Erbitux Disease Interactions

The use of certain EGFR inhibitors has been associated with progressive decreases in serum magnesium levels leading to severe cases of hypomagnesemia and accompanying electrolyte abnormalities, including hypocalcemia, and hypokalemia. The onset of hypomagnesemia and accompanying electrolyte abnormalities occurred days to months after initiation of these agents. Periodically monitor patients for hypomagnesemia, hypocalcemia, and hypokalemia, during and for at least 8 weeks following the completion of therapy. Caution is recommended when using these agents in patients predisposed to electrolyte imbalances and those with a history of coronary artery disease, congestive heart failure, or arrhythmias. Replete magnesium and other electrolytes as appropriate.

Cutaneous reactions, in some cases severe, have been reported with the use of EGFR inhibitors. Monitor patients who develop dermatologic or soft tissue toxicities while receiving these agents for the development of inflammatory or infectious sequelae. It is recommended to withhold treatment, and appropriate measures should be instituted as appropriate or discontinue the use of these agents for dermatologic or soft tissue toxicity associated with severe or life-threatening inflammatory or infectious complications. Advise patients to wear sunscreen and hats and limit sun exposure while receiving therapy with these agents as exposure to sunlight can exacerbate dermatologic toxicities.

Some epidermal growth factor receptor (EGFR) inhibitors should be administered cautiously in patients with ocular disorders such as primary keratitis, ulcerative keratitis, or conjunctivitis. It is recommended to interrupt or discontinue treatment with these agents if patients present with acute or worsening ocular disorders.

The use of certain EGFR inhibitors has been associated with pulmonary toxicity. Serious cases of interstitial lung disease (ILD), including fatal cases and interstitial pneumonitis or pulmonary fibrosis have been reported. Caution is recommended when using these agents in patients with a history of interstitial pneumonitis or pulmonary fibrosis or those patients presenting with acute onset of new or progressive unexplained pulmonary symptoms such as dyspnea, cough, and fever pending diagnostic evaluation. If ILD is confirmed, permanently discontinue these agents and institute appropriate measures.

QT prolongation was observed in patients treated with certain EGFR inhibitors. These agents should be administered with caution in patients with congenital long QTc syndrome, congestive heart failure, electrolyte abnormalities, or those who are taking medications known to prolong the QTc interval. Serum electrolytes should be corrected prior to initiating therapy with these agents. Periodic monitoring of ECGs and electrolytes is recommended in these patients. Permanently discontinue the use of these agents in patients who develop QTc interval prolongation with signs/symptoms of life-threatening arrhythmia.

In clinical studies, renal failure occurred in 1% of patients with colorectal cancer treated with cetuximab. Close monitoring is recommended in these patients.