Drug interactions
Azithromycin + Vemurafenib
Severity: Major
Azithromycin and Vemurafenib: 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
Vemurafenib can prolong the QT interval in an exposure-dependent way, and azithromycin has similar potential. Concurrent use may add to the risk of serious ventricular arrhythmia.
What this interaction means in plain words
Azithromycin and Vemurafenib 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.
Azithromycin belongs to Anti Bacterial; Vemurafenib belongs to Oncology.
Why it happens
Additive QT interval prolongation via effects on cardiac repolarization.
What to do
Prefer an antibiotic without QT effects. If the combination is needed, check ECG and electrolytes at baseline and periodically, and stop or reduce vemurafenib if 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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References
- Azithromycin 200mg/5ml Powder for Oral Suspension - SmPC sections 4.3/4.5 (class statement: medicinal products known to prolong the QT interval; "Azithromycin should be used with caution in patients receiving medicinal products known to prolong the QT interval") — electronic medicines compendium (UK SmPC)
Other interactions of Azithromycin
- Azithromycin + Cisapride Contraindicated
- Azithromycin + Domperidone Contraindicated
- Azithromycin + Dronedarone Contraindicated
- Azithromycin + Pimozide Contraindicated
- Azithromycin + Piperaquine Contraindicated
- Azithromycin + Thioridazine Contraindicated
Other interactions of Vemurafenib
Frequently asked questions
Can I take Azithromycin with Vemurafenib?
MediHelp rates the interaction as major. Azithromycin and Vemurafenib 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. Vemurafenib can prolong the QT interval in an exposure-dependent way, and azithromycin has similar potential. Concurrent use may add to the risk of serious ventricular arrhythmia.
How serious is the interaction between Azithromycin and Vemurafenib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer an antibiotic without QT effects. If the combination is needed, check ECG and electrolytes at baseline and periodically, and stop or reduce vemurafenib if QTc becomes markedly prolonged.
What other medicines interact with Azithromycin?
MediHelp also lists interactions of Azithromycin with, for example, Cisapride, Domperidone, Dronedarone. The full list is on the Azithromycin page.
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