Drug interactions
Dofetilide + Mexiletine
Severity: Major
Dofetilide and Mexiletine: 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
Dofetilide prolongs repolarization and can cause torsades de pointes. Mexiletine shortens the action potential and has less QT effect, but both are antiarrhythmics with proarrhythmic potential. Combined use is not well studied.
What this interaction means in plain words
Dofetilide and Mexiletine 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; Mexiletine belongs to Cardiovascular.
Why it happens
Additive antiarrhythmic and proarrhythmic electrophysiologic effects.
What to do
Avoid unless specialist-directed; if used, monitor ECG, QTc and electrolytes, especially during dofetilide initiation in hospital.
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 Mexiletine, 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 14 days on the web. No card needed.
Other interactions of Mexiletine
- Fezolinetant + Mexiletine Contraindicated
- Mexiletine + Pimozide Contraindicated
- Alosetron + Mexiletine Major
- Amiodarone + Mexiletine Major
- Clozapine + Mexiletine Major
- Cobicistat + Mexiletine Major
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 Mexiletine?
MediHelp rates the interaction as major. Dofetilide and Mexiletine 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 prolongs repolarization and can cause torsades de pointes. Mexiletine shortens the action potential and has less QT effect, but both are antiarrhythmics with proarrhythmic potential. Combined use is not well studied.
How serious is the interaction between Dofetilide and Mexiletine?
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 unless specialist-directed; if used, monitor ECG, QTc and electrolytes, especially during dofetilide initiation in hospital.
What other medicines interact with Mexiletine?
MediHelp also lists interactions of Mexiletine with, for example, Fezolinetant, Pimozide, Alosetron. The full list is on the Mexiletine 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.
