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Drug interactions

Haloperidol + Mefloquine

Severity: Major

Haloperidol and Mefloquine: 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 can prolong the QT interval, so combined use raises the risk of torsades de pointes. Mefloquine can also cause neuropsychiatric effects that may complicate treatment of psychiatric illness.

What this interaction means in plain words

Haloperidol 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.

Haloperidol belongs to Central Nervous System; Mefloquine belongs to Anti Parasitic.

Evidence level: Moderate

Why it happens

Additive hERG-mediated QT prolongation; haloperidol may also modestly inhibit CYP3A4.

What to do

Avoid the combination where possible and choose another antimalarial. If it is necessary, check a baseline ECG, correct potassium and magnesium, 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 Haloperidol with Mefloquine?

MediHelp rates the interaction as major. Haloperidol 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. Both drugs can prolong the QT interval, so combined use raises the risk of torsades de pointes. Mefloquine can also cause neuropsychiatric effects that may complicate treatment of psychiatric illness.

How serious is the interaction between Haloperidol 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 where possible and choose another antimalarial. If it is necessary, check a baseline ECG, correct potassium and magnesium, 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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