Drug interactions
Butabarbital + Efavirenz
Severity: Moderate
Butabarbital 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
Barbiturates induce CYP enzymes and may lower efavirenz levels, risking loss of virologic control. Additive sedation is also possible.
What this interaction means in plain words
Butabarbital 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.
Why it happens
CYP3A4 and CYP2B6 induction by butabarbital increases efavirenz clearance.
What to do
Monitor HIV viral load and consider efavirenz concentrations; prefer a non-inducing sedative.
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
Frequently asked questions
Can I take Butabarbital with Efavirenz?
MediHelp rates the interaction as moderate. Butabarbital 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. Barbiturates induce CYP enzymes and may lower efavirenz levels, risking loss of virologic control. Additive sedation is also possible.
How serious is the interaction between Butabarbital 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 HIV viral load and consider efavirenz concentrations; prefer a non-inducing sedative.
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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