Drug interactions
Dofetilide + Mefloquine
Severity: Major
Dofetilide and Mefloquine: 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
Mefloquine and dofetilide both lengthen the QT interval, so combining them raises the risk of torsades de pointes and sudden cardiac death. Dofetilide has a narrow therapeutic index and its safety depends on strict QTc monitoring.
What this interaction means in plain words
Dofetilide and Mefloquine 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; Mefloquine belongs to Anti Parasitic.
Why it happens
Additive QT prolongation; dofetilide blocks the IKr potassium current and mefloquine also affects cardiac repolarization.
What to do
Avoid the combination and use an alternative antimalarial. If it cannot be avoided, monitor the ECG and electrolytes closely.
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 Mefloquine
- Arsenic trioxide + Mefloquine Contraindicated
- Dronedarone + Mefloquine Contraindicated
- Ibutilide + Mefloquine Contraindicated
- Levoketoconazole + Mefloquine Contraindicated
- Mefloquine + Nilotinib Contraindicated
- Mefloquine + Pimozide Contraindicated
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 Mefloquine?
MediHelp rates the interaction as major. Dofetilide and Mefloquine 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. Mefloquine and dofetilide both lengthen the QT interval, so combining them raises the risk of torsades de pointes and sudden cardiac death. Dofetilide has a narrow therapeutic index and its safety depends on strict QTc monitoring.
How serious is the interaction between Dofetilide and Mefloquine?
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 and use an alternative antimalarial. If it cannot be avoided, monitor the ECG and electrolytes closely.
What other medicines interact with Mefloquine?
MediHelp also lists interactions of Mefloquine with, for example, Arsenic trioxide, Dronedarone, Ibutilide. The full list is on the Mefloquine page.
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