Drug interactions
Efavirenz + Haloperidol
Severity: Moderate
Efavirenz and Haloperidol: 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
Efavirenz may lower haloperidol concentrations through enzyme induction, reducing antipsychotic effect. Both drugs can also prolong the QT interval, adding to arrhythmia risk.
What this interaction means in plain words
Efavirenz and Haloperidol 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; Haloperidol belongs to Central Nervous System.
Why it happens
CYP3A4 induction by efavirenz increases haloperidol clearance, with additive QT prolongation.
What to do
Monitor psychiatric response and ECG, and correct electrolyte abnormalities. Adjust the haloperidol dose according to clinical response.
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 Haloperidol
- Dofetilide + Haloperidol Contraindicated
- Dronedarone + Haloperidol Contraindicated
- Haloperidol + Ibutilide Contraindicated
- Haloperidol + Levoketoconazole Contraindicated
- Haloperidol + Panobinostat Contraindicated
- Haloperidol + Pimozide Contraindicated
Frequently asked questions
Can I take Efavirenz with Haloperidol?
MediHelp rates the interaction as moderate. Efavirenz and Haloperidol 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 may lower haloperidol concentrations through enzyme induction, reducing antipsychotic effect. Both drugs can also prolong the QT interval, adding to arrhythmia risk.
How serious is the interaction between Efavirenz and Haloperidol?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor psychiatric response and ECG, and correct electrolyte abnormalities. Adjust the haloperidol dose according to clinical response.
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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