Drug interactions
levofloxacin + ondansetron
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.
Overview
Additive QT prolongation increases risk of torsades de pointes, especially with IV ondansetron, high doses, baseline QTc prolongation, bradycardia, or electrolyte disturbances.
Mechanism of action
Pharmacodynamic: both can block cardiac IKr (hERG) channels → QT prolongation; effects are additive.
Clinical management
Avoid if possible in patients with QT risk factors. If coadministered, use lowest effective ondansetron dose, correct K/Mg/Ca, obtain baseline/follow-up ECGs, and monitor for palpitations, dizziness, or syncope.
Drug reference
References
- Zofran (ondansetron) Prescribing Information — FDA Label
- Levofloxacin Prescribing Information — FDA Label
- Levofloxacin and ondansetron Interactions — Drugs.com
Frequently asked questions
Can I take levofloxacin with ondansetron?
The interaction is rated: Major. Additive QT prolongation increases risk of torsades de pointes, especially with IV ondansetron, high doses, baseline QTc prolongation, bradycardia, or electrolyte disturbances.
How serious is the interaction between levofloxacin and ondansetron?
The interaction is rated: Major. Evidence level: High.
How is the interaction between levofloxacin and ondansetron managed?
Avoid if possible in patients with QT risk factors. If coadministered, use lowest effective ondansetron dose, correct K/Mg/Ca, obtain baseline/follow-up ECGs, and monitor for palpitations, dizziness, or syncope.
Why do levofloxacin and ondansetron interact?
Pharmacodynamic: both can block cardiac IKr (hERG) channels → QT prolongation; effects are additive.
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