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Drug interactions

Mefloquine + Toremifene

Severity: Major

Mefloquine and Toremifene: 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

Both drugs prolong the QT interval and toremifene labeling cautions against use with other QT-prolonging drugs. Together they may increase the risk of torsades de pointes.

What this interaction means in plain words

Mefloquine and Toremifene 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 belongs to Anti Parasitic; Toremifene belongs to Endocrine.

Evidence level: Moderate

Why it happens

Additive prolongation of cardiac repolarization (QTc).

What to do

Avoid the combination and use a non-QT-prolonging antimalarial. If it cannot be avoided, obtain a baseline ECG, correct electrolytes, and monitor the QTc.

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?

Bring a full list of your medicines, including over-the-counter products, supplements and herbal remedies, to every pharmacy visit.

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Frequently asked questions

Can I take Mefloquine with Toremifene?

MediHelp rates the interaction as major. Mefloquine and Toremifene 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. Both drugs prolong the QT interval and toremifene labeling cautions against use with other QT-prolonging drugs. Together they may increase the risk of torsades de pointes.

How serious is the interaction between Mefloquine and Toremifene?

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 a non-QT-prolonging antimalarial. If it cannot be avoided, obtain a baseline ECG, correct electrolytes, and monitor the QTc.

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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