Drug interactions
Clozapine + Pefloxacin
Severity: Major
Clozapine and Pefloxacin: major interaction.
Last updated
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
Pefloxacin inhibits CYP1A2 and can raise clozapine concentrations, increasing the risk of sedation, hypotension, seizures, myocarditis and QT effects. Fluoroquinolones also have their own QT and seizure-lowering effects.
What this interaction means in plain words
Clozapine and Pefloxacin 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; Pefloxacin belongs to Anti Bacterial.
Why it happens
Pefloxacin inhibits CYP1A2, decreasing clozapine clearance.
What to do
Prefer an antibiotic that does not inhibit CYP1A2. If it must be used, reduce the clozapine dose and monitor clinical toxicity, clozapine levels and ECG.
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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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 Pefloxacin
- Pefloxacin + Tizanidine Contraindicated
- Duloxetine + Pefloxacin Major
- Pefloxacin + Theophylline Major
- Asenapine + Pefloxacin Moderate
- Caffeine + Pefloxacin Moderate
- Cimetidine + Pefloxacin Moderate
Frequently asked questions
Can I take Clozapine with Pefloxacin?
MediHelp rates the interaction as major. Clozapine and Pefloxacin 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. Pefloxacin inhibits CYP1A2 and can raise clozapine concentrations, increasing the risk of sedation, hypotension, seizures, myocarditis and QT effects. Fluoroquinolones also have their own QT and seizure-lowering effects.
How serious is the interaction between Clozapine and Pefloxacin?
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 antibiotic that does not inhibit CYP1A2. If it must be used, reduce the clozapine dose and monitor clinical toxicity, clozapine levels and ECG.
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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