ImClone Systems and Bristol Myers Squibb informed health care providers on September 13, 2005 about two new warnings added to the label for Erbitux© (cetuximab):
* **Longer observation times after infusion** Because some patients have experienced allergic reactions during and after Erbitux infusion, the following was added to the label: *A 1-hour observation period is recommended following the ERBITUX infusion. Longer observation periods may be required for patients who experience infusion reactions.*
* **Laboratory tests for low magnesium levels** Patients should be monitored for low magnesium levels and accompanying low calcium and potassium levels during treatment with Erbitux and for approximately 8 weeks after treatment ends.
About half of patients in clinical trials experienced low magnesium levels, 10 to 15% had severely depleted levels. Onset of low magenesium levels occured within days to months after beginning treatment and can be a risk after for several weeks after treatment ends.
[Dear Health Professional Letter from ImClone and Bristol Myers Squibb](http://www.fda.gov/medwatch/safety/2005/Erbitux_91405_dearhcp.pdf)
[FDA Medwatch changes to the Erbitux label](http://www.fda.gov/medwatch/safety/2005/Cetuximab_91405_PI.pdf)
[Associated Press story about the changes](http://news.yahoo.com/s/ap/20050915/ap_on_he_me/cancer_drugs)
March 02, 2007 at 3:25 am, Frank M Polack MD said:
On Erbitux for colon Ca. Third dose one month ago. My Magnesium is very low and I need injections every 2-3 days. My oncologist is not certain if I should continue with Erb. with the low levels of Mg. My questions is: What information is available as far as additional bad effects of using Erb. before Mg recovers,
How long does it take to recover a normal Mg level after being off the drug for several weeks? Thank you
April 23, 2007 at 11:03 pm, Frances Chen said:
How long after you stop Erbitux will rash go away?