Drug interactions
Efavirenz + Quetiapine
Severity: Moderate
Efavirenz and Quetiapine: 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 can prolong the QTc interval, so combined use may increase the risk of torsades de pointes. Efavirenz, as a CYP3A4 inducer, may also lower quetiapine levels and reduce antipsychotic effect.
What this interaction means in plain words
Efavirenz and Quetiapine 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; Quetiapine belongs to Central Nervous System.
Why it happens
Additive QT prolongation and efavirenz induction of CYP3A4-mediated quetiapine metabolism.
What to do
Obtain a baseline ECG and correct electrolyte disturbances. Monitor QTc and clinical response, and titrate quetiapine upward if efficacy is lost.
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 Quetiapine
- Adagrasib + Quetiapine Major
- Amiodarone + Quetiapine Major
- Amisulpride + Quetiapine Major
- Amoxapine + Quetiapine Major
- Anagrelide + Quetiapine Major
- Apalutamide + Quetiapine Major
Frequently asked questions
Can I take Efavirenz with Quetiapine?
MediHelp rates the interaction as moderate. Efavirenz and Quetiapine 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 can prolong the QTc interval, so combined use may increase the risk of torsades de pointes. Efavirenz, as a CYP3A4 inducer, may also lower quetiapine levels and reduce antipsychotic effect.
How serious is the interaction between Efavirenz and Quetiapine?
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 electrolyte disturbances. Monitor QTc and clinical response, and titrate quetiapine upward if efficacy is lost.
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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