Drug interactions
Clozapine + Lefamulin
Severity: Major
Clozapine and Lefamulin: 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
Lefamulin and clozapine each can lengthen the QT interval, so used together they may increase the risk of torsades de pointes. The risk is higher with electrolyte disturbances, bradycardia or structural heart disease.
What this interaction means in plain words
Clozapine and Lefamulin 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; Lefamulin belongs to Anti Bacterial.
Why it happens
Additive prolongation of cardiac repolarization (QTc).
What to do
Prefer an alternative antibiotic when possible. If the combination is needed, check baseline ECG, correct potassium and magnesium, and monitor QTc.
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
- Clozapine Viatris 100 mg Orodispersible Tablets - SmPC sections 4.3/4.5 (class statement: medicines known to increase QTc interval; "caution should be exercised when clozapine is prescribed with medicines known to increase QTc interval, or causing electrolyte imbalance.") — electronic medicines compendium (UK SmPC)
Other interactions of Clozapine
- Clozapine + Deferiprone Contraindicated
- Clozapine + Irinotecan Contraindicated
- Clozapine + Pimozide Contraindicated
- Clozapine + Thioridazine Contraindicated
- Acalabrutinib + Clozapine Major
- Adagrasib + Clozapine Major
Other interactions of Lefamulin
- Lefamulin + Methadone Contraindicated
- Lefamulin + Pimavanserin Contraindicated
- Lefamulin + Pimozide Contraindicated
- Lefamulin + Quinidine Contraindicated
- Alfuzosin + Lefamulin Major
- Amiodarone + Lefamulin Major
Frequently asked questions
Can I take Clozapine with Lefamulin?
MediHelp rates the interaction as major. Clozapine and Lefamulin 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. Lefamulin and clozapine each can lengthen the QT interval, so used together they may increase the risk of torsades de pointes. The risk is higher with electrolyte disturbances, bradycardia or structural heart disease.
How serious is the interaction between Clozapine and Lefamulin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer an alternative antibiotic when possible. If the combination is needed, check baseline ECG, correct potassium and magnesium, and monitor QTc.
What other medicines interact with Clozapine?
MediHelp also lists interactions of Clozapine with, for example, Deferiprone, Irinotecan, Pimozide. The full list is on the Clozapine page.
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