A Cure Worse than the Disease
Usually, medications cause only mild side effects, such as drowsiness, headaches, or nausea. Occasionally, patients are allergic to medicines and break out in hives or go into shock. But sometimes reactions to drugs are more serious. In the United States, about 2.2 million patients per year are hospitalized because of adverse drug reactions, and more than 100,000 die. No doctor intends for a drug’s side effects to be worse than the disease it is meant to cure. Nonetheless, the current process of prescribing drugs based on medical and family history is one of trial and error.
An emerging field called pharmacogenomics is revolutionizing the prescription process. Pharmacogenomics is the study of how genetic variations can cause different people to react in different ways to the same drugs. In most cases, for example, genetics determines the way in which—and the speed at which—a person’s body breaks down a medication. If a person’s body metabolizes a drug too quickly, the drug may not be effective. If the drug is metabolized too slowly, a standard dose may be too much.
In the future, a patient in need of a prescription could have a blood test, and health care workers could run the blood test results through a computer using biochip, or microarray, technology. In hours, a doctor could have enough information about a patient’s genetic background to predict how the person would respond to a certain drug and decide whether to adjust the dose. Individuals may even be able to have their genomes mapped and put onto cards to take to doctor visits. Biochip technology is not yet available in most doctors’ offices, but many drugs are already being labeled with pharmacogenomic information advising doctors that patients with certain genetic variations may need a lower or higher dose of the medication.
While pharmacogenomics can provide doctors with more information about their patients, gene therapy may someday provide them with another tool. Some diseases, such as Alzheimer’s or hemophilia, have a strong genetic basis. Doctors are beginning clinical trials in which they treat Alzheimer’s by injecting genes, during surgery, into the area of the brain that has the most affected brain cells. The new genes will instruct brain cells to make more of a protein that keeps nerve cells alive longer.
Doctors are also beginning to treat hemophilia using gene therapy. One method is to inject genes into the liver. In other clinical trials, new DNA is inserted into a virus that can then be used to “infect” a patient’s diseased cells. The field of gene therapy is developing slowly because it requires researchers to accomplish several feats. First, they must engineer, and test, a gene that is safe to insert into humans. Then they must find a way to get the gene to the part of the body that needs it—often using nanotechnology. Much of this research is still being done in animals, but there have been a few successful gene therapy trials in humans.