How come I did not know that? Pharmacogenomics, Pharmacy Consultants, and Adverse Drug Events
In My Own Words
by Dan Osterweil MD, FACP, CMD
CALTCM CEO and Past-President

A recent article in the WSJ (95% of people have genetic variations that affect if a drug will work for them or not points out an important phenomenon of gene variation and its effect on drug metabolism. The article points to variations in enzyme activity that impact clearance of various drug classes. While in many instances the variation has minimal clinical relevance, in selected cases, such as multiple drug use, lack of effect of certain medications used concomitantly with others or in smokers, there may be adverse effects or lack of effect. 

The question raised by the article is whether all patients should undergo genetic screening to avoid such outcomes. Experts argue that since the tests are very expensive, they should be used only when clinically indicated and when usual manipulation of drug dose fail.  In my own experience, I have been faced with dilemmas such as agitation in a demented elder that was produced by the uncommon but known interaction between Donepezil (an Alzheimer's medication), an antidepressant (SSRI) and an over-the-counter St. John's Wort. The syndrome is labeled "serotonin syndrome" and it is produced when several medications such as those described use a common enzyme pathway (CYP2D6). It creates a higher serum concentration of one medication, in this case the SSRI, producing a reaction manifested clinically by restlessness and face flushing. Clinicians versed in managing such medications could either stop one of the medications or reduce the dose of the SSRI rather than add another drug to manage "agitation".

This points out the critical importance of drug reconciliation at the time of SNF admission. This should not be merely a paperwork activity, but rather a thoughtful review of drugs, their indications, dosage and frequency as well as drug-drug interaction and food-drug interactions. In the pressure to produce, the important role of the pharmacy consultant cannot be stressed enough. Pharmacy consultants need to focus on the important issues of patient safety and avoiding adverse drug reaction. In my opinion, in an ideal world every new nursing home admission should have a drug regimen review by the Pharmacy consultant within a given time, preferably 24-48hrs, instead of the current mandate of once every 30 days.  Physicians and facilities may request an expedited review at an additional cost with many of the dispensing pharmacies, and in complex regimens this may be an advisable path to take.