FDA Public Health Advisory

Biogen Idec and U.S. regulatory officials have issued a warning to doctors stating that Avonex can cause liver damage and liver failure. The warning, which is in a letter posted on the Food and Drug Administration's (FDA) website, says, "In post-marketing experience, severe hepatic injury, including cases of hepatic failure, has been reported rarely in patients taking Avonex."

Revisions to the warnings, adverse reactions, and post-marketing experience sections of a medication are not unusual. According to Amy Ryan, a spokeswoman from Biogen, this warning is "an ordinary change made to the drug's packaging."

Biogen Idec noticed an increased incidence of liver injury and liver failure and initiated talks with the FDA about modifying its prescribing guide "a few months ago." According to Ryan, the interest in liver complications is a current concern of the FDA.

To learn more, visit http://www.fda.gov/medwatch