Indapamide: Thiazide-Like Diuretic with Vasodilatory Properties
Indapamide is a thiazide-like diuretic (sulfonamide derivative) with direct vasodilatory effects via calcium channel modulation. Its antihypertensive effect is more pronounced than its diuretic effect, making it suitable even at low doses.
Used as first-line hypertension treatment (especially in elderly patients) and is the diuretic used in the ADVANCE trial showing renal and cardiovascular protection in type 2 diabetes.
Mechanism of Action
Indapamide inhibits the Na+/Cl– cotransporter in the distal tubule (like thiazides) and also blocks L-type calcium channels in vascular smooth muscle, providing direct vasodilatation. This dual mechanism results in effective blood pressure lowering with less metabolic disruption than pure thiazides.
Indications & Use
Hypertension (first-line, especially elderly, isolated systolic hypertension, and patients with type 2 diabetes). Often combined with perindopril (ADVANCE trial, fixed-dose Coversyl Plus).
Dosage
Immediate-release: 2.5 mg once daily. Modified-release (SR): 1.5 mg once daily — preferred for better tolerability. Not recommended if GFR <30 mL/min. Monitor electrolytes.
Side Effects
Generally well tolerated. Hypokalaemia, hyponatraemia (milder than HCTZ), hyperuricaemia, mild hyperglycaemia. Skin reactions (photosensitivity). Severe hyponatraemia in elderly.
Drug Interactions
ACE inhibitors: additive antihypertensive effect, first-dose hypotension possible. Lithium: increased toxicity. NSAIDs: reduce diuretic effect. Antiarrhythmics prolonging QT: risk increased by hypokalaemia.
Contraindications
Severe renal impairment (GFR <30), severe hepatic failure, severe hypokalaemia, hypersensitivity to sulfonamide derivatives.
Frequently Asked Questions
How does indapamide compare to HCTZ?
Indapamide has a more favourable metabolic profile (less hyperglycaemia, dyslipidaemia) and direct vasodilatory effects. The modified-release 1.5 mg formulation is well tolerated with effective BP lowering.
Is indapamide effective in type 2 diabetes?
Yes — the ADVANCE trial demonstrated that indapamide combined with perindopril significantly reduced major cardiovascular events and diabetic nephropathy progression in type 2 diabetes.
Can indapamide cause severe sodium loss?
Yes — hyponatraemia is a risk, particularly in elderly women on low-salt diets. Monitor serum sodium at baseline and after dose changes, especially in high-risk patients.
References
- ADVANCE Trial (indapamide+perindopril)
- ESC Hypertension Guidelines 2023
- EMA product information indapamide
Medical Disclaimer: This information is for educational purposes only and does not replace professional medical advice.