Drug interactions
Methadone + Primaquine
Severity: Moderate
Methadone and Primaquine: 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
Primaquine has been associated with QT prolongation, and methadone also prolongs the QTc interval. The combination may increase the risk of torsades de pointes.
What this interaction means in plain words
Methadone and Primaquine 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; Primaquine belongs to Anti Parasitic.
Why it happens
Additive QT prolongation.
What to do
Check a baseline ECG and electrolytes, and monitor the QTc during the short primaquine course. Avoid other QT-prolonging drugs.
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 Primaquine
- Pimozide + Primaquine Contraindicated
- Amiodarone + Primaquine Major
- Amisulpride + Primaquine Major
- Anagrelide + Primaquine Major
- Arsenic trioxide + Primaquine Major
- Asenapine + Primaquine Major
Frequently asked questions
Can I take Methadone with Primaquine?
MediHelp rates the interaction as moderate. Methadone and Primaquine 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. Primaquine has been associated with QT prolongation, and methadone also prolongs the QTc interval. The combination may increase the risk of torsades de pointes.
How serious is the interaction between Methadone and Primaquine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check a baseline ECG and electrolytes, and monitor the QTc during the short primaquine course. Avoid other QT-prolonging drugs.
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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