Gefitinib

60 interactions 147 cited references
Also sold as: Iressa Iressa®
About Gefitinib

Gefitinib is used to treat non-small cell lung cancer that has spread to other parts of the body in people with certain types of tumors. Gefitinib is in a class of medications called kinase inhibitors. It works by blocking the action of a certain naturally occurring substance that may be needed to help cancer cells mul… Read the full Gefitinib drug information page →

Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated Aug 9, 2026 · Editorial policy · Data sources

Sources: FDA prescribing information (Structured Product Labeling), the published literature cited in each entry, DDInter 2.0 (a major open-access drug-interaction database), and legacy DrugBank interaction data distributed by the NIH's RxNav service (decommissioned in 2024) — analyzed and reviewed by our pharmacist team. How we build this library →

Most serious with: Typhoid Vaccine Measles Virus Vaccine, Live Smallpox Monkeypox Vaccine Mavorixafor Rubella Virus Vaccine, Live Yellow Fever Vaccine
10 Contraindicated 48 Major 2 Moderate
All (60) Contraindicated (10) Major (48) Moderate (2)

Major

Gefitinib Magaldrate Decreased exposure of gefitinib Details Gefitinib Magnesium Carbonate Decreased exposure of gefitinib Details Gefitinib Magnesium Hydroxide Almacone® (containing Aluminum Hydroxide, Magnesium Hydroxide, Simethicone) Decreased exposure of gefitinib Details Gefitinib Magnesium Oxide Mag-Ox 400 Decreased exposure of gefitinib Details Gefitinib Magnesium Trisilicate Decreased exposure of gefitinib Details Gefitinib Nizatidine Axid® Decreased exposure of gefitinib Details Gefitinib Pantoprazole Protonix Decreased exposure of gefitinib Details Gefitinib Paroxetine Paxil Increased CYP2D6 substrate exposure Details Gefitinib Phenytoin Dilantin Decreased exposure of gefitinib Details Gefitinib Rabeprazole Aciphex Decreased exposure of gefitinib Details Gefitinib Ranitidine Decreased exposure of gefitinib Details Gefitinib Ranolazine Aspruzyo Increased CYP2D6 substrates exposure Details Gefitinib Rifampin Rifadin Decreased exposure of gefitinib Details Gefitinib Rotavirus Vaccine, Live An increased risk of infection by the live vaccine Details Gefitinib Sodium Bicarbonate Alka-Seltzer® Heartburn Decreased exposure of gefitinib Details Gefitinib St John's Wort Decreased exposure of gefitinib Details Gefitinib Tramadol ConZip Increased traMADol exposure and reduced exposure of the active metabolite Details Gefitinib Vinorelbine Navelbine Increased risk of severe myelotoxicity, particularly neutropenia Details

Moderate

Gefitinib Levothyroxine Ermeza Increased risk of hypothyroidism Details Gefitinib Warfarin Coumadin Increased prothrombin time and INR values and an increased risk of bleeding Details

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Educational information only, not medical advice. Always confirm interactions with your pharmacist or prescriber before making any change to your medications.