title: Endogenous Glucocorticoid Response to Single-Dose Dexamethasone for Croup in Children: A Pharmacodynamic Study.
abstract: OBJECTIVE
  Dexamethasone is associated with adrenal insufficiency in adults and children with chronic disease. This association has not been studied after single-dose oral dexamethasone, the standard of care for children with croup. We hypothesized that single-dose oral dexamethasone in children with croup is associated with a transient decrease in endogenous glucocorticoids.
  
  
  METHODS
  We conducted a prospective, 2-arm, pharmacodynamic study of single-dose oral dexamethasone 0.6 mg/kg (maximum, 12 mg) in children older than 2 years with croup compared with controls (children with febrile upper respiratory tract infections who did not receive dexamethasone). Primary outcome was urinary 6β-hydroxycortisol-cortisol ratio.
  
  
  RESULTS
  Twenty-seven children were analyzed (22 with croup and 5 with upper respiratory tract infections). Median 6β-hydroxycortisol-cortisol ratios before dexamethasone, the following morning, and on days 1, 3, and 7 were 2.8, 2.2, 2.0, 2.8, and 2.6, respectively. Among controls, the median 6β-hydroxycortisol-cortisol ratios at the same time intervals was 1.9, 1.5, 1.8, 2.5, and 1.7, respectively. There were no significant differences in the change from time 0 between groups at any time point. There were no serious adverse events or infectious complications.
  
  
  CONCLUSIONS
  Single-dose oral dexamethasone is not associated with decreased endogenous corticosteroid levels in children with croup. Future studies should use criterion standard tests to rule out suppression of the hypothalamic-pituitary-adrenal axis and be powered sufficiently to identify adverse clinical outcomes.
authors.affiliation: From the Children's Hospital, London Health Sciences Centre.|Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario.
authors.forename: Natasha
authors.initials: N
authors.lastname: Gill
authors.affiliation: From the Children's Hospital, London Health Sciences Centre.|Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario.
authors.forename: Natalie
authors.initials: N
authors.lastname: Sirizzotti
authors.affiliation: Alberta Children's Hospital, University of Calgary, Calgary, Alberta.
authors.forename: David
authors.initials: D
authors.lastname: Johnson
authors.affiliation: From the Children's Hospital, London Health Sciences Centre.|Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario.
authors.forename: Gary
authors.initials: G
authors.lastname: Joubert
authors.affiliation: Robarts Research Institute.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Kucey
authors.affiliation: Robarts Research Institute.
authors.forename: Alvin
authors.initials: A
authors.lastname: Tieu
authors.affiliation: Robarts Research Institute.
authors.forename: Brad L
authors.initials: BL
authors.lastname: Urquhart
authors.affiliation: Division of Emergency Medicine, Western University.
authors.forename: Melanie
authors.initials: M
authors.lastname: Columbus
authors.affiliation: From the Children's Hospital, London Health Sciences Centre.|Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario.|Division of Emergency Medicine, Western University.
authors.forename: Rodrick
authors.initials: R
authors.lastname: Lim
authors.affiliation: From the Children's Hospital, London Health Sciences Centre.|Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario.|Robarts Research Institute.|Division of Emergency Medicine, Western University.
authors.forename: Michael
authors.initials: M
authors.lastname: Rieder
authors.affiliation: From the Children's Hospital, London Health Sciences Centre.|Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario.|Division of Emergency Medicine, Western University.
authors.forename: Shruti
authors.initials: S
authors.lastname: Mehrotra
authors.affiliation: Robarts Research Institute.
authors.forename: Emily D
authors.initials: ED
authors.lastname: Hartjes
authors.affiliation: From the Children's Hospital, London Health Sciences Centre.|Department of Paediatrics, Schulich School of Medicine and Dentistry, Western University, London, Ontario.|Division of Emergency Medicine, Western University.|Children's Health Research Institute, London Health Sciences Centre, London, Ontario, Canada.
authors.forename: Naveen
authors.initials: N
authors.lastname: Poonai
mesh_terms: D000284:Administration, Oral; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage* / Q000494:pharmacology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003440:Croup / Q000188:drug therapy*; D003907:Dexamethasone / Q000008:administration & dosage* / Q000494:pharmacology; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000494:pharmacology; D006801:Humans; D006854:Hydrocortisone / Q000031:analogs & derivatives* / Q000652:urine*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects; D008297:Male; D010913:Pituitary-Adrenal System / Q000187:drug effects; D011446:Prospective Studies
chemical_list: D000893:Anti-Inflammatory Agents; D005938:Glucocorticoids; C001380:6 beta-hydroxycortisol; D003907:Dexamethasone; D006854:Hydrocortisone