Drug interactions
Efavirenz + Fluconazole
Severity: Moderate
Efavirenz and Fluconazole: 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 drugs have been associated with QT prolongation, and efavirenz may also affect fluconazole exposure only minimally. Combined use adds to arrhythmia risk, particularly with electrolyte disturbance or other QT drugs.
What this interaction means in plain words
Efavirenz and Fluconazole 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.
Efavirenz belongs to Anti Virals; Fluconazole belongs to Anti Fungals.
Why it happens
Additive prolongation of cardiac repolarization.
What to do
Obtain ECG and correct potassium and magnesium in at-risk patients. Avoid adding further QT-prolonging drugs.
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 Fluconazole
- Dihydroergotamine intranasal + Fluconazole Contraindicated
- Dihydroergotamine + Fluconazole Contraindicated
- Dofetilide + Fluconazole Contraindicated
- Dronedarone + Fluconazole Contraindicated
- Erythromycin + Fluconazole Contraindicated
- Flibanserin + Fluconazole 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 Efavirenz with Fluconazole?
MediHelp rates the interaction as moderate. Efavirenz and Fluconazole 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 drugs have been associated with QT prolongation, and efavirenz may also affect fluconazole exposure only minimally. Combined use adds to arrhythmia risk, particularly with electrolyte disturbance or other QT drugs.
How serious is the interaction between Efavirenz and Fluconazole?
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 ECG and correct potassium and magnesium in at-risk patients. Avoid adding further QT-prolonging drugs.
What other medicines interact with Fluconazole?
MediHelp also lists interactions of Fluconazole with, for example, Dihydroergotamine intranasal, Dihydroergotamine, Dofetilide. The full list is on the Fluconazole page.
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