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COPYRIGHT 2005 All rights reserved. Reproduced by permission of The Condé Nast Publications Inc.
Not long ago, a three-year-old boy fell off a jungle gym in Boston and lacerated his cheek. His parents rushed him to the emergency room of a nearby hospital. A nurse restrained the screaming boy while a surgeon cleaned his cheek and injected it with a small dose of bupivacaine, a local anesthetic that is widely used in adults. When the surgeon began to suture the wound, the child had a seizure and his blood pressure suddenly dropped; he was on the verge of going into shock. He was transferred to the intensive-care unit, where doctors tried to account for his symptoms. A cat scan taken to see if the fall had caused cerebral hemorrhage showed no evidence of brain damage.
Maureen Strafford, a pediatric anesthesiologist and cardiologist, was paged to assist, and she found that the level of bupivacaine in the boy's blood was perilously high. The boy was intubated and placed on a respirator. He spent several days in intensive care before recovering from the overdose.
The package insert for bupivacaine does not provide specific dosing information for children; the E.R. surgeon had adjusted for the boy's weight by "dosing down" from the amount recommended for adults. But such extrapolations cannot account for the differences in the biology of children. Even growing teen-agers who weigh as much as adults tend to absorb and metabolize medicine more quickly than adults, since organs that break down drugs, such as the liver, or excrete chemicals, such as the kidneys, take years to mature. The rate of blood flow to the skin and lungs is also higher in children, so topical or inhaled agents may be more rapidly absorbed.
Strafford told me that the surgeon's decision to improvise with bupivacaine was not unusual. Although the Food and Drug Administration has long required that medications be screened for safety in adults, approximately seventy-five per cent of drugs approved for use in the United States have never been subjected to comprehensive pediatric studies. A physician, however, is allowed to use any F.D.A.-approved drug in whatever way he deems beneficial, and he isn't required to inform parents if it hasn't been specifically tested on children. There is no single official repository of information about how to calibrate drug dosages for children. Since pharmaceutical companies rarely collect data about the effects of their drugs on minors, there is scant information about pediatric dosing in the Physicians' Desk Reference, a compendium of guidelines and warnings supplied by drug companies; pediatric handbooks are published by private companies, but they are not comprehensive and their data are not obtained through a consistent methodology. In the absence of reliable information, doctors are frequently forced to engage in guesswork when administering drugs. Speaking of the three-year-old boy, Strafford said, "This is a perfect example of what can happen to a healthy kid."
I recently spoke with Ellis Neufeld, a pediatric hematologist at Children's Hospital Boston, who has begun to document the different ways children react to Lovenox, an anticoagulant that has been safely used in adults. A teen-ager at the hospital, he said, had recently developed a severe brain hemorrhage after taking the drug; emergency neurosurgery was required to save his life. This spring, Neufeld completed a preliminary study of thirty children who had been placed on closely monitored regimens of Lovenox. The findings helped him formulate a set of target doses in pediatric patients, adjusting for variables such as kidney function. (In very young children, the renal system is not fully developed.) His results will be ready for publication in several months. In Neufeld's view, such a study should have been required by the F.D.A. before Lovenox was approved for use in children. "The package insert from the drug company does not provide a doctor with what he needs to know," he said. Under the rubric "Pediatric Use," the insert merely states, "Safety and effectiveness of Lovenox Injection in pediatric patients have not been established."
Children with certain illnesses can be especially sensitive to the side effects of a drug. For example, infants with meningitis are much more likely than adults to react poorly to chloramphenicol, an antibiotic that is a...
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