Drug interactions
Citalopram + Clozapine
Severity: Major
Citalopram and Clozapine: major interaction.
Last updated Sources: UK SmPC
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 QT interval, and clozapine also carries risks of myocarditis and orthostasis. Combined use raises the potential for arrhythmia, and citalopram may modestly increase clozapine levels.
What this interaction means in plain words
Citalopram and Clozapine 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; Clozapine belongs to Central Nervous System.
Why it happens
Additive QT prolongation, with possible minor CYP-mediated increases in clozapine concentration.
What to do
Obtain a baseline ECG and monitor electrolytes, and repeat the ECG after dose changes. Watch for clozapine adverse effects and consider levels if toxicity is suspected.
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 Citalopram
- Cisapride + Citalopram Contraindicated
- Citalopram + Dronedarone Contraindicated
- Citalopram + Escitalopram Contraindicated
- Citalopram + Isocarboxazid Contraindicated
- Citalopram + Methylene blue Contraindicated
- Citalopram + Phenelzine Contraindicated
Other interactions of Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Frequently asked questions
Can I take Citalopram with Clozapine?
MediHelp rates the interaction as major. Citalopram and Clozapine 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 QT interval, and clozapine also carries risks of myocarditis and orthostasis. Combined use raises the potential for arrhythmia, and citalopram may modestly increase clozapine levels.
How serious is the interaction between Citalopram and Clozapine?
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 electrolytes, and repeat the ECG after dose changes. Watch for clozapine adverse effects and consider levels if toxicity is suspected.
What other medicines interact with Citalopram?
MediHelp also lists interactions of Citalopram with, for example, Cisapride, Dronedarone, Escitalopram. The full list is on the Citalopram page.
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