Saunders, Hollie

Abstract Older patients often have multiple medical issues which predisposes them to complications of polypharmacy and medication interactions. We present a case of an 89-year-old female who presented to the emergency department after a fall. An electrocardiogram (ECG) showed a junctional bradycardia with a ventricular rate of 50 beats per minute (BPM). Her magnesium was 3.5 mg/dl (1.7–2.3 mg/dl). She had recently increased her milk of magnesia use for constipation. Pertinent other medications included verapamil 280 mg daily. On admission 2 grams of calcium gluconate IV were administered and the verapamil was held. An ECG the next morning showed sinus rhythm with a ventricular rate of 76 BPM.

Abstract Pharmacogenomics describes the link between the genetic code and variations in drug response or adverse effects. It is rapidly gaining in both interest and accessibility. The knowledge of the gene-drug pairing for a wide range of medications will allow the clinician to select drugs with the best efficacy, appropriate dose and lowest likelihood of serious side effects. In order to apply this knowledge, practitioners need to be familiar with the basic principles of pharmacodynamics and pharmacokinetics and how these relate to drug response. Once these are understood, so can be the genetic variations that lead to different phenotypes. Our review explains these concepts and uses examples of commonly prescribed medications and their gene pairings. At the present time, the Food and Drug Administration (FDA) guidelines remain sparse in regards to pharmacogenomic testing but, despite this, direct-to-consumer testing is widely available. In this context, we detail how to interpret a pharmacogenomic report, we review the indications for testing, as well as its limitations. This information is a step ahead towards invidualized medicine, in the hope that tailoring medications and doses to an individual’s genetic make-up will predict a safe and effective response.