Evaluation of topically administered diclofenac liposomal cream for treatment of horses with experimentally induced osteoarthritis

Authors: 
David D. Frisbie, DVM, PhD; C. Wayne McIlwraith, BVSc, PhD; Chris E. Kawcak, DVM, PhD; Natasha M. Werpy, DVM; Gregory L. Pearce, MStat
Volume: 
70
Number: 
2
Pages: 
210-215
Journal: 
American Journal of Veterinary Research
Date: 
February 2009

Abstract
American Journal of Veterinary Research
February 2009, Vol. 70, No. 2, Pages 210-215
doi: 10.2460/ajvr.70.2.210

Evaluation of topically administered diclofenac liposomal cream for treatment of horses with experimentally induced osteoarthritis

David D. Frisbie, DVM, PhD; C. Wayne McIlwraith, BVSc, PhD; Chris E. Kawcak, DVM, PhD; Natasha M. Werpy, DVM; Gregory L. Pearce, MStat
Gail Holmes Equine Orthopaedic Research Center, Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523. (Frisbie, McIlwraith, Kawcak, Werpy); Innovative Data Resources, 11 Badger Rd, Asheville, NC 28803. (Pearce)
Supported by IDEXX Pharmaceuticals, Greensboro, NC.

The authors thank Dr. Randy C. Lynn and Dr. Robert O. Keene for technical support.

Address correspondence to Dr. Frisbie.
Objective—To assess the clinical, biochemical, and histologic effects of topically administered diclofenac liposomal cream (DLC) in the treatment of horses with experimentally induced osteoarthritis.

Animals—24 horses.

Procedures—Osteoarthritis was induced arthroscopically in 1 middle carpal joint of all horses. Eight horses treated with DLC were given 7.3 g twice daily via topical application. Eight horses treated with phenylbutazone were given 2 g orally once daily. Eight control horses received no treatment. Evaluations included clinical, radiographic, magnetic reso-nance imaging, synovial fluid, gross, and histologic examinations as well as histochemical and biochemical analyses.

Results—No adverse treatment-related events were detected. Horses that were treated with DLC or phenylbutazone had significant clinical improvement of lameness, unlike the control horses. Treatment with DLC induced significant improvement in staining and total articular glycosaminoglycan content, compared with no treatment. Treatment with phen-ylbutazone induced significant reduction in synovial fluid prostaglandin E2 concentration, compared with DLC and no treatment. Treatment with DLC induced significantly less radial carpal bone sclerosis and overall gross cartilage erosion, compared with phenylbutazone.

Conclusions and Clinical Relevance—Results indicated that DLC had both clinical sign–modifying and disease-modifying effects. Only clinical sign–modifying effects were detected in association with phenylbutazone administration. Treatment with DLC had significant beneficial effects, compared with phenylbutazone, and no detrimental effects. Results suggested that DLC is a viable therapeutic option for horses with osteoarthritis.