Drug Interaction Alerts: Why Doctors Ignore 90% of Warnings

Drug interaction databases flag millions of potential conflicts daily, but clinicians override roughly 90% of those alerts. This episode explores why — using the specific example of low-dose amitriptyline combined with Lexapro, a combination that triggers red-flag warnings for serotonin syndrome but is routinely prescribed by gastroenterologists for gut issues. We examine how experienced doctors develop clinical judgment that goes beyond database literalism, how pharmacists triage alerts into "phone call tier" interactions versus background noise, and how drug interaction compendia like Micromedex, Lexicomp, and the British National Formulary disagree with each other on severity classifications. The episode also covers how different countries — including Israel — configure their EHR alert thresholds differently, and how the cytochrome P450 enzyme system provides the underlying framework for predicting interactions without a database.