased to 50 mg if tolerated. For resistant hypertension: 25 mg to 50 mg daily. For liver cirrhosis: 100 mg to 400 mg daily. For anti-androgenic effects: 50 mg to 200 mg daily. Dose adjustments are needed based on potassium levels and renal function.

Common Side Effects

Common side effects include:

• Raised potassium (hyperkalaemia), the most important risk, requiring regular monitoring
• Breast tenderness or breast tissue growth in men (gynaecomastia)
• Irregular or missed periods
• Dizziness
• Stomach discomfort

High potassium is the most clinically important concern with spironolactone, especially in people with kidney problems or those taking ACE inhibitors or ARBs. Symptoms include muscle weakness, fatigue, and heart palpitations. Seek medical attention if you notice an irregular heartbeat or severe muscle weakness.

Monitor potassium and renal function regularly. Avoid potassium supplements and potassium-rich salt substitutes. Spironolactone should not be used in pregnancy due to its anti-androgenic effects on a developing male foetus.

Contraindicated in Addison's disease, hyperkalaemia, severe renal impairment, anuria, and known hypersensitivity to spironolactone.