Allergy drug risk far from certain, experts say

Patients with asthma and allergies called doctors across Tampa Bay Friday, worried as Singulair became the latest blockbuster drug hit by safety questions.

But right now, the biggest safety threat is that asthma patients might stop the drug without talking to their physicians first, some bay area doctors said Friday.

"What I would not want to see is somebody having a flare-up with their asthma and ending up in the E.R. because of (worry about) an event that's very rare," said Dr. Mark Glaum, an allergist/immunologist and assistant professor of medicine and pediatrics at the University of South Florida College of Medicine.

The Food and Drug Administration said Thursday that it is reviewing the safety of Singulair after about three reports of suicides involving Singulair patients. In the past year, the drug's maker, Merck, has told doctors and patients that possible side effects could include tremors, depression, suicidal thinking and anxiety.

However, Merck officials said Friday they had no reports of suicides or suicidal thoughts among more than 11,000 patients in more than 40 company studies. And three reports is a tiny fraction of the 31-million prescriptions written for Singulair last year.

"I don't think the evidence is very persuasive for any kind of problem," said Dr. Richard F. Lockey, head of USF's allergy and immunology division. "If it were … my child on this drug, I wouldn't stop for a second."

Others had more doubts. Dr. James Orlowski, chief of pediatrics and director of pediatric intensive care at University Community Hospital in Tampa, said it bothered him that other Merck drugs, including Vioxx and Vytorin, also have had safety problems in the past few years.

"The sad thing is that Merck's the same company who's been on Vioxx and keeping quiet about the data that they knew on heart attacks," he said. "This company has got, shall we say, some PR problems."

Singulair works by blocking leukotrienes, a body chemical that can cause allergy and asthma symptoms.

In a statement, Merck emphasized that the suicide reports do not show the deaths were caused by Singulair.

The company said that in studies of 7,300 patients, one patient out of 3,900 treated with Singulair attempted suicide, while three did so among the 3,400 treated with other asthma drugs.

With about $3.4-billion in sales last year, Singulair ranked sixth in U.S. drug sales, according to IMS Health, a health care information company. That popularity is reflected at the USF allergy clinic, where Glaum said about 20 percent of the patients have taken it.

Once or twice, Glaum said, he's taken children off the drug.

"I've seen parents think kids are a little more anxious or excitable on it, so we stop, and it goes away," he said.

Glaum said he hasn't seen any serious behavior or emotional effects.

"Up to this point, the safety profile has been very strong," he said. "It probably is a very, very rare event, and there's no evidence of cause and effect at this point."

Still, it worried Orlowski that Merck has updated its safety information four times.

"One of the problems is that drugs are approved on the basis of short studies, but the drugs are intended to be used for a long time," Orlowski said. "This may be the kind of thing where the problems don't surface until the patients are on the drug for years."

But Lockey stressed that the dangers of uncontrolled allergy and, especially, asthma are far more likely and more documented. More than 17,400 Tampa Bay residents were hospitalized with asthma between 2004 and 2006.

"In my opinion, aspirin has the potential for more side effects than Singulair would ever have," Lockey said. "People don't consider the risk of the disease and what the disease causes versus the risk of the medication. … People need to be reassured that we need much more information before we stop" using it.

The FDA review is expected to take at least nine months, a spokeswoman said.

Lisa Greene can be reached at greene@sptimes.com or at (813) 226-3322.

>>fast facts

About Singulair

The medication ranks sixth in U.S. drug sales, with $4.3-billion last year, according to IMS Health. First approved in 1998, it is part of a class of asthma and allergy drugs that includes AstraZeneca's Accolate and Critical Therapeutics's Zyflo.

Allergy drug risk far from certain, experts say 03/28/08 [Last modified: Sunday, March 30, 2008 9:32am]

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