Drug interactions
Capecitabine + Methadone
Severity: Moderate
Capecitabine and Methadone: 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
Methadone prolongs the QT interval in a dose-dependent manner. Capecitabine has been associated with QT prolongation and rare arrhythmias, so combined use may add to the risk of torsades de pointes, especially with electrolyte disturbance or heart disease.
What this interaction means in plain words
Capecitabine and Methadone 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.
Capecitabine belongs to Oncology; Methadone belongs to Musculoskeletal.
Why it happens
Additive effects on cardiac repolarization; capecitabine's QT effect is less well characterized.
What to do
Obtain a baseline ECG and monitor the QTc during combined therapy. Correct potassium and magnesium abnormalities and avoid other QT-prolonging drugs where possible.
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 Capecitabine
Frequently asked questions
Can I take Capecitabine with Methadone?
MediHelp rates the interaction as moderate. Capecitabine and Methadone 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 prolongs the QT interval in a dose-dependent manner. Capecitabine has been associated with QT prolongation and rare arrhythmias, so combined use may add to the risk of torsades de pointes, especially with electrolyte disturbance or heart disease.
How serious is the interaction between Capecitabine and Methadone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain a baseline ECG and monitor the QTc during combined therapy. Correct potassium and magnesium abnormalities and avoid other QT-prolonging drugs where possible.
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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