Drug interactions
Efavirenz + Istradefylline
Severity: Major
Efavirenz and Istradefylline: major 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 substantially lower istradefylline exposure. This could reduce its benefit as adjunctive therapy for off episodes in Parkinson disease.
What this interaction means in plain words
Efavirenz and Istradefylline can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Efavirenz belongs to Anti Virals; Istradefylline belongs to Central Nervous System.
Why it happens
Efavirenz induction of CYP3A4 increases the metabolic clearance of istradefylline.
What to do
Avoid concomitant use of istradefylline with strong CYP3A4 inducers; consider an alternative antiretroviral regimen or a different Parkinson therapy. Monitor motor response if the combination cannot be avoided.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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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 Istradefylline
Frequently asked questions
Can I take Efavirenz with Istradefylline?
MediHelp rates the interaction as major. Efavirenz and Istradefylline can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Efavirenz induces CYP3A4 and may substantially lower istradefylline exposure. This could reduce its benefit as adjunctive therapy for off episodes in Parkinson disease.
How serious is the interaction between Efavirenz and Istradefylline?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid concomitant use of istradefylline with strong CYP3A4 inducers; consider an alternative antiretroviral regimen or a different Parkinson therapy. Monitor motor response if the combination cannot be avoided.
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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