title: Efficacy of cyclo-oxygenase inhibition by two commercially available firocoxib products in horses.
abstract: BACKGROUND
  Two firocoxib preparations for oral use are approved for use in animals in many countries: a chewable canine tablet and an equine paste. In order to reduce costs, many veterinarians use the canine product in horses even though this is an off-label use of the preparation.
  
  
  OBJECTIVE
  To determine the relative efficacy of 2 commercially available firocoxib products to inhibit prostaglandin E₂ (PGE2) synthesis after oral dosing in horses.
  
  
  METHODS
  A crossover design using 8 adult horses (n = 4 for each preparation during each treatment period). Body weight range 532-614 kg.
  
  
  METHODS
  Horses received 57 mg of the assigned firocoxib preparation orally once daily for 7 days, with a 14 day washout period between drug crossover. Ten healthy adult light breed horses were used as no-treatment controls. During each treatment period, blood was taken before dosing on Days 0 and 7 and on Day 7 1 h after dosing for ex vivo lipopolysaccharide (LPS) stimulation to induce (PGE₂ ) synthesis. Heparinised plasma was also collected on Day 7 immediately prior to and 1 h after dosing to determine plasma firocoxib concentrations.
  
  
  RESULTS
  In the control group, there was no significant change in LPS-induced PGE2 over time. In contrast, immediately prior to and 1 h after treatment on Day 7, the mean LPS-induced PGE₂ concentration decreased significantly compared to Day 0 values in all treated horses. There was no difference in PGE₂ or plasma firocoxib concentrations between firocoxib treatment groups.
  
  
  CONCLUSIONS
  In this model, the canine chewable preparation of firocoxib was as effective as the equine paste formulation at reducing LPS-induced PGE₂ synthesis.
  
  
  CONCLUSIONS
  The canine chewable preparation of firocoxib may be a suitable alternative to the paste formulation in horses for situations where extra-label drug use can be legally justified. The Summary is available in Chinese - see Supporting information.
authors.affiliation: Department of Large Animal Medicine, University of Georgia, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Barton
authors.forename: E
authors.initials: E
authors.lastname: Paske
authors.forename: N
authors.initials: N
authors.lastname: Norton
authors.forename: D
authors.initials: D
authors.lastname: King
authors.forename: S
authors.initials: S
authors.lastname: Giguère
authors.forename: S
authors.initials: S
authors.lastname: Budsberg
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000494:pharmacology; D000284:Administration, Oral; D000818:Animals; D018592:Cross-Over Studies; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology*; D015232:Dinoprostone / Q000037:antagonists & inhibitors* / Q000378:metabolism; D004304:Dosage Forms; D006736:Horses; D013450:Sulfones / Q000494:pharmacology*
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D004304:Dosage Forms; D013450:Sulfones; D015232:Dinoprostone; D015107:4-Butyrolactone; C487384:firocoxib
keywords: COX1 sparing; Equioxx; Previcox; horse; nonsteroidal anti-inflammatory drugs; prostaglandin E2