Drug interactions
Methadone + Procainamide
Severity: Major
Methadone and Procainamide: major 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
Procainamide is a class Ia antiarrhythmic that prolongs the QT interval and can cause torsades de pointes. Adding methadone, which also lengthens QTc, increases the risk of life-threatening arrhythmia.
What this interaction means in plain words
Methadone and Procainamide can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Additive potassium channel blockade causing delayed ventricular repolarization.
What to do
Avoid concurrent use when an alternative antiarrhythmic or analgesic/opioid maintenance option exists; otherwise monitor ECG for QTc and keep potassium and magnesium normal.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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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
Frequently asked questions
Can I take Methadone with Procainamide?
MediHelp rates the interaction as major. Methadone and Procainamide can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Procainamide is a class Ia antiarrhythmic that prolongs the QT interval and can cause torsades de pointes. Adding methadone, which also lengthens QTc, increases the risk of life-threatening arrhythmia.
How serious is the interaction between Methadone and Procainamide?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid concurrent use when an alternative antiarrhythmic or analgesic/opioid maintenance option exists; otherwise monitor ECG for QTc and keep potassium and magnesium normal.
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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