Why have most medications never been properly tested on kids?
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.