Drug interactions
Methadone + Pimozide
Severity: Contraindicated
Methadone and Pimozide: contraindicated interaction.
Last updated Sources: US FDA label
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 prolong the QT interval, and pimozide carries a notable risk of torsades de pointes. Combined use may cause life-threatening ventricular arrhythmias.
What this interaction means in plain words
Methadone and Pimozide are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Methadone belongs to Musculoskeletal; Pimozide belongs to Central Nervous System.
Why it happens
Additive QT prolongation through cardiac potassium channel blockade, and methadone may inhibit CYP2D6 metabolism of pimozide.
What to do
Avoid the combination and choose an alternative antipsychotic with less QT effect. Where unavoidable, require ECG monitoring in a specialist setting.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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References
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 Pimozide
- Adagrasib + Pimozide Contraindicated
- Amiodarone + Pimozide Contraindicated
- Amisulpride + Pimozide Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amoxapine + Pimozide Contraindicated
- Anagrelide + Pimozide Contraindicated
Frequently asked questions
Can I take Methadone with Pimozide?
MediHelp rates the interaction as contraindicated. Methadone and Pimozide are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Both drugs prolong the QT interval, and pimozide carries a notable risk of torsades de pointes. Combined use may cause life-threatening ventricular arrhythmias.
How serious is the interaction between Methadone and Pimozide?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination and choose an alternative antipsychotic with less QT effect. Where unavoidable, require ECG monitoring in a specialist setting.
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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