title: The prevalence and impact of antimicrobial allergies and adverse drug reactions at an Australian tertiary centre.
abstract: BACKGROUND
  The prevalence and impact of antimicrobial "allergy" labels and Adverse Drug Reactions (ADRs) on antibiotic usage and antimicrobial stewardship initiatives is ill defined. We sought to examine the rate of antimicrobial "allergy labels" at our tertiary referral centre and impacts on antimicrobial usage and appropriateness.
  
  
  METHODS
  Two inpatient antimicrobial prevalence surveys were conducted over a 1-week period in November 2013 and 2014 as part of the prospective National Antimicrobial Prescribing Survey (NAPS). Post survey, patients recorded in the NAPS database were assigned to two groups based upon recorded antimicrobial "allergy label" and ADR: (i) Antimicrobial Allergy/ADR (AA) or (ii) No Antimicrobial Allergy/ADR (NAA). Antimicrobial usage and antimicrobial appropriateness were compared between AA and NAA groups.
  
  
  RESULTS
  From 509 identified patients the prevalence of an antimicrobial allergy or ADR was 25 %. The prevalence of "allergy labels"/ADR was 10 % (51/509) for penicillin V/G, 5 % (24/509) cephalosporins, 4 % (22/509) trimethroprim-sulfamethoxazole and 3 % (17/509) aminopenicillins. One thousand and seventy antimicrobials were prescribed during the study periods, the median antimicrobial duration was longer in the AA versus NAA group (6 days vs. 4 days; p = 0.018), and proportion of inappropriate antimicrobial prescribing higher in the AA group compared with NAA (29 %; 35/120 vs. 23 %; 86/367, p = 0.22). Oral antimicrobial administration was higher in the NAA than AA group (60 %; 177/297 vs. 46 %; 356/793, p = 0.0001). The proportion of patients that received a β-lactam was lower in the AA versus NAA group (60 % vs. 79 %, p = 0.0001).
  
  
  CONCLUSIONS
  In an Australian tertiary referral centre an antimicrobial "allergy" or ADR label was found to significantly impacted on rate of oral antimicrobial administration, beta-lactam usage, antimicrobial duration and antimicrobial appropriateness.
authors.affiliation: Department of Infectious Diseases, Alfred Health and Monash University, Melbourne, VIC, Australia. j.trubiano@alfred.org.au.|Department of Infectious Diseases, Austin Health, Melbourne, VIC, Australia. j.trubiano@alfred.org.au.|Department of Medicine, University of Melbourne, Melbourne, VIC, Australia. j.trubiano@alfred.org.au.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Trubiano
authors.affiliation: Department of Pharmacy, Alfred Health, Melbourne, VIC, Australia. k.cairns@alfred.org.au.
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Cairns
authors.affiliation: Monash University, Melbourne, VIC, Australia. jaeva8@student.monash.edu.
authors.forename: Jacqui A
authors.initials: JA
authors.lastname: Evans
authors.affiliation: Monash University, Melbourne, VIC, Australia. adin8@student.monash.edu.
authors.forename: Amally
authors.initials: A
authors.lastname: Ding
authors.affiliation: Department of Pharmacy, Alfred Health, Melbourne, VIC, Australia. tuan.nguyen@alfred.org.au.
authors.forename: Tuan
authors.initials: T
authors.lastname: Nguyen
authors.affiliation: Pharmacy Department, Alfred Hospital and Centre for Medication Use and Safety, Monash University, Melbourne, VIC, Australia. Michael.dooley@alfred.org.au.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Dooley
authors.affiliation: Department of Infectious Diseases, Alfred Health and Monash University, Melbourne, VIC, Australia. allen.cheng@med.monash.edu.au.|Infection Prevention and Healthcare Epidemiology Unit, Alfred Health and Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia. allen.cheng@med.monash.edu.au.
authors.forename: Allen C
authors.initials: AC
authors.lastname: Cheng
mesh_terms: D000284:Administration, Oral; D000890:Anti-Infective Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001315:Australia / Q000453:epidemiology; D002511:Cephalosporins / Q000009:adverse effects; D004342:Drug Hypersensitivity / Q000453:epidemiology*; D004348:Drug Labeling; D005260:Female; D006306:Health Surveys; D006801:Humans; D057970:Inappropriate Prescribing; D007297:Inpatients; D008297:Male; D008875:Middle Aged; D010406:Penicillins / Q000009:adverse effects; D062606:Tertiary Care Centers; D047090:beta-Lactams / Q000009:adverse effects
chemical_list: D000890:Anti-Infective Agents; D002511:Cephalosporins; D010406:Penicillins; D047090:beta-Lactams