Treatment of poisoning caused by β-adrenergic and calcium-channel blockers

GREENE SHEPHERD, PHARM.D., DABAT, is Clinical Associate Professor, Medical College of Georgia, 1120 15th Street, CJ-1020, Augusta, GA 30912-2450 ([email protected]). Copyright © 2006, American Society of Health-System Pharmacists, Inc. All rights reserved. 1079-2082/06/1001-1828$06.00. DOI 10.2146/ajhp060041 Overdoses with cardiovascular drugs are associated with significant morbidity and mortality. Beta-adrenergic blockers and calcium-channel blockers (CCBs) represent two of the most important classes of cardiovascular drugs. This article will review the toxicity and treatment of β-blocker and CCB overdoses. Overdoses with cardiovascular drugs typically result from exploratory ingestions by children or intentional ingestions by suicidal adults. Other reasons for intoxications include medication errors (e.g., double dosing) or adverse effects. Interactions with drugs that affect cardiac conduction, inotropy, or metabolism via the cytochrome P450 enzymes may also produce toxicity. According to the 2004 Toxic Exposure Surveillance System (TESS) report, 3% (n = 74,145) of the total exposures reported in TESS documented by the American Association of Poison Control Centers were due to cardiovascular medications. Poisonings with these drugs resulted in 162 deaths, making cardiovascular drugs the fifth leading cause of death in the TESS database. CCBs and β-blockers accounted for 37% of these exposures and the majority of cases resulting in life-threatening effects or death. The CCB and β-blocker drugs most frequently implicated in fatalities are verapamil and propranolol, respectively. Newer agents in both classes have better safety profiles.