The FDA has received reports of 12 cases of acute liver failure, including the four deaths, in patients treated with Ketek. FDA safety evaluators also uncovered 23 other cases where patients suffered serious liver injuries after receiving the antibiotic, which is formally called telithromycin.

The FDA consider restricting the use of Ketek, or even withdrawing it. The liver failure should rate rise to levels seen in another antibiotic, Trovan, before its use was restricted in 1999.

It cannot be determined whether the drug's risk is currently higher than that posed by any other of the various antibiotics associated with liver problems.

FDA spokeswoman Susan Bro said it would be "premature" to discuss any steps the agency might take. The current FDA-approved label for Ketek warns of liver disfunction that can be severe but is "usually reversible."
In January, the Annals of Internal Medicine published a report detailing three cases of severe liver problems, including one death, in patients at a North Carolina hospital after they began taking Ketek.

Congress is investigating how the FDA has handled Ketek, including problems with a clinical trial that was supposed to show the drug's safety.
Irregularities in the execution of that trial left the FDA unable to make a "meaningful assessment" of liver safety concerns associated with the drug, according to the memo.