Sometimes children's bodies process drugs faster than do those of adults, and they actually need a larger dose. They may need more-frequent dosing. And sometimes side effects in children can be unexpected, and severe. When common drugs like antibiotics have been used for decades there is usually plenty of evidence about how they affect children. But in most cases such studies are smaller than FDA-required trials, so if a side effect is rare, it can still take a long time for such a finding to reach the attention of the average pediatrician.
Families struggling with rarer ailments are worse off.
These parents and their doctors have little choice but to try the unproven. Alexandra's doctors first tried Digoxin, aimed at slowing down her racing heart. It was the only heart drug that she has ever been on that has been approved for use in children. After five weeks it failed. In the four years since, the Kibbes and their pediatricians have become drug detectives.