Drug interactions
Efavirenz + Tasimelteon
Severity: Moderate
Efavirenz and Tasimelteon: 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
Tasimelteon is metabolised by CYP3A4 and CYP1A2. Efavirenz induces CYP3A4, which can lower tasimelteon exposure and reduce its efficacy.
What this interaction means in plain words
Efavirenz and Tasimelteon 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 belongs to Anti Virals; Tasimelteon belongs to Central Nervous System.
Why it happens
Efavirenz induces CYP3A4, increasing tasimelteon clearance.
What to do
Monitor for loss of efficacy in sleep-wake regulation. Consider an alternative if response declines.
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
Other interactions of Tasimelteon
Frequently asked questions
Can I take Efavirenz with Tasimelteon?
MediHelp rates the interaction as moderate. Efavirenz and Tasimelteon 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. Tasimelteon is metabolised by CYP3A4 and CYP1A2. Efavirenz induces CYP3A4, which can lower tasimelteon exposure and reduce its efficacy.
How serious is the interaction between Efavirenz and Tasimelteon?
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 loss of efficacy in sleep-wake regulation. Consider an alternative if response declines.
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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