Drug interactions
Chlorthalidone + Methyclothiazide
Severity: Moderate
Chlorthalidone and Methyclothiazide: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both drugs are thiazide-type diuretics, so combining them is therapeutically duplicative and increases the risk of hypokalemia, hyponatremia, hypomagnesemia, volume depletion and hyperuricemia without a clear added benefit.
What this interaction means in plain words
Chlorthalidone and Methyclothiazide can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Duplicate inhibition of the sodium-chloride cotransporter in the distal convoluted tubule, causing additive electrolyte loss.
What to do
Avoid combining two thiazide-type diuretics and use a single agent at an appropriate dose. If both have been taken, check electrolytes and renal function.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Chlorthalidone
Frequently asked questions
Can I take Chlorthalidone with Methyclothiazide?
MediHelp rates the interaction as moderate. Chlorthalidone and Methyclothiazide can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both drugs are thiazide-type diuretics, so combining them is therapeutically duplicative and increases the risk of hypokalemia, hyponatremia, hypomagnesemia, volume depletion and hyperuricemia without a clear added benefit.
How serious is the interaction between Chlorthalidone and Methyclothiazide?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid combining two thiazide-type diuretics and use a single agent at an appropriate dose. If both have been taken, check electrolytes and renal function.
What other medicines interact with Chlorthalidone?
MediHelp also lists interactions of Chlorthalidone with, for example, Amifostine, Atenolol-chlorthalidone, Candesartan-hydrochlorothiazide. The full list is on the Chlorthalidone page.
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