Drug interactions
Arsenic trioxide + Clarithromycin
Severity: Major
Arsenic trioxide and Clarithromycin: 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
Arsenic trioxide markedly prolongs the QT interval and can cause torsades de pointes, and clarithromycin adds further QT prolongation. Together they increase the risk of life-threatening arrhythmia.
What this interaction means in plain words
Arsenic trioxide and Clarithromycin 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.
Arsenic trioxide belongs to Oncology; Clarithromycin belongs to Anti Bacterial.
Why it happens
Additive pharmacodynamic QT prolongation.
What to do
Avoid the combination and choose an antibiotic without QT effects. If unavoidable, monitor ECG frequently and keep potassium and magnesium within normal range.
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
Other interactions of Clarithromycin
- Astemizole + Clarithromycin Contraindicated
- Avanafil + Clarithromycin Contraindicated
- Cisapride + Clarithromycin Contraindicated
- Clarithromycin + Colchicine Contraindicated
- Clarithromycin + Conivaptan Contraindicated
- Clarithromycin + Dihydroergotamine Contraindicated
Other interactions of Arsenic trioxide
- Amiodarone + Arsenic trioxide Contraindicated
- Amisulpride + Arsenic trioxide Contraindicated
- Arsenic trioxide + Clomipramine Contraindicated
- Arsenic trioxide + Dronedarone Contraindicated
- Arsenic trioxide + Fluphenazine Contraindicated
- Arsenic trioxide + Gemifloxacin Contraindicated
Frequently asked questions
Can I take Arsenic trioxide with Clarithromycin?
MediHelp rates the interaction as major. Arsenic trioxide and Clarithromycin 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. Arsenic trioxide markedly prolongs the QT interval and can cause torsades de pointes, and clarithromycin adds further QT prolongation. Together they increase the risk of life-threatening arrhythmia.
How serious is the interaction between Arsenic trioxide and Clarithromycin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination and choose an antibiotic without QT effects. If unavoidable, monitor ECG frequently and keep potassium and magnesium within normal range.
What other medicines interact with Clarithromycin?
MediHelp also lists interactions of Clarithromycin with, for example, Astemizole, Avanafil, Cisapride. The full list is on the Clarithromycin page.
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