PRECAUTIONS: Before using this medication, tell your doctor or pharmacist your medical history, especially of: lung disease (e.g., pulmonary fibrosis), severe kidney disease, any allergies. Gefitinib is not recommended for use during pregnancy. It may cause fetal harm. Consult your doctor for more details. It is not known whether this drug passes into breast milk. Due to the potential risk to the infant, breast-feeding while using gefitinib is not recommended.

DRUG INTERACTIONS: Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription products you may use, especially of: "blood thinners" (warfarin), drugs which reduce stomach acid (e.g., ranitidine, cimetidine, famotidine, omeprazole, lansoprazole, rabeprazole), certain liver enzyme inhibitors (CYP 3A4 inhibitors such as ketoconazole, itraconazole, erythromycin, clarithromycin). Some liver enzyme inducer medications such as rifamycins (e.g., rifampin, rifabutin), St. John's wort or phenytoin will stimulate certain liver enzymes (CYP 3A4). Your dosage of gefitinib may need to be increased if you are using such medications. Consult your doctor or pharmacist for more details. Do not start or stop any medicine without doctor or pharmacist approval.

OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly. Symptoms of overdose may include: severe/persistent diarrhea, severe skin rash.