Drug interactions
Efavirenz + Fluoxetine
Severity: Moderate
Efavirenz and Fluoxetine: 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 can prolong the QT interval, so combined use may add to the risk of ventricular arrhythmia including torsades de pointes. The risk is greater with electrolyte disturbances, heart disease or other QT-prolonging drugs.
What this interaction means in plain words
Efavirenz and Fluoxetine 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; Fluoxetine belongs to Central Nervous System.
Why it happens
Additive pharmacodynamic QT prolongation.
What to do
Obtain a baseline ECG and correct potassium and magnesium abnormalities. Repeat ECG monitoring in patients with additional risk factors, or consider an alternative antidepressant.
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 Efavirenz
- Cobimetinib + Efavirenz Contraindicated
- Dienogest / estradiol valerate + Efavirenz Contraindicated
- Dihydroergotamine intranasal + Efavirenz Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Doravirine + Efavirenz Contraindicated
- Efavirenz + Elbasvir / grazoprevir Contraindicated
Other interactions of Fluoxetine
- Fluoxetine + Isocarboxazid Contraindicated
- Fluoxetine + Mavacamten Contraindicated
- Fluoxetine + Methylene blue Contraindicated
- Fluoxetine + Phenelzine Contraindicated
- Fluoxetine + Pimozide Contraindicated
- Fluoxetine + Rasagiline Contraindicated
Frequently asked questions
Can I take Efavirenz with Fluoxetine?
MediHelp rates the interaction as moderate. Efavirenz and Fluoxetine 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 can prolong the QT interval, so combined use may add to the risk of ventricular arrhythmia including torsades de pointes. The risk is greater with electrolyte disturbances, heart disease or other QT-prolonging drugs.
How serious is the interaction between Efavirenz and Fluoxetine?
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 a baseline ECG and correct potassium and magnesium abnormalities. Repeat ECG monitoring in patients with additional risk factors, or consider an alternative antidepressant.
What other medicines interact with Efavirenz?
MediHelp also lists interactions of Efavirenz with, for example, Cobimetinib, Dienogest / estradiol valerate, Dihydroergotamine intranasal. The full list is on the Efavirenz page.
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