Drug interactions
Citalopram + Lapatinib
Severity: Major
Citalopram and Lapatinib: major interaction.
Last updated Sources: Health Canada product monograph
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, so combining them has an additive effect on cardiac repolarization. This raises the risk of torsades de pointes, especially with electrolyte disturbances, bradycardia or heart disease.
What this interaction means in plain words
Citalopram and Lapatinib 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; Lapatinib belongs to Oncology.
Why it happens
Additive pharmacodynamic QT prolongation through delayed cardiac repolarization (hERG potassium channel effects).
What to do
Obtain a baseline ECG and repeat after initiation, and correct hypokalemia and hypomagnesemia. Consider an alternative antidepressant if the QTc becomes prolonged.
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 Lapatinib
- Dofetilide + Lapatinib Contraindicated
- Ibutilide + Lapatinib Contraindicated
- Lapatinib + Pimozide Contraindicated
- Lapatinib + Saquinavir Contraindicated
- Lapatinib + Thioridazine Contraindicated
- Adagrasib + Lapatinib Major
Frequently asked questions
Can I take Citalopram with Lapatinib?
MediHelp rates the interaction as major. Citalopram and Lapatinib 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, so combining them has an additive effect on cardiac repolarization. This raises the risk of torsades de pointes, especially with electrolyte disturbances, bradycardia or heart disease.
How serious is the interaction between Citalopram and Lapatinib?
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 repeat after initiation, and correct hypokalemia and hypomagnesemia. Consider an alternative antidepressant if the QTc becomes prolonged.
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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