Drug interactions
Lithium + Ondansetron
Severity: Moderate
Lithium and Ondansetron: 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
Lithium can cause QT prolongation, T-wave changes and sinus node dysfunction, particularly at toxic levels. Ondansetron may add to repolarization effects in susceptible patients.
What this interaction means in plain words
Lithium and Ondansetron 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.
Lithium belongs to Central Nervous System; Ondansetron belongs to Gastrointestinal Tract.
Why it happens
Additive effects on cardiac repolarization and conduction.
What to do
Monitor ECG and serum lithium and electrolytes, particularly in patients with cardiac disease or renal impairment. Avoid in congenital long QT syndrome.
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 Ondansetron
- Apomorphine + Ondansetron Contraindicated
- Ondansetron + Thioridazine Contraindicated
- Ondansetron + Vandetanib Contraindicated
- Adagrasib + Ondansetron Major
- Amiodarone + Ondansetron Major
- Amisulpride + Ondansetron Major
Other interactions of Lithium
- Lithium + Thioridazine Contraindicated
- Lithium + Vandetanib Contraindicated
- Aceclofenac + Lithium Major
- Acemetacin + Lithium Major
- Amisulpride + Lithium Major
- Amlodipine-benazepril + Lithium Major
Frequently asked questions
Can I take Lithium with Ondansetron?
MediHelp rates the interaction as moderate. Lithium and Ondansetron 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. Lithium can cause QT prolongation, T-wave changes and sinus node dysfunction, particularly at toxic levels. Ondansetron may add to repolarization effects in susceptible patients.
How serious is the interaction between Lithium and Ondansetron?
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 ECG and serum lithium and electrolytes, particularly in patients with cardiac disease or renal impairment. Avoid in congenital long QT syndrome.
What other medicines interact with Ondansetron?
MediHelp also lists interactions of Ondansetron with, for example, Apomorphine, Thioridazine, Vandetanib. The full list is on the Ondansetron page.
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