What the FDA labels say about taking them together
Efavirenz and voriconazole
Efavirenz's FDA label of March 31, 2024 names voriconazole in its drug interactions section, and voriconazole's label names efavirenz too. The voriconazole label: “Contraindicated”
Check it at the source: the efavirenz FDA label on DailyMed (effective March 31, 2024, Cipla USA Inc.); the voriconazole FDA label on DailyMed (effective February 26, 2026, Roerig).
What does the efavirenz label say about voriconazole?
Efavirenz label, drug interactionsConcomitant Drug Class/Drug Name: Antifungals: Voriconazole Itraconazole Ketoconazole Posaconazole; Effect: ↓ voriconazole * ↑ efavirenz * ↓ itraconazole * ↓ hydroxy itraconazole * ↓ ketoconazole ↓ posaconazole *; Clinical Comment: Efavirenz and voriconazole should not be coadministered at standard doses. When voriconazole is coadministered with efavirenz, voriconazole maintenance dose should be increased to 400 mg every 12 hours and efavirenz dose should be decreased to 300 mg once daily using the capsule formulation. Efavirenz tablets must not be broken. [see Dosage and Administration () and Clinical Pharmacology (, and)]. …
Source: FDA drug label (Efavirenz), Cipla USA Inc., effective March 31, 2024 (SPL set 92603fa5-7a2c-4bfb-9a70-aadb4fba952c), via openFDA; the full label on DailyMed
What does the voriconazole label say about efavirenz?
Voriconazole label, contraindicationsEfavirenz Concomitant use with efavirenz dosages of 400 mg every 24 hours or higher is contraindicated [see Clinical Pharmacology (12.3) ].
Voriconazole label, drug interactionsDrug/Drug Class (Mechanism of Interaction by the Drug): Efavirenz (400 mg every 24 hours) Results based on in vivo clinical study following repeat oral dosing with 400 mg every 12 hours for 1 day, then 200 mg every 12 hours for at least 2 days voriconazole to healthy subjects (CYP450 Induction); Voriconazole Plasma Exposure (C max and AUC τ after 200 mg every 12 hours): Significantly Reduced; Prevention or Management Recommendations: Contraindicated
Voriconazole label (Xellia Pharmaceuticals USA LLC, January 11, 2023), contraindicationsCoadministration of standard doses of voriconazole with efavirenz doses of 400 mg every 24 hours or higher is contraindicated, because efavirenz significantly decreases plasma voriconazole concentrations in healthy subjects at these doses.
Voriconazole label (Xellia Pharmaceuticals USA LLC, January 11, 2023), drug interactionsDrug/Drug Class (Mechanism of Interaction by the Drug): Efavirenz (400 mg every 24 hours) (CYP450 Induction); Voriconazole Plasma Exposure (C max and AUC τ after 200 mg every 12 hours): Significantly Reduced; Recommendations for Voriconazole Dosage Adjustment/Comments: Contraindicated
Source: FDA drug label (Voriconazole, NDA208562), Xellia Pharmaceuticals USA LLC, effective January 11, 2023 (SPL set 9ec6eda2-2f15-423b-9ec6-819379a426e1), via openFDA
Source: FDA drug label (VFEND), NDA021630 (Pf Prism Cv), as published by Roerig, effective February 26, 2026 (SPL set ce3ef5cf-3087-4d92-9d94-9eb8287228db), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Efavirenz | Voriconazole | |
|---|---|---|
| Labeled for | HIV | Fungal infections |
| Boxed warning | No | No |
| Pharmacy cost (NADAC) | $1.28 per tablet 600 mg tablet | $1.88 per tablet 200 mg tablet |
| Shortage now | No current entry | A presentation being discontinued |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once