Drug interactions
Methadone + Trifluoperazine
Severity: Major
Methadone and Trifluoperazine: major interaction.
Last updated Sources: US FDA label
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 can prolong the QTc interval, raising the risk of torsades de pointes, and both cause sedation. Additive CNS and respiratory depression may also occur.
What this interaction means in plain words
Methadone and Trifluoperazine 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.
Why it happens
Additive hERG-channel QT prolongation and additive CNS depression.
What to do
Check baseline and follow-up ECGs and keep potassium and magnesium normal. Monitor for sedation and reduce doses if the QTc lengthens.
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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References
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 Trifluoperazine?
MediHelp rates the interaction as major. Methadone and Trifluoperazine 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 can prolong the QTc interval, raising the risk of torsades de pointes, and both cause sedation. Additive CNS and respiratory depression may also occur.
How serious is the interaction between Methadone and Trifluoperazine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check baseline and follow-up ECGs and keep potassium and magnesium normal. Monitor for sedation and reduce doses if the QTc lengthens.
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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