Drug interactions
Conivaptan + Methadone
Severity: Moderate
Conivaptan 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
Conivaptan is a CYP3A4 inhibitor and may raise methadone concentrations, increasing sedation, respiratory depression and QT risk. It is used short term, which limits the exposure window.
What this interaction means in plain words
Conivaptan 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.
Why it happens
Inhibition of CYP3A4-mediated methadone metabolism.
What to do
Monitor for sedation, respiratory depression and QTc prolongation during and shortly after conivaptan infusion. Reduce the methadone dose if signs of excess opioid effect appear.
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
Frequently asked questions
Can I take Conivaptan with Methadone?
MediHelp rates the interaction as moderate. Conivaptan 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. Conivaptan is a CYP3A4 inhibitor and may raise methadone concentrations, increasing sedation, respiratory depression and QT risk. It is used short term, which limits the exposure window.
How serious is the interaction between Conivaptan 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: Monitor for sedation, respiratory depression and QTc prolongation during and shortly after conivaptan infusion. Reduce the methadone dose if signs of excess opioid effect appear.
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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