WASHINGTON (Reuters) - In the 1960s, several newborn babies died after being given an adult antibiotic that their livers could not break down, proving that, when it comes to medicine, children are not just ``little adults.''

Despite that lesson four decades ago, pediatricians remain in the dark about how most medicines affect their patients. Only about a fourth of all drugs have been tested in children, leaving doctors at times guessing at the best treatments.

``That has left the medical community that cares for children in a very difficult situation,'' said Dr. Ralph Kauffman of Children's Mercy Hospital in Kansas City. ``We either have to deny children useful medicines or we have to give them medicines without adequate prescribing information.''

But new data is coming in thanks to incentives begun two years ago and a federal measure that took effect this month, which have sent companies scrambling to do pediatric studies.

Under the program created by Congress, drugmakers can gain an extra 6 months of market exclusivity before generic competitors hit the market for each product they study in children. That extra time can mean hundreds of millions of dollars in added revenue for a single drug.

``The interest in developing the type of trials that need to be done has been pretty phenomenal,'' Dr. Dianne Murphy, associate director of pediatrics at the US Food and Drug Administration (news - web sites) (FDA) drug evaluation center, said in an interview. ``The important thing is you can't just do any study. FDA determines if there is to be a public health benefit.''

So far, drugmakers have proposed about 200 pediatric studies for medications for AIDS (news - web sites), allergies, asthma, depression and nearly every other ailment that afflicts children. The research could involve more than 20,000 children, from newborns to adolescents. By contrast, only 11 studies on children were done from 1991 to 1997, Murphy said.

And starting this month, a federal rule gives the FDA power to require pediatric studies for drugs that might benefit children. Regulators want to know what doses work best for children and whether some drugs might produce unexpected reactions when they interact with kids' immature organs and different bodily systems.

The goal is information to add to labeling instructions for pediatricians and parents, and officials hope about 100 products will have new directions within the next two to three years.

Challenges For Studying Kids

Doing research with children is not easy. Companies used to working with adult volunteers need to find researchers with the expertise to help run pediatric studies and address their unique challenges.

For years, people worried that using children as guinea pigs was unethical. But Dr. Robert Ward, professor of pediatrics at the University of Utah, said he views that as largely settled.

``We are treating children with less than optimal information about effectiveness, dosing and safety. You just have to ask yourself: What is more unethical? To treat a child in that situation or to treat a child in part of a controlled clinical trial?'' Ward said.

Doctors still must work to convince parents to expose their children to unknown risks and subject the kids to blood and other tests they normally may not need. The pool for recruits is small because there are fewer sick children than adults.

In addition, getting children to cooperate can be tough. Younger ones may have trouble swallowing pills or may not take a medicine because it tastes bad. In those cases, researchers need to develop kid-friendly formulations. Equipment must be scaled down and tests redesigned to analyze smaller samples.

``You can't draw a bucket of blood from babies,'' Kauffman noted.

And how do you ask very young children to describe pain? Researchers need to find new measurements of whether medicines are working. Also, to minimize any fear of going to see a doctor, some research centers are being revamped with bright colors, games and activities to make the experience fun.

Efforts to adjust infrastructure and science to the needs of children has produced what the FDA's Murphy calls the ``NASA (news - web sites) effect,'' comparing it to the vast scientific knowledge gained when the United States decided to explore space and the moon and poured resources into developing the needed technology.

``Here we have a population (of children) that hasn't been studied, and we are realizing we have these large scientific gaps'' to fill in, she said.

But the advances come with a price. While brand-name drug makers gain revenue, consumers pay higher prices for six months longer without a generic alternative for such popular drugs as allergy medicine Claritin and antidepressant Prozac.

Generic drugmakers say they will press for modifications to the incentives program when Congress considers whether to reauthorize it next year. While helping children, the current system can come at the expense of elderly or chronically ill patients with high medical bills, generic companies argue.

But Ward believes society owes it to children to make up for decades of neglect while adults reaped major benefits from medical advances. ``I view that (cost) as paying the debt the country accumulated,'' he said.

(From Yahoo)