Drug interactions
Donepezil + Efavirenz
Severity: Minor
Donepezil and Efavirenz: minor 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 reduce donepezil concentrations, potentially weakening its cognitive benefit.
What this interaction means in plain words
Donepezil and Efavirenz have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Donepezil belongs to Central Nervous System; Efavirenz belongs to Anti Virals.
Why it happens
Efavirenz induces CYP3A4 and possibly CYP2D6-related clearance of donepezil.
What to do
Monitor cognitive and functional response and consider a donepezil dose increase if benefit is lost.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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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 Donepezil
- Donepezil + Dronedarone Contraindicated
- Donepezil + Pimozide Contraindicated
- Donepezil + Thioridazine Contraindicated
- Donepezil + Vandetanib Contraindicated
- Amiodarone + Donepezil Major
- Amisulpride + Donepezil Major
Frequently asked questions
Can I take Donepezil with Efavirenz?
MediHelp rates the interaction as minor. Donepezil and Efavirenz have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Efavirenz may reduce donepezil concentrations, potentially weakening its cognitive benefit.
How serious is the interaction between Donepezil and Efavirenz?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor cognitive and functional response and consider a donepezil dose increase if benefit 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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