In the wake of a Sept. 10 "Dear Doctor" letter from Cephalon (NASDAQ:CEPH) to health-care practitioners, the FDA has issued a press release and a public health advisory of the dangers of misusing the company's pain drug Fentora.

Fentora was approved for marketing last year as a treatment for patients with breakthrough (read intense) cancer pain. Following the deaths of several patients who took the drug either for non-prescribed uses or at the wrong dose, the FDA has asked Cephalon to "strengthen warnings and improve the dosing instructions in the drug's product labeling" on Fentora.

The FDA is under constant criticism -- usually misguided, in my opinion -- for its monitoring of drug safety. Sometimes critics call for the agency to be stricter on drug safety monitoring, as with GlaxoSmithKline's (NYSE:GSK) Avandia, while other times they urge it to be less strict, as with Dendreon's (NASDAQ:DNDN) lead drug Provenge.

Caught between these two rocks and a hard place -- congressional oversight -- the agency sometimes takes a schizophrenic approach to monitoring drug-adverse events. The Sept. 26 press release and advisory the FDA put out about Fentora doesn't include any information that Cephalon didn't mention in its "Dear Doctor" letter.

The FDA's release stated that "it is dangerous to use Fentora for any short-term pain such as headaches or migraines," and that "it is critical to follow product labeling" when using the drug. With the extra label warnings promised by Cephalon, the FDA's goal with this release may be to make the agency seem that it's taking charge in monitoring patient safety. 

Sales of Fentora totaled $68 million in the first two quarters of 2007 and account for less than 8% of Cephalon's total sales for the first half of the year. Any off-label Fentora sales damage was already done to Cephalon with its Sept. 10 letter, so the FDA press release and advisory won't likely have much additional impact on Cephalon's top line.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. No warning letters have been issued on the Fool's disclosure policy.