FDA renews warning for powerful painkiller patch

The government issued a new safety warning Friday for a skin patch containing a potent painkiller that has been implicated in hundreds of deaths, saying the patch poses unique risks that doctors and patients often fail to understand.

The Food and Drug Administration said the widely used fentanyl patch was being wrongly prescribed by doctors and being misused by patients unaware that something as routine as taking a hot shower while wearing the patch could trigger a potentially fatal overdose.

A study published in a medical journal last summer identified fentanyl, a narcotic up to 100 times more powerful than morphine, as the suspect drug in more than 3,500 accidental deaths reported to the FDA from 1998 to 2005. Safety advocates said the agency’s latest warning, which echoes an alert issued in 2005, was too little, too late.

The patch was developed for cancer patients who suffer severe chronic pain and in some cases have trouble swallowing pills. But Dr. Bob Rappaport, head of the FDA division that oversees painkillers, said some doctors had been prescribing the patch to patients who didn’t need such a powerful narcotic -- and in at least one case, even used it to treat headaches.

Patches can be more convenient than pills; the fentanyl patch is designed to deliver the drug at a steady rate for as long as three days, so patients don’t have to take medication several times a day. But there are also drawbacks: A single patch contains a substantially larger quantity of the medication than individual pills; heat and exercise can increase the rate at which the drug is absorbed through the skin.

Rappaport said the FDA had not found such serious problems with other methods of delivering fentanyl, including by injection. “It’s a unique problem with patches because of . . . the way that the drug is delivered to the body and the way that it’s metabolized,” he said. “It’s complicated by the patch formulation.”

The FDA said doctors should not prescribe the patch for patients whose pain was expected to go away, such as those recovering from an operation. The patch should be used only by patients who are in chronic pain and are already safely taking opioid-type drugs.

The agency warned patients to call their doctors if they have trouble breathing, because fentanyl can shut down the respiratory system. It said patients wearing the patch should avoid hot showers and heating pads.

Rappaport said the situation was “very concerning” because such patch-related deaths could easily be prevented.

And adult patients are not the only ones at risk: At least one child has died after applying a parent’s patch.

Not only is the fentanyl patch strong medicine, it is also widely used. About 4.7 million prescriptions were filled in 2006, according to Verispan, a market analysis firm. The patch was introduced in 1990 under the brand name Duragesic by Johnson & Johnson, but generic versions by Mylan Inc. and other manufacturers now dominate the market.

Friday’s advisory reinforced an FDA alert in 2005, which all sides acknowledge did not do enough to reduce the risk to patients. This time, the agency is directing drug makers to issue brochures that explain the dangers in plain language.

That was not enough to satisfy safety advocates who have been tracking problems with the patch for years.

“I think there is more that needs to be done, or else we’re just going to see this [warning] happen again another two years from now,” said Michael Cohen, president of the Institute for Safe Medication Practices. “The deaths are going to continue.” The Pennsylvania group advises hospitals and doctors on how to prevent medication errors.

Cohen has called on the FDA to limit the number of doctors allowed to prescribe the drug. That could be done by requiring physicians to take special instruction in assuring safety.

But the FDA’s Rappaport said such restrictions could prevent some patients who need the medication from getting prescriptions. About 60 million Americans suffer from chronic pain, he said, but only several thousand doctors in the country are certified pain specialists.

Nonetheless, Cohen said, he is worried the FDA’s latest warning won’t register with busy doctors, particularly those who don’t regularly deal with powerful narcotics. He recommended that hospitals, which usually have pain experts on staff, require their specialists to review all prescriptions for the fentanyl patch. Several deaths reported to his group involved patients inappropriately prescribed the patch for pain relief after surgery.

Last summer, a study named fentanyl as the second-deadliest drug in accidental deaths, behind painkiller oxycodone. Analyzing reports to the FDA from 1998 to 2005, researchers identified 3,545 deaths linked to fentanyl. The study looked at all forms of fentanyl, but “the patch was by far the largest contributor,” lead author Thomas J. Moore said in an interview. By comparison, the paper found that Vioxx -- the painkiller whose 2004 withdrawal was the catalyst for safety reforms at the FDA -- was a suspect in 932 deaths.

Rappaport said the FDA did not have a definitive count of deaths caused by the patch and was working to develop one. He suggested the number could be smaller than reported because many patients using the patch were severely ill and could have died from underlying diseases.

Spokesmen for Ortho-McNeil Inc., the subsidiary that makes Duragesic, and for Mylan said the manufacturers supported the FDA’s action.

Greg Panico of Ortho-McNeil said the company’s research indicated that the safety warnings might be working. Reports of unapproved uses of Duragesic have declined significantly since the summer of 2006, he said.

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ricardo.alonso-zaldivar@latimes.com