Flunixin Meglumine, Phenylbutazone, and Acupuncture on Ocular Pain Scores

Effects of Intravenous Flunixin Meglumine, Phenylbutazone, and Acupuncture on Ocular Pain Scores in the Horse: A Pilot Study
J Equine Vet Sci. 2021 Mar;98:103375.
Authors
Zita Makra 1 , Nóra Csereklye 2 , Marian Matas Riera 3 , Richard J McMullen Jr 4 , Kata Veres-Nyéki 5
Affiliations

1 Equine Department and Clinic, University of Veterinary Medicine Budapest, Hungary. Electronic address: makra.zita@univet.hu.
2 Equine Department and Clinic, University of Veterinary Medicine Budapest, Hungary.
3 Memvet Oftalmologia, Palma, Mallorca, Spain.
4 Auburn University, JT Vaughan Large Animal Teaching Hospital, Auburn, AL.
5 Royal Veterinary College, Anaesthesia and Analgesia Service, London, UK.

PMID: 33663725
DOI: 10.1016/j.jevs.2021.103375

Abstract

In this controlled, blinded, randomized block pilot study, the main objective was to evaluate the effectiveness of intravenous flunixin meglumine, phenylbutazone, and acupuncture on ocular pain relief using a multifactorial pain scale in the horse. Four experimental horses underwent corneal epithelial debridement in four sessions, when a randomly selected treatment or a control was used. All horses were pain scored before corneal wounding, then at 18 time points, when 11 parameters were allocated. Differences in the area under the curve of pain scores between the treatment groups were analyzed using a paired t-test. Corneal pain was significantly reduced by the third postoperative day (P = .03) when all 11 parameters were considered. Five ocular signs showed significant differences between treatments and proved to be good indicators of ocular pain. The other parameters (heart rate, corneal touch threshold, respond to palpation, and three behavioral parameters) were determined to be irrelevant when evaluating the degree of pain. When considering the five ocular signs, the lowest pain score was attributed to the flunixin meglumine group (1114), followed by the electroacupuncture group (1356), the phenylbutazone group (1397), and the control group (1580). There were significantly lower pain scores (P = .01) in the flunixin meglumine group when compared with those recorded in the control group during the first 46 hours. Flunixin meglumine was the most effective treatment at reducing ocular pain in the horse. In the future, a reduction in the number of pain score parameters and more precisely defined image evaluation criteria could be used.