Drug interactions
Pimozide + Terbutaline
Severity: Major
Pimozide and Terbutaline: 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
Pimozide prolongs the QT interval, and terbutaline can cause hypokalemia and tachycardia, which increase the risk of torsades de pointes. The combined effect may raise the risk of serious ventricular arrhythmia, particularly with higher terbutaline doses or systemic use.
What this interaction means in plain words
Pimozide and Terbutaline 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.
Pimozide belongs to Central Nervous System; Terbutaline belongs to Respiratory.
Why it happens
Additive proarrhythmic risk from pimozide-induced QT prolongation and beta-2 agonist-induced hypokalemia and sympathetic stimulation.
What to do
Avoid the combination where possible, or monitor ECG and serum potassium and correct hypokalemia before and during therapy. Choose an alternative bronchodilator or antipsychotic if the patient has other QT risk factors.
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 Terbutaline
Other interactions of Pimozide
- Adagrasib + Pimozide Contraindicated
- Amiodarone + Pimozide Contraindicated
- Amisulpride + Pimozide Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amoxapine + Pimozide Contraindicated
- Anagrelide + Pimozide Contraindicated
Frequently asked questions
Can I take Pimozide with Terbutaline?
MediHelp rates the interaction as major. Pimozide and Terbutaline 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. Pimozide prolongs the QT interval, and terbutaline can cause hypokalemia and tachycardia, which increase the risk of torsades de pointes. The combined effect may raise the risk of serious ventricular arrhythmia, particularly with higher terbutaline doses or systemic use.
How serious is the interaction between Pimozide and Terbutaline?
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, or monitor ECG and serum potassium and correct hypokalemia before and during therapy. Choose an alternative bronchodilator or antipsychotic if the patient has other QT risk factors.
What other medicines interact with Terbutaline?
MediHelp also lists interactions of Terbutaline with, for example, Carvedilol, Droperidol, Fexinidazole. The full list is on the Terbutaline page.
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