Cephalon says believes there were 3 Fentora deaths

BOSTON (Reuters) - A Cephalon Inc spokeswoman said on Thursday she believed there had been three deaths related to the company's pain drug Fentora since the summer, most likely due to respiratory failure.

Earlier on Thursday, the U.S. Food and Drug Administration said Cephalon had sent a letter to doctors warning of serious adverse events associated with Fentora if it is not used correctly.

"The company is concerned that these medications may have been inappropriately prescribed," Steele said. "What we know is that there appears some patients who were not taking it for the indication for which it is approved, which is breakthrough pain in cancer patients."

Steele said patients who take Fentora must already be taking a regime of other opioid painkillers to such an extent that their bodies have become used to, or tolerant of, the drugs.

Steele said the company notified the FDA immediately.

Respiratory failure is a danger if patients are not already tolerant to opioids, she said, and therefore should not be given to patients with acute pain.