Drug interactions
Calcium carbonate + Tetracycline
Severity: Moderate
Calcium carbonate and Tetracycline: 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
Calcium carbonate substantially reduces tetracycline absorption, which may lead to treatment failure.
What this interaction means in plain words
Calcium carbonate and Tetracycline 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; Tetracycline belongs to Anti Bacterial.
Why it happens
Calcium ions chelate tetracycline in the gut, forming insoluble, poorly absorbed complexes.
What to do
Give tetracycline at least 2 hours before or 4 hours after calcium carbonate.
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 Tetracycline
- Acitretin + Tetracycline Contraindicated
- Methoxyflurane + Tetracycline Contraindicated
- Isotretinoin + Tetracycline Major
- Palovarotene + Tetracycline Major
- Strontium ranelate + Tetracycline Major
- Tetracycline + Tretinoin Major
Frequently asked questions
Can I take Calcium carbonate with Tetracycline?
MediHelp rates the interaction as moderate. Calcium carbonate and Tetracycline 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 substantially reduces tetracycline absorption, which may lead to treatment failure.
How serious is the interaction between Calcium carbonate and Tetracycline?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Give tetracycline at least 2 hours before or 4 hours after calcium carbonate.
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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