Faculty Bibliography

Objective: Beta-adrenergic antagonists (BAAs) and calcium channel blockers (CCBs) negatively affect chronotropy and inotropy and are administered for many indications. The frequency of adverse reactions when BAAs and CCBs are administered concomitantly is infrequently described [1]. We reviewed the incidence of hemodynamic instability in patients in whom both a BAA and CCB were administered within a pharmacologically relevant time period.
Method(s): This was a quality improvement initiative in emergency department (ED) patients, performed at an urban, tertiary care hospital network from 1 October 2016 to 30 September 2018. Adult patients (>=18 years) who received both an intravenous BAA and CCB (in either order) within 6 hours were included. Primary outcomes were the incidence of bradycardia (heart rate <60 bpm) or hypotension (systolic blood pressure <90mmHg) after administration of the second medication. Secondary outcomes were associated diastolic blood pressure changes and administratively assigned primary and secondary diagnoses.
Result(s): Overall 56 ED patients met inclusion criteria. The median time between medication administration was 110 minutes for the cohort. The median decrease in pulse was 42 bpm. The median decrease in systolic blood pressure was 26mmHg, and the median diastolic blood pressure decrease was 11mmHg. According to the prespecified endpoints, 8.9% developed bradycardia, 8.9% developed systolic hypotension, and 17.9% developed either complication. These complications occurred at median times after second medication administration of 36 minutes for bradycardia and 10 minutes for hypotension. The most common diagnosis in patients who received concomitant BAA and CCB administration was atrial fibrillation (n= 39). All patients who developed bradycardia had atrial fibrillation (n= 4) or atrial flutter (n= 1). All patients who developed hypotension had atrial fibrillation (n= 5).
Conclusion(s): Despite a lack of published data, the administration of both BAAs and CCBs within 6 hours can cause significant hypotension and bradycardia in emergency department patients. Avoidance of concurrent administration of these medication classes or assurance of antidotal availability or pretreatment (i.e. with calcium salts) should be strongly encouraged