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Does Efavirenz Interact with Voriconazole?

Efavirenz and Voriconazole have a contraindicated drug interaction according to U.S. FDA drug labeling data. CYP450 inducer significantly reduces or slightly decreases voriconazole plasma exposure. Requires dose adjustment if used together. The mechanism involves cyp450 induction. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.

Severity
Contraindicated
Efavirenz Class
Human Immunodeficiency Virus 1 Non-Nucleoside Analog Reverse Transcriptase Inhibitor
Voriconazole Class
Azole Antifungal
Management
Do not take together
Data Source
U.S. FDA via OpenFDA

How This Interaction Works

The interaction between Efavirenz and Voriconazole occurs because cyp450 induction. Clinically, this means cyp450 inducer significantly reduces or slightly decreases voriconazole plasma exposure. requires dose adjustment if used together. Because of the severity of this interaction, these medications are contraindicated — meaning they should not be taken together under any circumstances. If you are currently taking both, contact your healthcare provider immediately to discuss alternatives.

What To Tell Your Doctor or Pharmacist

If you are taking Efavirenz and your doctor is considering prescribing Voriconazole (or vice versa), make sure to:

  • Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
  • Ask whether the benefits of combining these medications outweigh the risks for your specific situation
  • Ask what symptoms to watch for that would indicate the interaction is causing problems
  • Ask about alternative medications that do not interact with your current regimen
  • Ask how frequently you should be monitored while these are co-prescribed
  • Never stop or change either medication without first consulting your healthcare provider
💊 Efavirenz(Efavirenz)+💊 Voriconazole

Severity & Interaction Details

⛔
contraindicated
Avoid this combination
FDA labeling lists this pair as contraindicated. The risk outweighs the benefit in nearly all cases.
Severity scale
MinorContra
On record
Yes
Drug A class
Human Immunodeficiency Virus 1 Non-Nucleoside Analog Reverse Transcriptase Inhibitor
Drug B class
Azole Antifungal
Source
NLP:voriconazole

What this means in plain English

CYP450 inducer significantly reduces or slightly decreases voriconazole plasma exposure. Requires dose adjustment if used together.

What the FDA label says

"CYP450 Induction"

📖 Source: NLP:voriconazole

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Data sourced from U.S. FDA drug labeling via openFDA and the NIH National Library of Medicine. For informational purposes only. Always consult your pharmacist or physician.