From the Guidelines
The equivalent dose of indapamide to chlorthalidone 12.5 mg is approximately 1.25 mg of indapamide. When switching between these thiazide-like diuretics, this conversion is appropriate for most patients requiring similar antihypertensive effects. Indapamide is typically available in 1.25 mg and 2.5 mg tablets, with the 1.25 mg dose being the closest equivalent to chlorthalidone 12.5 mg. Both medications work similarly by inhibiting sodium and chloride reabsorption in the distal tubule of the kidney, but they have different potencies and durations of action. Chlorthalidone has a longer half-life (approximately 40-60 hours) compared to indapamide (approximately 14-18 hours), which may affect dosing frequency. When making this switch, monitor blood pressure and electrolytes, particularly potassium levels, as both medications can cause hypokalemia, as noted in the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1. Patients should take indapamide in the morning to avoid nighttime urination and should be advised that full antihypertensive effects may take several weeks to develop.
Some key points to consider when making this switch include:
- Monitoring for hyponatremia and hypokalemia, uric acid and calcium levels, as chlorthalidone is preferred on the basis of prolonged half-life and proven trial reduction of CVD 1
- Using indapamide with caution in patients with history of acute gout unless patient is on uric acid–lowering therapy 1
- Being aware of the potential for increased risk of hyperkalemia, especially in patients with CKD or in those on K+ supplements or K-sparing drugs, when using other antihypertensive medications in combination with indapamide or chlorthalidone 1
- Considering the use of loop diuretics in patients with CKD, as they are preferred over thiazides in patients with moderate-to-severe CKD (eg, GFR <30 mL/min) 1
From the Research
Indapamide Equivalent Dose to Chlorthalidone 12.5mg
- The equivalent dose of indapamide to chlorthalidone 12.5mg is not directly stated in the provided studies.
- However, a study from 1975 2 compared the hypotensive activity of 5mg indapamide daily with 100mg chlorthalidone daily, suggesting that indapamide may be more potent than chlorthalidone.
- Another study from 2016 3 mentioned that hydrochlorothiazide (HCTZ) is 4.2-6.2 systolic mm Hg less potent than chlorthalidone (CTDN), and HCTZ is also less potent than indapamide (INDAP) by office measurements.
- It is worth noting that the potency and efficacy of different diuretics can vary, and the choice of diuretic may depend on individual patient factors and clinical guidelines 4, 5, 6.
- In terms of safety and tolerability, indapamide and chlorthalidone have been shown to have favorable profiles, with indapamide being associated with a lesser rate of hypokalemia and abnormalities of metabolic profile 6.