Drug interactions
Methadone + Venlafaxine
Severity: Moderate
Methadone and Venlafaxine: 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 associated with QT prolongation, and venlafaxine has serotonergic activity that may contribute to serotonin toxicity with methadone. Venlafaxine may also modestly raise methadone exposure. The risk is greatest at high doses or with other risk factors.
What this interaction means in plain words
Methadone and Venlafaxine 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; Venlafaxine belongs to Central Nervous System.
Why it happens
Additive QT prolongation and serotonergic effects, with possible minor CYP2D6 and CYP3A4 effects on methadone clearance.
What to do
Monitor the ECG in patients on higher doses or with cardiac risk factors, and watch for serotonin toxicity symptoms. Adjust methadone dosing based on sedation or withdrawal signs.
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 Venlafaxine
- Isocarboxazid + Venlafaxine Contraindicated
- Methylene blue + Venlafaxine Contraindicated
- Phenelzine + Venlafaxine Contraindicated
- Procarbazine + Venlafaxine Contraindicated
- Rasagiline + Venlafaxine Contraindicated
- Safinamide + Venlafaxine Contraindicated
Frequently asked questions
Can I take Methadone with Venlafaxine?
MediHelp rates the interaction as moderate. Methadone and Venlafaxine 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 associated with QT prolongation, and venlafaxine has serotonergic activity that may contribute to serotonin toxicity with methadone. Venlafaxine may also modestly raise methadone exposure. The risk is greatest at high doses or with other risk factors.
How serious is the interaction between Methadone and Venlafaxine?
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 on higher doses or with cardiac risk factors, and watch for serotonin toxicity symptoms. Adjust methadone dosing based on sedation or withdrawal signs.
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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