gefitinib, (Iressa discontinued in the US) (cont.)

Pharmacy Author:
Medical and Pharmacy Editor:

SIDE EFFECTS: About one in one hundred persons receiving gefitinib develop a potentially serious lung condition called interstitial lung disease that causes inflammation within the lung. Therefore, patients taking gefitinib who develop new or worsening cough, fever, or difficulty in breathing should contact their physician immediately.

Eye irritation has been observed in patients receiving gefitinib, and patients who develop the onset of new eye symptoms should contact their physician.

All patients taking gefitinib should seek medical advice promptly if they develop severe or persistent

PRESCRIPTION: Yes.

GENERIC AVAILABLE: No.

PREPARATIONS: Clear capsules of 50 mg.

STORAGE: Capsules should be stored at room temperature, 15-30 C (59-86 F).

DOSING: Gefitinib is taken by mouth. The dose is 250 mg once daily. The dose is the same for men or women of any age or weight, and gefitinib can be taken with or without food.

DRUG INTERACTIONS: Gefitinib may increase the blood-thinning effects of warfarin (Coumadin) and increase the risk of bleeding. Therefore, patients receiving gefitinib and warfarin at the same time should have more frequent testing of the "thinness" of their blood.

Patients who receive drugs that increase an enzyme in the liver called CYP 3A4 that destroys gefitinib (for example, rifampin or phenytoin (Dilantin) may need a higher dose of gefitinib to maintain the effectiveness of gefitinib.

Similarly, patients who receive drugs that reduce CYP 3A4, for example, ketoconazole (Nizoral), itraconazole (Sporanox), fluconazole (Diflucan), erythromycin, clarithromycin (Biaxin), ritonavir (Norvir), nelfinavir (Viracept), indinavir (Crixivan), nefazodone (Serzone), as well as grapefruit juice, may need a lower dose of gefitinib to prevent side effects from increased levels of gefitinib.

Medically Reviewed by a Doctor on 7/9/2015


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