Drug interactions
Calcium + Ketoconazole
Severity: Moderate
Calcium and Ketoconazole: 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
Ketoconazole needs an acidic stomach to dissolve, so calcium carbonate can reduce its absorption and lead to subtherapeutic antifungal levels. This can cause treatment failure.
What this interaction means in plain words
Calcium and Ketoconazole 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; Ketoconazole belongs to Anti Fungals.
Why it happens
Elevated gastric pH reduces dissolution and absorption of ketoconazole, which is a weak base with pH-dependent solubility.
What to do
Take ketoconazole at least 2 hours before the calcium antacid. Monitor antifungal response, or consider an alternative antifungal.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Calcium and Ketoconazole, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
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 Ketoconazole
- Alfuzosin + Ketoconazole Contraindicated
- Alprazolam + Ketoconazole Contraindicated
- Avanafil + Ketoconazole Contraindicated
- Conivaptan + Ketoconazole Contraindicated
- Dihydroergotamine intranasal + Ketoconazole Contraindicated
- Dihydroergotamine + Ketoconazole Contraindicated
Frequently asked questions
Can I take Calcium with Ketoconazole?
MediHelp rates the interaction as moderate. Calcium and Ketoconazole 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. Ketoconazole needs an acidic stomach to dissolve, so calcium carbonate can reduce its absorption and lead to subtherapeutic antifungal levels. This can cause treatment failure.
How serious is the interaction between Calcium and Ketoconazole?
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 ketoconazole at least 2 hours before the calcium antacid. Monitor antifungal response, or consider an alternative antifungal.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
