Drug interactions
Calcium carbonate + Hydrochlorothiazide
Severity: Moderate
Calcium carbonate and Hydrochlorothiazide: 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
Thiazides reduce urinary calcium excretion, and with calcium carbonate this can produce hypercalcemia. High doses of absorbable alkali may additionally cause metabolic alkalosis (milk-alkali syndrome).
What this interaction means in plain words
Calcium carbonate and Hydrochlorothiazide 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; Hydrochlorothiazide belongs to Cardiovascular.
Why it happens
Enhanced distal tubular calcium reabsorption by the thiazide adds to calcium load from the supplement.
What to do
Monitor serum calcium and renal function, especially with concurrent vitamin D. Lower the calcium dose if hypercalcemia develops.
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 Hydrochlorothiazide
Frequently asked questions
Can I take Calcium carbonate with Hydrochlorothiazide?
MediHelp rates the interaction as moderate. Calcium carbonate and Hydrochlorothiazide 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. Thiazides reduce urinary calcium excretion, and with calcium carbonate this can produce hypercalcemia. High doses of absorbable alkali may additionally cause metabolic alkalosis (milk-alkali syndrome).
How serious is the interaction between Calcium carbonate and Hydrochlorothiazide?
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, especially with concurrent vitamin D. Lower the calcium dose if hypercalcemia develops.
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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