Drug interactions
Amitriptyline + Moxifloxacin
Severity: Major
Amitriptyline and Moxifloxacin: major interaction.
Last updated Sources: UK SmPC
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 increases the risk of ventricular arrhythmia including torsades de pointes. Risk is greater at higher tricyclic doses or with electrolyte disturbances and cardiac disease.
What this interaction means in plain words
Amitriptyline and Moxifloxacin 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.
Amitriptyline belongs to Central Nervous System; Moxifloxacin belongs to Anti Bacterial.
Why it happens
Additive IKr potassium channel blockade delaying cardiac repolarization.
What to do
Use an alternative antibiotic if possible. If combined, obtain 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?
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References
- Avelox 400 mg film-coated tablets - SmPC sections 4.3/4.5 (class statement: tricyclic antidepressive agents; "tricyclic antidepressive agents") — electronic medicines compendium (UK SmPC)
Other interactions of Moxifloxacin
- Amiodarone + Moxifloxacin Contraindicated
- Arsenic trioxide + Moxifloxacin Contraindicated
- Disopyramide + Moxifloxacin Contraindicated
- Dofetilide + Moxifloxacin Contraindicated
- Dronedarone + Moxifloxacin Contraindicated
- Droperidol + Moxifloxacin Contraindicated
Other interactions of Amitriptyline
- Amitriptyline + Isocarboxazid Contraindicated
- Amitriptyline + Methylene blue Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amitriptyline + Pimozide Contraindicated
- Amitriptyline + Procarbazine Contraindicated
- Amitriptyline + Safinamide Contraindicated
Frequently asked questions
Can I take Amitriptyline with Moxifloxacin?
MediHelp rates the interaction as major. Amitriptyline and Moxifloxacin 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 increases the risk of ventricular arrhythmia including torsades de pointes. Risk is greater at higher tricyclic doses or with electrolyte disturbances and cardiac disease.
How serious is the interaction between Amitriptyline and Moxifloxacin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use an alternative antibiotic if possible. If combined, obtain a baseline ECG, correct potassium and magnesium, 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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