Drug interactions
Citalopram + Methadone
Severity: Major
Citalopram and Methadone: 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
Citalopram causes dose-dependent QT prolongation that adds to the effect of methadone, increasing the risk of torsades de pointes. Both drugs also have serotonergic activity, so serotonin syndrome is a possible concern.
What this interaction means in plain words
Citalopram and Methadone 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.
Citalopram belongs to Central Nervous System; Methadone belongs to Musculoskeletal.
Why it happens
Additive QT prolongation, plus additive serotonergic effects and possible CYP2D6/CYP2C19-mediated pharmacokinetic effects.
What to do
Obtain a baseline ECG and monitor the QTc, keeping citalopram within recommended maximum doses and correcting electrolytes. Consider an alternative antidepressant such as sertraline and watch for serotonin toxicity.
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
Other interactions of Citalopram
- Cisapride + Citalopram Contraindicated
- Citalopram + Dronedarone Contraindicated
- Citalopram + Escitalopram Contraindicated
- Citalopram + Isocarboxazid Contraindicated
- Citalopram + Methylene blue Contraindicated
- Citalopram + Phenelzine Contraindicated
Frequently asked questions
Can I take Citalopram with Methadone?
MediHelp rates the interaction as major. Citalopram and Methadone 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. Citalopram causes dose-dependent QT prolongation that adds to the effect of methadone, increasing the risk of torsades de pointes. Both drugs also have serotonergic activity, so serotonin syndrome is a possible concern.
How serious is the interaction between Citalopram and Methadone?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain a baseline ECG and monitor the QTc, keeping citalopram within recommended maximum doses and correcting electrolytes. Consider an alternative antidepressant such as sertraline and watch for serotonin toxicity.
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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