Have you ever experienced medication side effects? Unfavorable drug reactions are a worry for all clinicians who prescribe medications to treat adults and children, but genomics can play a role in reducing the number of negative side effects for some medications. Scientists now know to look for genetic variation that can explain why different people may respond very differently to the same drug. As medical practitioners have learned more about the human genome, a new field has developed called pharmacogenomics. Simply put, this means using genomics to get “the right dose of the right drug to the right patient at the right time.” Using genetic tests, physicians can better separate individuals who may be harmed by certain drugs from those who may benefit from them.
Your doctor sequences your genome to decide how to treat your high cholesterol. She might find a variant indicating that a commonly used drug would have little effect on reducing your cholesterol levels, but it would increase your risk of heart attack or stroke. Luckily, you would not be given that commonly used drug due to this genomic information. Instead, another drug would be provided to you that lowers your cholesterol without negative side effects.
Using genomics to get “the right dose of the right drug to the right patient at the right time.
This is not a far-fetched scenario. Take, for instance, Ziagen® or abacavir, a commonly prescribed drug therapy for HIV, the virus that causes AIDS. When first used, some patients developed severe rashes, fatigue, and diarrhea – symptoms of a possible immune system reaction. Scientists looked at genomic variants associated with the immune system and finally identified one – called HLA-B*5701 – that causes the overreaction. Now doctors routinely test for the variant to find out who should avoid the drug.
Today, the U.S. Food and Drug Administration (FDA) requires pharmacogenomic information to appear on the labels of 106 medications that are currently on the market. Before the Human Genome Project started, only four drugs carried such a label. As DNA sequencing costs decline and our knowledge increases, tailoring drugs to your genomic profile will become even more common in medical practice.