Drug interactions
Fluconazole + Trimethoprim
Severity: Minor
Fluconazole and Trimethoprim: minor 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 agents have been linked to QT prolongation, so together they may modestly raise arrhythmia risk, mainly in patients with other risk factors. The evidence is limited.
What this interaction means in plain words
Fluconazole and Trimethoprim have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Fluconazole belongs to Anti Fungals; Trimethoprim belongs to Anti Bacterial.
Why it happens
Possible additive QTc prolongation.
What to do
Check ECG and electrolytes only in patients with additional QT risk factors such as heart disease or other QT-prolonging drugs.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Fluconazole
- Dihydroergotamine intranasal + Fluconazole Contraindicated
- Dihydroergotamine + Fluconazole Contraindicated
- Dofetilide + Fluconazole Contraindicated
- Domperidone + Fluconazole Contraindicated
- Dronedarone + Fluconazole Contraindicated
- Erythromycin + Fluconazole Contraindicated
Other interactions of Trimethoprim
Frequently asked questions
Can I take Fluconazole with Trimethoprim?
MediHelp rates the interaction as minor. Fluconazole and Trimethoprim have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Both agents have been linked to QT prolongation, so together they may modestly raise arrhythmia risk, mainly in patients with other risk factors. The evidence is limited.
How serious is the interaction between Fluconazole and Trimethoprim?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check ECG and electrolytes only in patients with additional QT risk factors such as heart disease or other QT-prolonging drugs.
What other medicines interact with Fluconazole?
MediHelp also lists interactions of Fluconazole with, for example, Dihydroergotamine intranasal, Dihydroergotamine, Dofetilide. The full list is on the Fluconazole page.
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