Drug interactions
Moxifloxacin + Nortriptyline
Severity: Major
Moxifloxacin and Nortriptyline: 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
Nortriptyline can prolong the QT and QRS intervals, and moxifloxacin adds to the QT effect. This increases the risk of ventricular arrhythmias including torsades de pointes.
What this interaction means in plain words
Moxifloxacin and Nortriptyline 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; Nortriptyline belongs to Central Nervous System.
Why it happens
Additive IKr blockade delaying cardiac repolarization, with tricyclic sodium channel effects on conduction.
What to do
Use an alternative antibiotic if possible. Otherwise obtain a baseline ECG, correct electrolytes and monitor the QTc during therapy.
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 Nortriptyline
- Disopyramide + Nortriptyline Contraindicated
- Dofetilide + Nortriptyline Contraindicated
- Dronedarone + Nortriptyline Contraindicated
- Ibutilide + Nortriptyline Contraindicated
- Isocarboxazid + Nortriptyline Contraindicated
- Methylene blue + Nortriptyline Contraindicated
Frequently asked questions
Can I take Moxifloxacin with Nortriptyline?
MediHelp rates the interaction as major. Moxifloxacin and Nortriptyline 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. Nortriptyline can prolong the QT and QRS intervals, and moxifloxacin adds to the QT effect. This increases the risk of ventricular arrhythmias including torsades de pointes.
How serious is the interaction between Moxifloxacin and Nortriptyline?
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. Otherwise obtain a baseline ECG, correct electrolytes and monitor the QTc during therapy.
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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