Drug interactions
Efavirenz + Marijuana
Severity: Minor
Efavirenz and Marijuana: 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 cannabinoid levels because THC and cannabidiol are partly metabolized by CYP3A4. Both can also cause CNS effects, so additive dizziness or impaired cognition may occur.
What this interaction means in plain words
Efavirenz and Marijuana have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Efavirenz induces CYP3A4, which contributes to cannabinoid metabolism; CNS effects may be additive.
What to do
Advise patients about possible variable cannabis effects and additive CNS effects, and caution on driving.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Efavirenz and Marijuana, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
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
Frequently asked questions
Can I take Efavirenz with Marijuana?
MediHelp rates the interaction as minor. Efavirenz and Marijuana 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 cannabinoid levels because THC and cannabidiol are partly metabolized by CYP3A4. Both can also cause CNS effects, so additive dizziness or impaired cognition may occur.
How serious is the interaction between Efavirenz and Marijuana?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Advise patients about possible variable cannabis effects and additive CNS effects, and caution on driving.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
