Drug interactions
Amiodarone + Metronidazole
Severity: Major
Amiodarone and Metronidazole: 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, and metronidazole has been linked to QT prolongation and torsades de pointes in case reports. Combined use may add to arrhythmia risk, especially with electrolyte disturbances or other QT-prolonging drugs.
What this interaction means in plain words
Amiodarone and Metronidazole 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.
Amiodarone belongs to Cardiovascular; Metronidazole belongs to Anti Parasitic.
Why it happens
Additive QT prolongation; the CYP3A4 effect cited in older sources is not well established.
What to do
Obtain a baseline ECG and correct potassium and magnesium before combining. Monitor the QTc and choose an alternative antimicrobial if the QTc becomes markedly prolonged.
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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Other interactions of Metronidazole
- Ethanol + Metronidazole Contraindicated
- Metronidazole + Pimozide Contraindicated
- Disulfiram + Metronidazole Major
- Ergotamine + Metronidazole Major
- Lomitapide + Metronidazole Major
- Lonafarnib + Metronidazole Major
Other interactions of Amiodarone
- Amiodarone + Amisulpride Contraindicated
- Amiodarone + Arsenic trioxide Contraindicated
- Amiodarone + Dofetilide Contraindicated
- Amiodarone + Dronedarone Contraindicated
- Amiodarone + Droperidol Contraindicated
- Amiodarone + Eliglustat Contraindicated
Frequently asked questions
Can I take Amiodarone with Metronidazole?
MediHelp rates the interaction as major. Amiodarone and Metronidazole 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, and metronidazole has been linked to QT prolongation and torsades de pointes in case reports. Combined use may add to arrhythmia risk, especially with electrolyte disturbances or other QT-prolonging drugs.
How serious is the interaction between Amiodarone and Metronidazole?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain a baseline ECG and correct potassium and magnesium before combining. Monitor the QTc and choose an alternative antimicrobial if the QTc becomes markedly prolonged.
What other medicines interact with Metronidazole?
MediHelp also lists interactions of Metronidazole with, for example, Ethanol, Pimozide, Disulfiram. The full list is on the Metronidazole page.
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