Drug interactions
Isoflurane + Methadone
Severity: Moderate
Isoflurane and Methadone: 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
Isoflurane can prolong the QT interval and methadone does so as well, adding to arrhythmia risk during anesthesia. Opioids and volatile anesthetics also add to cardiorespiratory depression.
What this interaction means in plain words
Isoflurane and Methadone 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.
Isoflurane belongs to Central Nervous System; Methadone belongs to Musculoskeletal.
Why it happens
Additive QT prolongation and additive CNS and cardiovascular depression.
What to do
Tell the anesthesia team about methadone use, check the preoperative ECG and electrolytes, and monitor the ECG during and after anesthesia. Avoid other QT-prolonging drugs perioperatively.
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 Isoflurane
Frequently asked questions
Can I take Isoflurane with Methadone?
MediHelp rates the interaction as moderate. Isoflurane and Methadone 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. Isoflurane can prolong the QT interval and methadone does so as well, adding to arrhythmia risk during anesthesia. Opioids and volatile anesthetics also add to cardiorespiratory depression.
How serious is the interaction between Isoflurane and Methadone?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Tell the anesthesia team about methadone use, check the preoperative ECG and electrolytes, and monitor the ECG during and after anesthesia. Avoid other QT-prolonging drugs perioperatively.
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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