Drug interactions
Cimetidine + Posaconazole
Severity: Moderate
Cimetidine and Posaconazole: 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
Cimetidine reduces gastric acidity, which lowers absorption of posaconazole oral suspension and may result in subtherapeutic antifungal levels. Delayed-release tablets are less affected.
What this interaction means in plain words
Cimetidine and Posaconazole 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; Posaconazole belongs to Anti Fungals.
Why it happens
Increased gastric pH reduces dissolution and absorption of posaconazole oral suspension.
What to do
Avoid H2 blockers with posaconazole suspension where possible, or use the delayed-release tablet or IV form. Monitor posaconazole levels and clinical response if the suspension is used.
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 Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
Frequently asked questions
Can I take Cimetidine with Posaconazole?
MediHelp rates the interaction as moderate. Cimetidine and Posaconazole 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 reduces gastric acidity, which lowers absorption of posaconazole oral suspension and may result in subtherapeutic antifungal levels. Delayed-release tablets are less affected.
How serious is the interaction between Cimetidine and Posaconazole?
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 H2 blockers with posaconazole suspension where possible, or use the delayed-release tablet or IV form. Monitor posaconazole levels and clinical response if the suspension is used.
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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