Drug interactions
Posaconazole + Trimethoprim
Severity: Moderate
Posaconazole and Trimethoprim: 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
Both drugs have been linked to QT prolongation, so the combination may add to arrhythmia risk. The evidence for trimethoprim alone is limited, and the risk is mainly relevant in patients with other risk factors.
What this interaction means in plain words
Posaconazole and Trimethoprim 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.
Posaconazole belongs to Anti Fungals; Trimethoprim belongs to Anti Bacterial.
Why it happens
Possible additive effects on cardiac repolarization; the trimethoprim contribution is poorly established.
What to do
Check baseline QTc and correct hypokalemia and hypomagnesemia. Monitor ECG in patients with cardiac disease or other QT-prolonging drugs.
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 Posaconazole
- Artemether + Posaconazole Contraindicated
- Avanafil + Posaconazole Contraindicated
- Cobimetinib + Posaconazole Contraindicated
- Conivaptan + Posaconazole Contraindicated
- Dihydroergotamine intranasal + Posaconazole Contraindicated
- Dihydroergotamine + Posaconazole Contraindicated
Other interactions of Trimethoprim
Frequently asked questions
Can I take Posaconazole with Trimethoprim?
MediHelp rates the interaction as moderate. Posaconazole and Trimethoprim 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. Both drugs have been linked to QT prolongation, so the combination may add to arrhythmia risk. The evidence for trimethoprim alone is limited, and the risk is mainly relevant in patients with other risk factors.
How serious is the interaction between Posaconazole and Trimethoprim?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check baseline QTc and correct hypokalemia and hypomagnesemia. Monitor ECG in patients with cardiac disease or other QT-prolonging drugs.
What other medicines interact with Posaconazole?
MediHelp also lists interactions of Posaconazole with, for example, Artemether, Avanafil, Cobimetinib. The full list is on the Posaconazole page.
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