Drug interactions
Calcium + Gefitinib
Severity: Moderate
Calcium and Gefitinib: 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
Gefitinib absorption depends on an acidic stomach, and raising gastric pH lowers its exposure, as seen with acid-reducing drugs. Antacids such as calcium carbonate may therefore reduce efficacy.
What this interaction means in plain words
Calcium and Gefitinib 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 belongs to Gastrointestinal Tract; Gefitinib belongs to Oncology.
Why it happens
Elevated gastric pH reduces gefitinib solubility and absorption.
What to do
Take the antacid at least 6 hours before or after gefitinib, and avoid long-acting acid suppression where possible.
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
- Calcium + Ceftriaxone Contraindicated
- Acalabrutinib + Calcium Moderate
- Alendronate + Calcium Moderate
- Atazanavir + Calcium Moderate
- Baloxavir marboxil + Calcium Moderate
- Bendroflumethiazide + Calcium Moderate
Other interactions of Gefitinib
Frequently asked questions
Can I take Calcium with Gefitinib?
MediHelp rates the interaction as moderate. Calcium and Gefitinib 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. Gefitinib absorption depends on an acidic stomach, and raising gastric pH lowers its exposure, as seen with acid-reducing drugs. Antacids such as calcium carbonate may therefore reduce efficacy.
How serious is the interaction between Calcium and Gefitinib?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Take the antacid at least 6 hours before or after gefitinib, and avoid long-acting acid suppression where possible.
What other medicines interact with Calcium?
MediHelp also lists interactions of Calcium with, for example, Ceftriaxone, Acalabrutinib, Alendronate. The full list is on the Calcium page.
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