A painkiller banned in the United States two decades ago because of potentially fatal side effects is still being sold here, often to Hispanic immigrants who are unaware of the danger, researchers said.
Metamizole, or dipyrone, is a fever and pain reliever sometimes called "Mexican aspirin." It was removed from the U.S. market in 1979 by the Food and Drug Administration but is available without a prescription in Mexico, other Latin American countries, parts of Asia and Africa.
Writing in the June edition of the journal Pediatrics, University of Utah researchers said that Spanish- or Portuguese-speaking parents of children evaluated in a University of Utah clinic last fall were interviewed, and more than a third of those surveyed said they had used metamizole.
Of those who used it, one-fourth said they had bought it in the United States, researchers said.
The drug's most serious side effect is a reduction in disease-fighting white blood cells, making the person susceptible to life-threatening infections.
The study was sparked by the case of a 4-year-old boy taken to the emergency room at Primary Children's Hospital who had a fever and trouble walking because of what turned out to be a serious infection in his hip.
Because he had a low white blood cell count, the boy was checked for leukemia. It was then that study co-author Dr. Carrie Byington, associate professor of pediatrics at the University of Utah's School of Medicine, asked about whether the child had been given metamizole.
The boy's mother said she gave it to her son and had also taken it herself. The mother had been hospitalized with a serious infection five months before her son; in fact she had nearly died, medical records showed.
"Hers was life-threatening. She was at the point of death when she was admitted to the emergency room. Every organ was affected," Byington said.
The mother said she purchased the drug at a Latin American market in Salt Lake City. Byington said they sent Spanish-speaking members of their staff to the market, and they were able to purchase the medication for $9 to $11.
"It's more expensive than Tylenol, but they're here in a strange country. Their child gets sick or they get sick and they'll look for what they recognize," she said.
"It's a very effective pain reliever and fever reducer. Parents invariably tell us it works much better than Tylenol," said Byington.
Byington said not everyone experiences the extreme side effects, but "we don't want people to be taking a medication that could have life-threatening side effects for a headache or a fever."
The drug has been banned so long in the United States that many doctors here haven't been taught about it in medical school, she said.