title: The use of force plate measurements to titrate the dosage of a new COX-2 inhibitor in lame horses.
abstract: BACKGROUND
  Lameness is a highly prevalent condition in horses and the principal cause of removal from athletic activity. In clinical studies to evaluate nonsteroidal anti-inflammatory drug therapies, force plates are commonly used to assess improvement of lameness objectively.
  
  
  OBJECTIVE
  To use a force plate to determine the optimal dose of a new COX-2 inhibitor (firocoxib) that will reduce lameness, when administered orally to horses once daily.
  
  
  METHODS
  Sixty-four horses that exhibited chronic lameness presumed due to osteoarthritis, including navicular disease, in at least one of the frontlimbs and at a stable level of severity, were included. Horses were treated per os s.i.d. for 7 days as follows: vehicle control, firocoxib at 0.05, 0.1 or 0.25 mg/kg bwt. Force plate analysis of each horse was done for the selected (most) lame frontlimb at trot. Once between Days -19 and -4 (initial examination), and again on Day -2 or -1 (baseline), pretreatment force plate assessments were performed, and thereafter horses were assessed on Days 0, 2 and 6, approximately 10 h post treatment each time. Peak vertical force (PVF) and lameness grades at initial examination and at baseline, and their change from baseline in the 4 different treatment groups were analysed statistically at a significance level of P < 0.05.
  
  
  RESULTS
  The PVF results were found to be superior to vehicle control already at Day 0 for 0.25 mg/kg bwt and at Days 2 and 6 for 0.1 and 0.25 mg/kg bwt (P < 0.05). Mean clinical lameness for both concentrations decreased > 1 grade at Day 6.
  
  
  CONCLUSIONS
  With the dosage of 0.25 mg/kg bwt lameness did not improve more than with 0.1 mg/kg bwt. Thus, 0.1 mg/kg bwt s.i.d. was considered to be the effective dose at reducing chronic lameness in horses presumed due to osteoarthritis, including navicular disease.
authors.affiliation: Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 114, 3584 CM Utrecht, The Netherlands.
authors.forename: W
authors.initials: W
authors.lastname: Back
authors.forename: C G
authors.initials: CG
authors.lastname: MacAllister
authors.forename: M C V
authors.initials: MC
authors.lastname: van Heel
authors.forename: M
authors.initials: M
authors.lastname: Pollmeier
authors.forename: P D
authors.initials: PD
authors.lastname: Hanson
mesh_terms: D015107:4-Butyrolactone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000627:therapeutic use*; D001696:Biomechanical Phenomena; D052246:Cyclooxygenase 2 Inhibitors / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D005260:Female; D005552:Forelimb; D006734:Horse Diseases / Q000188:drug therapy*; D006736:Horses; D007794:Lameness, Animal / Q000188:drug therapy*; D008297:Male; D011312:Pressure; D013450:Sulfones / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D052246:Cyclooxygenase 2 Inhibitors; D013450:Sulfones; D015107:4-Butyrolactone; C487384:firocoxib