Scientists are increasingly turning to a patient's own DNA as a clue to whether certain medications may cause dangerous physical or behavioral responses, the Wall Street Journal
The concept is the latest example of personalized medicine — tailoring treatment to patients based on their genetic makeup. Although it is usually used to determine which patients may respond best to which drug, its use in predicting bad reactions is also gaining traction.
"Drug prescribing is still relatively rudimentary," said Kathryn Phillips, professor and director of the University of California-San Francisco Center for Translational and Policy Research on Personalized Medicine. "We look at somebody's weight and maybe their gender. Certainly I think in the future we'll see that people get genotyped and they'll have this whole list of drugs that they should avoid."
Progress is being made toward this goal on a number of fronts:
- The Max Planck Institute of Psychiatry in Munich is looking for genetic markers have identified about 100 that might indicate increased risk of suicidal thoughts from antidepressant drugs.
- Other scientists are studying which patients develop dangerously low white blood cell counts while taking antipsychotic drugs.
- Researchers are also investigating whether genetics can help detect adverse reactions to vaccines and some cancer treatments.
Identifying who might be susceptible to a bad reaction from a medicine may be easier than figuring out who will do well, experts told the Journal. That's because the effectiveness of a medication depends on a many processes, but a side effect could arise from an alteration of a small number of genes or even a single one.
For instance, a mutation of the HLA gene has been found to greatly increase the risk of getting a potentially deadly skin reaction called Stevens Johnson syndrome in patients taking carbamazepine, an anticonvulsant drug.
In 2007, the Food and Drug Administration issued an alert about the risks and recommended that patients of Asian ancestry, for whom the gene defect is more common, be screened before taking carbamazepine.