gefitinib

gefitinib,

an antineoplastic.

indication This drug is used to treat non-small cell lung cancer.

contraindications Pregnancy and known hypersensitivity to this drug prohibit its use.

adverse effects Adverse effects of this drug include nausea, diarrhea, vomiting, anorexia, mouth ulceration, rash, pruritus, acne, dry skin, cough, dyspnea, peripheral edema, amblyopia, conjunctivitis, eye pain, corneal erosion, and ulcer. Life-threatening side effects include pancreatitis, toxic epidermal neurolysis, angioedema, and interstitial lung disease.

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gefitinib Warning - High-alert drug!

Iressa

Pharmacologic class: Epidermal growth factor receptor inhibitor

Therapeutic class: Antineoplastic

Pregnancy risk category D

Action

Unclear. Inhibits tyrosine kinase action, which inhibits cell growth and reproduction. May also inhibit angiogenesis in tumor cells.

Availability

Tablets: 250 mg

⊘Indications and dosages

➣ Locally advanced or metastatic non-small-cell lung cancer after failure of platinum-based and docetaxel chemotherapy

Adults: 250 mg P.O. daily

Dosage adjustment

• Patients with diarrhea or skin reactions, pulmonary symptoms, or ocular symptoms
• Patients taking CYP3A4 inducers concurrently

Contraindications

• Severe hypersensitivity to drug or its components

Precautions

Use cautiously in:
• hepatic impairment or hepatotoxicity
• pregnant or breastfeeding patients
• children.

Administration

• Give with or without food.

Route	Onset	Peak	Duration
P.O.	Unknown	3-7 hr	Unknown

Adverse reactions

CNS: asthenia

EENT: amblyopia, conjunctivitis, eye pain and corneal ulcer

GI: diarrhea, nausea, vomiting, mouth ulcers, anorexia

Respiratory: dyspnea, interstitial lung disease

Skin: acne, rash, dry skin, pruritus, vesiculobullous rash

Other: peripheral edema, weight loss

Interactions

Drug-drug. Histamine₂-receptor antagonists (such as cimetidine, ranitidine), phenytoin, rifampin: decreased gefitinib blood level

Itraconazole, ketoconazole: increased gefitinib blood level

Metoprolol: increased metoprolol exposure

Warfarin: increased International Normalized Ratio (INR), increased bleeding events

Drug-diagnostic tests. Alkaline phosphatase, bilirubin, hepatic enzymes: increased levels

Patient monitoring

• Monitor INR and watch for signs and symptoms of bleeding if patient is also receiving warfarin.
• Monitor liver function test results.
☞ Watch for dehydration if patient has severe or persistent diarrhea, anorexia, nausea, or vomiting.
☞ If patient experiences worsening pulmonary symptoms, severe diarrhea, skin reactions, or ocular symptoms, expect to stop therapy until cause is determined or problems resolve.
☞ Discontinue therapy if interstitial lung disease is confirmed.

Patient teaching

• Tell patient to take with or without food.
☞ Instruct patient to immediately report severe or persistent diarrhea, anorexia, nausea, vomiting, increased shortness of breath or cough, eye irritation, or new symptoms.
• Caution female of childbearing age not to become pregnant.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.