Drug interactions
Moxifloxacin + Trimethoprim
Severity: Minor
Moxifloxacin and Trimethoprim: minor 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
Trimethoprim has uncommonly been linked to QT prolongation and arrhythmia, mainly with hyperkalemia or other risk factors. Combined with moxifloxacin, additive QT effects are possible but the evidence is limited.
What this interaction means in plain words
Moxifloxacin and Trimethoprim have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Moxifloxacin belongs to Anti Bacterial; Trimethoprim belongs to Anti Bacterial.
Why it happens
Possible additive QT prolongation; the mechanism for trimethoprim is not well established.
What to do
Monitor ECG and potassium in patients with heart disease, renal impairment or other QT risk factors.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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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 Trimethoprim
Frequently asked questions
Can I take Moxifloxacin with Trimethoprim?
MediHelp rates the interaction as minor. Moxifloxacin and Trimethoprim have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Trimethoprim has uncommonly been linked to QT prolongation and arrhythmia, mainly with hyperkalemia or other risk factors. Combined with moxifloxacin, additive QT effects are possible but the evidence is limited.
How serious is the interaction between Moxifloxacin and Trimethoprim?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor ECG and potassium in patients with heart disease, renal impairment or other QT risk factors.
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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