Drug interactions
Calcium carbonate + Chlorthalidone
Severity: Moderate
Calcium carbonate and Chlorthalidone: 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
Thiazide-like diuretics reduce urinary calcium excretion, and calcium carbonate adds a calcium load. Together they can cause hypercalcemia and, with large doses of absorbable alkali, metabolic alkalosis (milk-alkali syndrome).
What this interaction means in plain words
Calcium carbonate and Chlorthalidone 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.
Calcium carbonate belongs to Gastrointestinal Tract; Chlorthalidone belongs to Cardiovascular.
Why it happens
Enhanced distal tubular calcium reabsorption by the diuretic adds to calcium intake from the supplement.
What to do
Monitor serum calcium and renal function, particularly with high-dose calcium or vitamin D. Reduce calcium dose if hypercalcemia occurs.
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 Calcium carbonate
Other interactions of Chlorthalidone
Frequently asked questions
Can I take Calcium carbonate with Chlorthalidone?
MediHelp rates the interaction as moderate. Calcium carbonate and Chlorthalidone 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. Thiazide-like diuretics reduce urinary calcium excretion, and calcium carbonate adds a calcium load. Together they can cause hypercalcemia and, with large doses of absorbable alkali, metabolic alkalosis (milk-alkali syndrome).
How serious is the interaction between Calcium carbonate and Chlorthalidone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor serum calcium and renal function, particularly with high-dose calcium or vitamin D. Reduce calcium dose if hypercalcemia occurs.
What other medicines interact with Calcium carbonate?
MediHelp also lists interactions of Calcium carbonate with, for example, Acalabrutinib, Alendronate, Amlodipine-hydrochlorothiazide-valsartan. The full list is on the Calcium carbonate page.
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