Indeed, bodies handle drugs differently at different ages. Studies aren't just for sick kids. Say your child is prone to hay fever but is not sniffling today. She'd be a candidate to swallow one dose of an adult antihistamine and have blood samples drawn to check metabolism, thus confirming the right dose. These dosing studies require spending up to a day in a clinic, giving blood and a small side-effect risk, in hopes doctors can improve treatment of future patients.
Longer studies are usually for sick kids, and sometimes involve a placebo.
Take the inhaled antibiotic Tobi, approved to treat a lung infection in cystic fibrosis patients at least six years old. Taking Tobi before age six might ward off the infection instead of just treating it, but it also might be dangerous. Comparing Tobi with a dummy pill in babies and preschoolers is the only way to know, but some parents find that a tough choice, says Dr. Pamela Zeitlin of Baltimore's Johns Hopkins University. Kearns spends up to an hour discussing a study before ever handing parents a consent form, which should explain risks in laymen's terms. University-based research, particularly at pediatric specialty centres, may get more careful oversight.