Drug interactions
Methadone + Quinine
Severity: Major
Methadone and Quinine: major 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 prolong the QT interval, so combination raises the risk of torsades de pointes. Quinine may also inhibit CYP2D6 and CYP3A4, which could modestly affect methadone levels.
What this interaction means in plain words
Methadone and Quinine 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.
Methadone belongs to Musculoskeletal; Quinine belongs to Anti Parasitic.
Why it happens
Additive QT prolongation, with possible CYP inhibition by quinine.
What to do
Avoid if possible; otherwise obtain a baseline ECG and monitor the QTc and electrolytes during treatment. Choose an alternative antimalarial where feasible.
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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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 Quinine
- Arsenic trioxide + Quinine Contraindicated
- Dofetilide + Quinine Contraindicated
- Dronedarone + Quinine Contraindicated
- Ibutilide + Quinine Contraindicated
- Mefloquine + Quinine Contraindicated
- Nilotinib + Quinine Contraindicated
Frequently asked questions
Can I take Methadone with Quinine?
MediHelp rates the interaction as major. Methadone and Quinine 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. Both drugs prolong the QT interval, so combination raises the risk of torsades de pointes. Quinine may also inhibit CYP2D6 and CYP3A4, which could modestly affect methadone levels.
How serious is the interaction between Methadone and Quinine?
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 if possible; otherwise obtain a baseline ECG and monitor the QTc and electrolytes during treatment. Choose an alternative antimalarial where feasible.
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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