The use of force plate measurements to titrate the dosage of a new COX-2 inhibitor in lame horses.
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.
Back
W
W
Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 114, 3584 CM Utrecht, The Netherlands.
MacAllister
C G
CG
van Heel
M C V
MC
Pollmeier
M
M
Hanson
P D
PD
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*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D052246:Cyclooxygenase 2 Inhibitors; D013450:Sulfones; D015107:4-Butyrolactone; C487384:firocoxib