Drug interactions
Calcium carbonate + Isoniazid
Severity: Minor
Calcium carbonate and Isoniazid: minor 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
Antacids, mainly aluminium-containing ones, can reduce isoniazid absorption. Calcium carbonate has less documented effect, but lower levels could risk reduced efficacy.
What this interaction means in plain words
Calcium carbonate and Isoniazid have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Calcium carbonate belongs to Gastrointestinal Tract; Isoniazid belongs to Anti Bacterial.
Why it happens
Possible reduced gastrointestinal absorption of isoniazid in the presence of antacids.
What to do
Give isoniazid on an empty stomach at least 1 to 2 hours before the calcium antacid.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Calcium carbonate
Other interactions of Isoniazid
Frequently asked questions
Can I take Calcium carbonate with Isoniazid?
MediHelp rates the interaction as minor. Calcium carbonate and Isoniazid have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Antacids, mainly aluminium-containing ones, can reduce isoniazid absorption. Calcium carbonate has less documented effect, but lower levels could risk reduced efficacy.
How serious is the interaction between Calcium carbonate and Isoniazid?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Give isoniazid on an empty stomach at least 1 to 2 hours before the calcium antacid.
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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