Drug interactions
Diazepam + Efavirenz
Severity: Moderate
Diazepam and Efavirenz: 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 can induce CYP3A4 and may lower diazepam concentrations, but efavirenz also inhibits CYP2C19 and has mixed effects. Efavirenz itself causes CNS effects such as dizziness and somnolence that may be additive.
What this interaction means in plain words
Diazepam and Efavirenz 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.
Diazepam belongs to Musculoskeletal; Efavirenz belongs to Anti Virals.
Why it happens
Mixed CYP3A4 induction and CYP2C19 inhibition by efavirenz alters diazepam metabolism, with additive CNS effects.
What to do
Monitor for changes in diazepam effect and for additive CNS adverse effects; adjust the diazepam dose according to 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 Diazepam
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 Diazepam with Efavirenz?
MediHelp rates the interaction as moderate. Diazepam and Efavirenz 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 can induce CYP3A4 and may lower diazepam concentrations, but efavirenz also inhibits CYP2C19 and has mixed effects. Efavirenz itself causes CNS effects such as dizziness and somnolence that may be additive.
How serious is the interaction between Diazepam and Efavirenz?
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 for changes in diazepam effect and for additive CNS adverse effects; adjust the diazepam dose according to response.
What other medicines interact with Diazepam?
MediHelp also lists interactions of Diazepam with, for example, Calcium / magnesium / potassium / sodium oxybates, Alfentanil, Alprazolam. The full list is on the Diazepam page.
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