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Drug interactions

Moxifloxacin + Perphenazine

Severity: Major

Moxifloxacin and Perphenazine: major interaction.

Last updated Sources: Health Canada product monograph

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

Perphenazine, like other phenothiazines, can prolong the QT interval, and moxifloxacin adds to this. Combined use raises the risk of torsades de pointes.

What this interaction means in plain words

Moxifloxacin and Perphenazine 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.

Moxifloxacin belongs to Anti Bacterial; Perphenazine belongs to Central Nervous System.

Evidence level: Moderate

Why it happens

Additive hERG channel blockade delaying ventricular repolarization.

What to do

Prefer a non-QT-prolonging antibiotic. If both are needed, 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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References

Frequently asked questions

Can I take Moxifloxacin with Perphenazine?

MediHelp rates the interaction as major. Moxifloxacin and Perphenazine 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. Perphenazine, like other phenothiazines, can prolong the QT interval, and moxifloxacin adds to this. Combined use raises the risk of torsades de pointes.

How serious is the interaction between Moxifloxacin and Perphenazine?

MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer a non-QT-prolonging antibiotic. If both are needed, obtain a baseline ECG, correct electrolytes and monitor the QTc.

What other medicines interact with Moxifloxacin?

MediHelp also lists interactions of Moxifloxacin with, for example, Amiodarone, Arsenic trioxide, Disopyramide. The full list is on the Moxifloxacin page.

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