title: Pharmacokinetics of hydromorphone hydrochloride in healthy dogs.
abstract: OBJECTIVE
  To assess the pharmacokinetics of hydromorphone administered intravenously (IV) or subcutaneously (SC) to dogs.
  
  
  METHODS
  Randomized experimental trial.
  
  
  METHODS
  Seven healthy male neutered Beagles aged 12.13 +/- 1.2 months and weighing 11.72 +/- 1.10 kg.
  
  
  METHODS
  The study was a randomized Latin square block design. Dogs were randomly assigned to receive hydromorphone hydrochloride 0.1 mg kg(-1) or 0.5 mg kg(-1) IV (n = 4 dogs) or 0.1 mg kg(-1) (n = 6) or 0.5 mg kg(-1) (n = 5) SC on separate occasions with a minimum 14-day washout between experiments. Blood was sampled via a vascular access port at serial intervals after drug administration. Serum was analyzed by mass spectrometry. Pharmacokinetic parameters were determined with computer software.
  
  
  RESULTS
  Serum concentrations of hydromorphone decreased quickly after both routes of administration of either dose. The serum half-life, clearance, and volume of distribution after IV hydromorphone at 0.1 mg kg(-1) were 0.57 hours (geometric mean), 106.28 mL minute(-1) kg(-1), and 5.35 L kg(-1), and at 0.5 mg kg(-1) were 1.00 hour, 60.30 mL minute(-1) kg(-1), and 5.23 L kg(-1), respectively. The serum half-life after SC hydromorphone at 0.1 mg kg(-1) and 0.5 mg kg(-1) was 0.66 hours and 1.11 hours, respectively.
  
  
  CONCLUSIONS
  Hydromorphone has a short half-life, suggesting that frequent dosing intervals are needed. Based on pharmacokinetic parameters calculated in this study, 0.1 mg kg(-1) IV or SC q 2 hours or a constant rate infusion of hydromorphone at 0.03 mg kg(-1) hour(-1) are suggested for future studies to assess the analgesic effect of hydromorphone.
authors.affiliation: PharmCATS and the Department of Anatomy and Physiology, Kansas State University, Manhattan, KS, USA.
authors.forename: Butch
authors.initials: B
authors.lastname: KuKanich
authors.forename: Brynn K
authors.initials: BK
authors.lastname: Hogan
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Krugner-Higby
authors.forename: Lesley J
authors.initials: LJ
authors.lastname: Smith
mesh_terms: D000701:Analgesics, Opioid / Q000097:blood / Q000493:pharmacokinetics*; D000818:Animals; D019540:Area Under Curve; D004285:Dogs; D006207:Half-Life; D004091:Hydromorphone / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male
chemical_list: D000701:Analgesics, Opioid; D004091:Hydromorphone