Drug interactions
Azithromycin + Efavirenz
Severity: Moderate
Azithromycin and Efavirenz: moderate 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
Both agents have been associated with QT interval prolongation, so combined use may increase the risk of ventricular arrhythmia such as torsades de pointes. The risk is greater with electrolyte disturbances or underlying heart disease.
What this interaction means in plain words
Azithromycin and Efavirenz can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Azithromycin belongs to Anti Bacterial; Efavirenz belongs to Anti Virals.
Why it happens
Additive prolongation of cardiac repolarization (QTc); efavirenz does not meaningfully alter azithromycin pharmacokinetics.
What to do
Obtain an ECG and correct potassium and magnesium before combining, especially in patients with other QT risk factors. Consider an alternative antibiotic in high-risk patients.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Efavirenz
- Cobimetinib + Efavirenz Contraindicated
- Dienogest / estradiol valerate + Efavirenz Contraindicated
- Dihydroergotamine intranasal + Efavirenz Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Doravirine + Efavirenz Contraindicated
- Efavirenz + Elbasvir / grazoprevir Contraindicated
Frequently asked questions
Can I take Azithromycin with Efavirenz?
MediHelp rates the interaction as moderate. Azithromycin and Efavirenz can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both agents have been associated with QT interval prolongation, so combined use may increase the risk of ventricular arrhythmia such as torsades de pointes. The risk is greater with electrolyte disturbances or underlying heart disease.
How serious is the interaction between Azithromycin and Efavirenz?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain an ECG and correct potassium and magnesium before combining, especially in patients with other QT risk factors. Consider an alternative antibiotic in high-risk patients.
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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