Effects of Intravenous Flunixin Meglumine, Phenylbutazone, and Acupuncture on Ocular Pain Scores in the Horse: A Pilot Study.
Authors: Makra Zita, Csereklye Nóra, Riera Marian Matas, McMullen Richard J, Veres-Nyéki Kata
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Ocular Pain Management in Horses Corneal injuries in horses present a significant clinical challenge, particularly regarding effective pain relief assessment and management. Researchers in this 2021 pilot study compared intravenous flunixin meglumine, phenylbutazone, and electroacupuncture against a control group, using standardised corneal debridement procedures in four horses with repeated pain scoring across 18 timepoints and 11 parameters to establish which modalities best reduced ocular pain. Flunixin meglumine demonstrated superior efficacy, achieving pain scores 27% lower than the control group during the critical first 46 hours post-injury, whilst electroacupuncture and phenylbutazone showed more modest improvements (14% and 12% reduction respectively). Importantly, the researchers identified that only five ocular parameters (blepharospasm, ocular discharge, eyelid swelling, third eyelid protrusion, and conjunctival redness) reliably indicated pain severity, whereas systemic markers like heart rate and corneal touch threshold proved clinically irrelevant. Practitioners managing corneal injuries should prioritise flunixin meglumine for acute pain control and focus clinical assessment on observable ocular signs rather than more laborious multifactorial scoring systems, though the small sample size warrants confirmation in larger cohorts before definitive treatment protocols are established.
Read the full abstract on PubMed
Practical Takeaways
- •When managing corneal injuries in horses, intravenous flunixin meglumine provides superior pain relief compared to phenylbutazone or acupuncture alone
- •Focus on ocular signs (squinting, tearing, chemosis, blepharospasm, conjunctival injection) to accurately assess pain severity in horses with eye injuries rather than relying on heart rate or behavioral responses
- •This pilot study is limited by small sample size (4 horses); larger trials are needed before broadly recommending these findings for routine clinical practice
Key Findings
- •Flunixin meglumine produced the lowest pain scores (1114) compared to electroacupuncture (1356), phenylbutazone (1397), and control (1580)
- •Flunixin meglumine showed significantly lower pain scores (P = 0.01) versus control during the first 46 hours post-corneal wounding
- •Five ocular signs (eye squinting, tearing, chemosis, blepharospasm, conjunctival injection) were reliable pain indicators; heart rate and behavioral parameters were not useful for assessing ocular pain
- •Corneal pain was significantly reduced by day three post-operatively (P = 0.03) across all treatment groups