Drug interactions
Granisetron + Pimavanserin
Severity: Major
Granisetron and Pimavanserin: major interaction.
Last updated Sources: US FDA label
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
Pimavanserin prolongs the QT interval in a dose-related way, and granisetron can add a modest effect. The combination may increase the risk of ventricular arrhythmias including torsades de pointes.
What this interaction means in plain words
Granisetron and Pimavanserin 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.
Granisetron belongs to Gastrointestinal Tract; Pimavanserin belongs to Central Nervous System.
Why it happens
Additive prolongation of cardiac repolarisation.
What to do
Avoid the combination where possible and choose an antiemetic without QT effect. If both are essential, correct electrolytes and monitor the 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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References
Other interactions of Granisetron
- Apomorphine + Granisetron Contraindicated
- Amiodarone + Granisetron Major
- Amisulpride + Granisetron Major
- Arsenic trioxide + Granisetron Major
- Artemether / lumefantrine + Granisetron Major
- Artemether + Granisetron Major
Other interactions of Pimavanserin
- Lefamulin + Pimavanserin Contraindicated
- Pimavanserin + Pimozide Contraindicated
- Pimavanserin + Vandetanib Contraindicated
- Adagrasib + Pimavanserin Major
- Amiodarone + Pimavanserin Major
- Amisulpride + Pimavanserin Major
Frequently asked questions
Can I take Granisetron with Pimavanserin?
MediHelp rates the interaction as major. Granisetron and Pimavanserin 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. Pimavanserin prolongs the QT interval in a dose-related way, and granisetron can add a modest effect. The combination may increase the risk of ventricular arrhythmias including torsades de pointes.
How serious is the interaction between Granisetron and Pimavanserin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible and choose an antiemetic without QT effect. If both are essential, correct electrolytes and monitor the ECG.
What other medicines interact with Granisetron?
MediHelp also lists interactions of Granisetron with, for example, Apomorphine, Amiodarone, Amisulpride. The full list is on the Granisetron page.
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