title: Emergency department visits for antibiotic-associated adverse events.
abstract: BACKGROUND
  Drug-related adverse events are an under-appreciated consequence of antibiotic use, and the national magnitude and scope of these events have not been studied. Our objective was to estimate and compare the numbers and rates of emergency department (ED) visits for drug-related adverse events associated with systemic antibiotics in the United States by drug class, individual drug, and event type.
  
  
  METHODS
  We analyzed drug-related adverse events from the National Electronic Injury Surveillance System-Cooperative Adverse Drug Event Surveillance project (2004-2006) and outpatient prescriptions from national sample surveys of ambulatory care practices, the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey (2004-2005).
  
  
  RESULTS
  On the basis of 6614 cases, an estimated 142,505 visits (95% confidence interval [CI], 116,506-168,504 visits) annually were made to US EDs for drug-related adverse events attributable to systemic antibiotics. Antibiotics were implicated in 19.3% of all ED visits for drug-related adverse events. Most ED visits for antibiotic-associated adverse events were for allergic reactions (78.7% of visits; 95% CI, 75.3%-82.1% of visits). One-half of the estimated ED visits were attributable to penicillins (36.9% of visits; 95% CI, 34.7%-39.2% of visits) and cephalosporins (12.2%; 95% CI, 10.9%-13.5%). Among commonly prescribed antibiotics, sulfonamides and clindamycin were associated with the highest rate of ED visits (18.9 ED visits per 10,000 outpatient prescription visits [95% CI, 13.1-24.7 ED visits per 10,000 outpatient prescription visits] and 18.5 ED visits per 10,000 outpatient prescription visits [95% CI, 12.1-25.0 ED visits per 10,000 outpatient prescription visits], respectively). Compared with all other antibiotic classes, sulfonamides were associated with a significantly higher rate of moderate-to-severe allergic reactions (4.3% [95% CI, 2.9%-5.8%] vs. 1.9 % [95% CI, 1.5%-2.3%]), and sulfonamides and fluoroquinolones were associated with a significantly higher rate of neurologic or psychiatric disturbances (1.4% [95% CI, 1.0%-1.7%] vs. 0.5% [95% CI, 0.4%-0.6%]).
  
  
  CONCLUSIONS
  Antibiotic-associated adverse events lead to many ED visits, and allergic reactions are the most common events. Minimizing unnecessary antibiotic use by even a small percentage could significantly reduce the immediate and direct risks of drug-related adverse events in individual patients.
authors.affiliation: Division of Healthcare Quality Promotion, National Center for Detection, Preparedness, and Control of Infectious Diseases, Coordinating Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. nshehab@cdc.gov
authors.forename: Nadine
authors.initials: N
authors.lastname: Shehab
authors.forename: Priti R
authors.initials: PR
authors.lastname: Patel
authors.forename: Arjun
authors.initials: A
authors.lastname: Srinivasan
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Budnitz
mesh_terms: D016907:Adverse Drug Reaction Reporting Systems; D000900:Anti-Bacterial Agents / Q000009:adverse effects*; D002511:Cephalosporins / Q000009:adverse effects; D004342:Drug Hypersensitivity / Q000453:epidemiology; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D006801:Humans; D010406:Penicillins / Q000009:adverse effects; D014481:United States / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D010406:Penicillins