Drug interactions
Olanzapine + Pefloxacin
Severity: Moderate
Olanzapine and Pefloxacin: moderate 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, the main enzyme metabolising olanzapine, and may raise olanzapine levels with more sedation, hypotension and anticholinergic effects. Fluoroquinolones can also prolong the QT interval.
What this interaction means in plain words
Olanzapine and Pefloxacin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Olanzapine belongs to Central Nervous System; Pefloxacin belongs to Anti Bacterial.
Why it happens
CYP1A2 inhibition by pefloxacin decreases olanzapine clearance, with additional QT effects.
What to do
Monitor for sedation, hypotension and QT changes, and consider reducing the olanzapine dose during therapy. Choose an antibiotic without CYP1A2 inhibition if possible.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Olanzapine
Other interactions of Pefloxacin
- Pefloxacin + Tizanidine Contraindicated
- Clozapine + Pefloxacin Major
- Duloxetine + Pefloxacin Major
- Pefloxacin + Theophylline Major
- Asenapine + Pefloxacin Moderate
- Caffeine + Pefloxacin Moderate
Frequently asked questions
Can I take Olanzapine with Pefloxacin?
MediHelp rates the interaction as moderate. Olanzapine and Pefloxacin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Pefloxacin inhibits CYP1A2, the main enzyme metabolising olanzapine, and may raise olanzapine levels with more sedation, hypotension and anticholinergic effects. Fluoroquinolones can also prolong the QT interval.
How serious is the interaction between Olanzapine and Pefloxacin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for sedation, hypotension and QT changes, and consider reducing the olanzapine dose during therapy. Choose an antibiotic without CYP1A2 inhibition if possible.
What other medicines interact with Olanzapine?
MediHelp also lists interactions of Olanzapine with, for example, Amisulpride, Amoxapine, Apomorphine. The full list is on the Olanzapine page.
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