Ep 184 Must Know Drug Interactions in Emergency Medicine

Drug interaction-related morbidity and mortality is highly under-recognized in Emergency Medicine. Patients who present with altered level of awareness, delirium, syncope and falls are often admitted to hospital without a definitive diagnosis; and only later is it recognized that a drug interaction was at play. Thirty percent of ED patients have at least one drug related problem contributing to their ED visit, which includes adverse drug reactions and subtherapeutic dosing. More than 1 in 9 ED visits are due to drug related adverse events, and many of these drug-related adverse events are due to drug interactions which are almost entirely preventable. In this EM Cases podcast Dr. David Juulink, Dr. Walter Himmel and Anton delve into some common presentations that require having drug interactions in the differential diagnosis, which combinations of drugs to avoid when ordering in the ED and when prescribing for outpatient therapy from the ED, high risk patients for drug interactions and the top 3 drug categories to be aware of when it comes to drug interactions... Podcast production, sound design & editing by Anton Helman Written Summary and blog post by Kate Dillon and Ian Beamish, edited by Anton Helman June, 2023 Cite this podcast as: Helman, A. Himmel, W. Juurlink, D. Must Know Drug Interactions in Emergency Medicine. Emergency Medicine Cases. June, 2023. https://emergencymedicinecases.com/drug-interactions-emergency-medicine. Accessed September 17, 2024 Résumés EM CasesFirst, we need to understand the difference between pharmacokinetics and pharmacodynamics All drug interactions can be split into pharmacokinetic and pharmacodynamic interactions. Pharmacokinetics can be thought of simply as what a body does to the drug. Drugs are absorbed, distributed, metabolized, and excreted. Anything that disturbs these processes can change the serum drug level. Pharmacodynamics can be thought of simply as the effect of the drug on the body. For example, the synergistic impact that two drugs might have on prolonging the QT interval. When to consider drug interactions in the differential diagnosis It is easy to say that drug interactions should always be considered in any ED presentation, but this approach is not practical. Although many clinical scenarios could theoretically be explained by drug-drug interactions, some of the ones that we should be particularly wary of, especially if patients are on multiple medications, or have recently had a change/addition of a new medication are: * Syncope/near-Syncope * Delirium/altered LOA * Falls * Any unexplained clinical presentation after initial ED workup Who are high risk patients for drug interactions, and why are they high risk? 1.Older Patients are at high risk for drug interactions Fifteen percent of older patients have adverse drug reactions and 50% of these are preventable. Some of the reasons behind this are that they often are taking more drugs than younger people, they often have comorbidities like renal dysfunction that make drug interactions more likely, if they have cognitive dysfunction they may be more likely to manifest drug-drug interactions, and they are more frail, making them less able to tolerate drug interactions. Drugs that are higher risk for interactions in older patients include: * Drugs that have a narrow therapeutic range including anticoagulants, hypoglycemic agents (sulfonylureas, insulin), digoxin, sedatives,