Drug interactions
Methadone + Trimethoprim
Severity: Moderate
Methadone 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
Trimethoprim has been associated with QT prolongation in some reports, and methadone is a well-known QT-prolonging drug. Combined use may add to the arrhythmia risk, mainly in patients with other risk factors.
What this interaction means in plain words
Methadone 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.
Methadone belongs to Musculoskeletal; Trimethoprim belongs to Anti Bacterial.
Why it happens
Possible additive QT prolongation; the trimethoprim contribution is weak and not well established.
What to do
Monitor the ECG in patients with additional risk factors such as high methadone doses or low potassium or magnesium. Correct electrolytes before treatment.
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 Methadone
- Alvimopan + Methadone Contraindicated
- Calcium / magnesium / potassium / sodium oxybates + Methadone Contraindicated
- Droperidol + Methadone Contraindicated
- Ibutilide + Methadone Contraindicated
- Isocarboxazid + Methadone Contraindicated
- Lefamulin + Methadone Contraindicated
Other interactions of Trimethoprim
Frequently asked questions
Can I take Methadone with Trimethoprim?
MediHelp rates the interaction as moderate. Methadone 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. Trimethoprim has been associated with QT prolongation in some reports, and methadone is a well-known QT-prolonging drug. Combined use may add to the arrhythmia risk, mainly in patients with other risk factors.
How serious is the interaction between Methadone 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: Monitor the ECG in patients with additional risk factors such as high methadone doses or low potassium or magnesium. Correct electrolytes before treatment.
What other medicines interact with Methadone?
MediHelp also lists interactions of Methadone with, for example, Alvimopan, Calcium / magnesium / potassium / sodium oxybates, Droperidol. The full list is on the Methadone page.
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