Drug interactions
Dofetilide + Olanzapine
Severity: Major
Dofetilide and Olanzapine: major interaction.
Last updated Sources: UK SmPC
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
Dofetilide markedly prolongs the QT interval and can cause torsades de pointes. Olanzapine has a small QT effect, so the combination may add to arrhythmic risk, particularly with electrolyte disturbances or renal impairment.
What this interaction means in plain words
Dofetilide and Olanzapine 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.
Dofetilide belongs to Cardiovascular; Olanzapine belongs to Central Nervous System.
Why it happens
Additive QT prolongation through cardiac repolarization effects.
What to do
Avoid the combination if an alternative exists. If used, monitor ECG and QTc and keep potassium and magnesium within normal limits.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Dofetilide and Olanzapine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
References
- Olanzapine 10 mg orodispersible tablets - SmPC sections 4.3/4.5 (class statement: medicinal products known to increase QTc interval; "Caution should be used if olanzapine is being administered concomitantly with medicinal products known to increase QTc interval (see section 4.4).") — electronic medicines compendium (UK SmPC)
Other interactions of Olanzapine
Other interactions of Dofetilide
- Amiodarone + Dofetilide Contraindicated
- Amisulpride + Dofetilide Contraindicated
- Amlodipine-hydrochlorothiazide-valsartan + Dofetilide Contraindicated
- Amlodipine-olmesartan-hydrochlorothiazide + Dofetilide Contraindicated
- Candesartan-hydrochlorothiazide + Dofetilide Contraindicated
- Captopril-hydrochlorothiazide + Dofetilide Contraindicated
Frequently asked questions
Can I take Dofetilide with Olanzapine?
MediHelp rates the interaction as major. Dofetilide and Olanzapine 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. Dofetilide markedly prolongs the QT interval and can cause torsades de pointes. Olanzapine has a small QT effect, so the combination may add to arrhythmic risk, particularly with electrolyte disturbances or renal impairment.
How serious is the interaction between Dofetilide and Olanzapine?
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 if an alternative exists. If used, monitor ECG and QTc and keep potassium and magnesium within normal limits.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
