Drug interactions
Cimetidine + Itraconazole
Severity: Moderate
Cimetidine and Itraconazole: 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
Itraconazole capsules need gastric acid for dissolution, so cimetidine can lower their absorption and reduce antifungal exposure. This may lead to treatment failure in serious fungal infections.
What this interaction means in plain words
Cimetidine and Itraconazole 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.
Cimetidine belongs to Gastrointestinal Tract; Itraconazole belongs to Anti Fungals.
Why it happens
Increased gastric pH reduces dissolution and absorption of itraconazole capsules.
What to do
Avoid acid suppressants with itraconazole capsules where possible, or give the capsules with an acidic beverage such as cola; alternatively use the oral solution or SUBA formulation, and consider monitoring itraconazole levels.
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 Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram Major
Other interactions of Itraconazole
- Alfuzosin + Itraconazole Contraindicated
- Alprazolam + Itraconazole Contraindicated
- Avanafil + Itraconazole Contraindicated
- Conivaptan + Itraconazole Contraindicated
- Dihydroergotamine intranasal + Itraconazole Contraindicated
- Dihydroergotamine + Itraconazole Contraindicated
Frequently asked questions
Can I take Cimetidine with Itraconazole?
MediHelp rates the interaction as moderate. Cimetidine and Itraconazole 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. Itraconazole capsules need gastric acid for dissolution, so cimetidine can lower their absorption and reduce antifungal exposure. This may lead to treatment failure in serious fungal infections.
How serious is the interaction between Cimetidine and Itraconazole?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid acid suppressants with itraconazole capsules where possible, or give the capsules with an acidic beverage such as cola; alternatively use the oral solution or SUBA formulation, and consider monitoring itraconazole levels.
What other medicines interact with Cimetidine?
MediHelp also lists interactions of Cimetidine with, for example, Dofetilide, Fezolinetant, Alfentanil. The full list is on the Cimetidine page.
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