Drug interactions
Methadone + Salmeterol
Severity: Moderate
Methadone and Salmeterol: 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
Methadone prolongs the QT interval and salmeterol, a long-acting beta-2 agonist, can cause tachycardia, hypokalemia and QT prolongation, especially at higher doses. Together they may raise the risk of arrhythmia, including torsades de pointes, in predisposed patients.
What this interaction means in plain words
Methadone and Salmeterol 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; Salmeterol belongs to Respiratory.
Why it happens
Additive QT prolongation, with beta-2 agonist induced hypokalemia further increasing arrhythmia risk.
What to do
Monitor ECG and serum potassium and magnesium in patients on methadone who start salmeterol, particularly with other QT-prolonging drugs or cardiac disease.
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 Salmeterol
- Ritonavir + Salmeterol Contraindicated
- Salmeterol + Saquinavir Contraindicated
- Amitriptyline + Salmeterol Major
- Arformoterol + Salmeterol Major
- Atazanavir + Salmeterol Major
- Budesonide-formoterol + Salmeterol Major
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 Salmeterol?
MediHelp rates the interaction as moderate. Methadone and Salmeterol 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 prolongs the QT interval and salmeterol, a long-acting beta-2 agonist, can cause tachycardia, hypokalemia and QT prolongation, especially at higher doses. Together they may raise the risk of arrhythmia, including torsades de pointes, in predisposed patients.
How serious is the interaction between Methadone and Salmeterol?
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 ECG and serum potassium and magnesium in patients on methadone who start salmeterol, particularly with other QT-prolonging drugs or cardiac disease.
What other medicines interact with Salmeterol?
MediHelp also lists interactions of Salmeterol with, for example, Ritonavir, Saquinavir, Amitriptyline. The full list is on the Salmeterol page.
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