What the FDA labels say about taking them together
Gefitinib and itraconazole
Gefitinib's FDA label of February 28, 2023 names itraconazole in its drug interactions section, and itraconazole's label names gefitinib too. The gefitinib label: “CYP3A4 Inhibitor Drugs that are strong inhibitors of CYP3A4 decrease gefitinib metabolism and increase gefitinib plasma concentrations.”
Check it at the source: the gefitinib FDA label on DailyMed (effective February 28, 2023, AstraZeneca Pharmaceuticals LP); the itraconazole FDA label on DailyMed (effective July 13, 2026, Janssen Pharmaceuticals, Inc.).
What does the gefitinib label say about itraconazole?
Gefitinib label, drug interactionsCYP3A4 Inhibitor Drugs that are strong inhibitors of CYP3A4 (e.g., ketoconazole and itraconazole) decrease gefitinib metabolism and increase gefitinib plasma concentrations.
Source: FDA drug label (IRESSA), AstraZeneca Pharmaceuticals LP, effective February 28, 2023 (SPL set 827d60e8-7e07-41b7-c28b-49ef1c4a5a41), via openFDA; the full label on DailyMed
What does the itraconazole label say about gefitinib?
Itraconazole label, drug interactionsExamples of Concomitant Drugs Within Class: Bortezomib Brentuximab-vedotin Busulfan Erlotinib Gefitinib Idelalisib Imatinib Ixabepilone; Prevention or Management: Nintedanib Panobinostat Ponatinib Ruxolitinib Sonidegib Tretinoin (oral) Vandetanib; Monitor for adverse reactions. Concomitant drug dose reduction may be necessary. For idelalisib, see also.
Tolsura label (Mayne Pharma Commercial LLC, April 23, 2025), drug interactionsBortezomib Brentuximab-vedotin Busulfan Erlotinib Gefitinib Idelalisib Imatinib Ixabepilone Nintedanib Panobinostat Ponatinib Ruxolitinib Sonidegib Vandetanib Monitor for adverse reactions.
Source: FDA drug label (Tolsura, NDA208901), Mayne Pharma Commercial LLC, effective April 23, 2025 (SPL set 306352d1-9d5a-49ad-b72d-893b99546861), via openFDA
Source: FDA drug label (SPORANOX), Janssen Pharmaceuticals, Inc., effective July 13, 2026 (SPL set a4d555fa-787c-40fb-bb7d-b0d4f7318fd0), 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
| Gefitinib | Itraconazole | |
|---|---|---|
| Labeled for | Lung cancer | Fungal infections |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | n/a | $0.910 per capsule 100 mg capsule |
| 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