DNA Testing Flags Risky Drugs

To help patients who can't handle taking certain drugs, researchers have developed a simple test that collects DNA code, reports CBS News Correspondent Elizabeth Kaledin.

Approximately two million people are hospitalized each year for drug reactions and nearly 100,000 die. Now doctors are paying more attention to the fact that nearly thirty percent of the population may be taking drugs their genetic makeup can't handle.

Some of the most commonly prescribed medicines found ineffective because of genetic roadblocks are codeine, Prozac, Lopressor for high blood pressure and tacrine for Alzheimer's disease.

Claire Jacobi has dreaded taking medicine all her life because she suffers bad reactions to even the most common drugs. She nearly died after taking codeine under her doctor's orders.

"I was just fighting for my life," she says. "I told my surgeon I thought the medicine was poisoning me, and five years later I found out I was right."

Claire's DNA contains a slight variation which won't let her body process drugs. When she took the codeine she got no pain relief, and the drug built up to potentially toxic levels.

"I think for many years we thought everybody would respond the same to a medication, and over the years we've learned that's just not true," says Dr. Raymond Woosley of the Georgetown University Medical Center.

Dr. Woosley is a pioneer in pharmacogenetics, a field focused on predicting which drugs will work on an individual by analyzing their genes.

Cells containing genetic code are collected from the inside of the mouth, then analyzed on a tiny DNA Identification card known as a DNA chip. The test takes only a few hours and the DNA sample can be stored for future analysis.

Georgetown's Dr. David Flockhart predicts that in the future it may possible for everyone to have their own DNA chip.

"This opens up the whole possibility of an era of personalized medicine, where because of one's specific genetic characteristics you'll get a particular drug," Flockhart says.

The science of pharmacogenetics is still in its infancy and won't become mainstream until the DNA test has government approval. Doctors believe just knowing that our genes determine which drugs will succeed is a prescription for major advances in medicine.