Cephalon Inc has sent letters and warned doctors about deaths linked to its Fentora pain drug for cancer patients, U.S. media reported Friday.

According to Cephalon, there were four deaths involving two headache patients prescribed a powerful painkiller as a headache treatment, one suicide and a patient administered the drug outside the recommended dosing. 

In the letter posted on the U. S. Food and Drug Administration website, the company said it had become aware of "serious adverse events, including deaths" in patients being treated with the drug Fentora.  

However, the company said the deaths were the result of improper dosing, improper product substitution as well as using the drug in patients who can't tolerate opiods.

"None of the reports were in cancer patients, which leads us to believe they were inappropriate candidates for the product," Cephalon spokeswoman Candace Steele said.

The company said the drug should only be used for cancer patients already on other opiod drugs such as morphine or another type of fentanyl product. Fentora, also a fentanyl product, is indicated for use in treating breakthrough cancer pain.

The letter also said Fentora shouldn't be used to treat post-operative pain, acute pain.

Fentora's label is now being updated to instruct doctors more clearly on how to properly use the drug, which is meant for cancer patients who are already on around-the-clock medicine for pain.

Doctors have written about 78,000 prescriptions for Fentora tablets since October, said Cephalon.

(Agencies via Xinhuanet.com September 14, 2007)