Drug interactions
Clozapine + Lithium
Severity: Major
Clozapine and Lithium: 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
Clozapine can prolong the QT interval and cause myocarditis and arrhythmias, and lithium may add to cardiac conduction effects. The combination is also associated with neurotoxicity and seizures, and is used in practice only with careful monitoring.
What this interaction means in plain words
Clozapine and Lithium 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.
Clozapine belongs to Central Nervous System; Lithium belongs to Central Nervous System.
Why it happens
Additive effects on cardiac repolarization and pharmacodynamic neurotoxic and seizure-threshold effects.
What to do
Obtain a baseline ECG and monitor it, check electrolytes and lithium levels, and watch for neurological symptoms. Avoid additional QT-prolonging drugs.
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 Lithium
- Lithium + Thioridazine Contraindicated
- Lithium + Vandetanib Contraindicated
- Aceclofenac + Lithium Major
- Acemetacin + Lithium Major
- Amisulpride + Lithium Major
- Amlodipine-benazepril + Lithium Major
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 Clozapine with Lithium?
MediHelp rates the interaction as major. Clozapine and Lithium 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. Clozapine can prolong the QT interval and cause myocarditis and arrhythmias, and lithium may add to cardiac conduction effects. The combination is also associated with neurotoxicity and seizures, and is used in practice only with careful monitoring.
How serious is the interaction between Clozapine and Lithium?
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 it, check electrolytes and lithium levels, and watch for neurological symptoms. Avoid additional QT-prolonging drugs.
What other medicines interact with Lithium?
MediHelp also lists interactions of Lithium with, for example, Thioridazine, Vandetanib, Aceclofenac. The full list is on the Lithium page.
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