Drug interactions
Efavirenz + Olanzapine
Severity: Moderate
Efavirenz and Olanzapine: 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 and olanzapine may both prolong the QT interval, although olanzapine has a relatively low risk. Efavirenz may also lower olanzapine exposure through enzyme induction.
What this interaction means in plain words
Efavirenz and Olanzapine 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; Olanzapine belongs to Central Nervous System.
Why it happens
Additive QT effects, plus possible induction of olanzapine metabolism (CYP1A2/UGT) by efavirenz.
What to do
Monitor psychiatric response and adjust olanzapine dose if needed. Obtain an ECG in patients with additional QT risk factors.
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 Olanzapine
Frequently asked questions
Can I take Efavirenz with Olanzapine?
MediHelp rates the interaction as moderate. Efavirenz and Olanzapine 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 and olanzapine may both prolong the QT interval, although olanzapine has a relatively low risk. Efavirenz may also lower olanzapine exposure through enzyme induction.
How serious is the interaction between Efavirenz and Olanzapine?
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 adjust olanzapine dose if needed. Obtain an ECG in patients with additional QT risk factors.
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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