Pharmacogenomics and practical applications

The next decade will see a significant increase in the rate of practical applications for pharmacogenomics becoming available, and pharmacists will play a critical role in helping them benefit the patient, says a key expert in the field.

"The day is going to come in the not too distant future...where our patients will either arrive with not just a few SNPs in genes that are important for drug metabolism, but will have their entire genome sequenced, or will want their entire genome sequenced," Richard Weinshilboum, MD, professor at the Mayo Clinic College of Medicine, told Drug Topics. He was guest lecturer at a recent National Institutes of Health event.

"When you scan across the whole genome, you find all kinds of things that we have never anticipated that will play a role in drug response," he said.

The National Institute of General Medical Sciences and the National Human Genome Research Institute are working to bring this kind of information to the bedside, Weinshilboum said.

The best source for the currently known connections is the FDA's website on pharmacogenomic biomarkers in drug labels, but he said there are still challenges with using that current information.

For example, if the genotype of cytochrome P450 2C19 is in a patient's medical record, providers can be aware if the patient is a poor metabolizer of clopidogrel, he explained. FDA already has a black box warning about the issue. If a middle-aged male who is a known poor metabolizer arrives in the cardiac cath lab on a Saturday night with chest pains, Weinshilboum said, "you would want the pharmacist to make that information available to the cardiologist in the cath lab," before the use of the bolus of clopidogrel.

"We are going to have that information in the electronic medical record and probably there will be alerts of various sorts that will have to come from the pharmacy or from some organization within the institution," he said. "Certainly all of us are thinking that our pharmacy and therapeutics committees will play critical roles in deciding what goes in the medical record, how to make that available to the physician when he or she writes an order, and how to ensure that we don't alarm anyone, and we do it in a fashion that is user-friendly and intelligible."