Drug interactions
Efavirenz + Quazepam
Severity: Moderate
Efavirenz and Quazepam: 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 induces CYP3A4 and may reduce quazepam exposure, weakening its hypnotic effect. Efavirenz itself causes CNS effects such as dizziness and sleep disturbance, so additive sedation and psychomotor impairment are possible.
What this interaction means in plain words
Efavirenz and Quazepam 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
Efavirenz induces CYP3A4 metabolism of quazepam, with additive CNS effects.
What to do
Monitor sleep response and daytime sedation, and adjust the quazepam dose accordingly. Advise caution with driving and other hazardous tasks.
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 Efavirenz with Quazepam?
MediHelp rates the interaction as moderate. Efavirenz and Quazepam 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 induces CYP3A4 and may reduce quazepam exposure, weakening its hypnotic effect. Efavirenz itself causes CNS effects such as dizziness and sleep disturbance, so additive sedation and psychomotor impairment are possible.
How serious is the interaction between Efavirenz and Quazepam?
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 sleep response and daytime sedation, and adjust the quazepam dose accordingly. Advise caution with driving and other hazardous tasks.
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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