Systemic and anti-nociceptive effects of prolonged lidocaine, ketamine, and butorphanol infusions alone and in combination in healthy horses.
Authors: Elfenbein Johanna R, Robertson Sheilah A, MacKay Robert J, KuKanich Butch, Sanchez L
Journal: BMC veterinary research
Summary
# Editorial Summary: Systemic Effects of Prolonged Analgesic Infusions in Horses Prolonged constant rate infusions (CRI) of lidocaine, ketamine, and butorphanol are increasingly used in equine practice to manage severe pain, yet their effects on gastrointestinal function—a critical concern given the species' predisposition to colic—remain incompletely characterised. Elfenbein and colleagues administered these agents individually and in combination to healthy horses over an extended period, monitoring gastrointestinal transit time, behavioural responses, and thermal nociceptive thresholds to evaluate both analgesic efficacy and systemic safety. The combination protocols demonstrated superior pain-relieving effects compared with single agents, with the three-drug combination showing the most pronounced anti-nociceptive activity; however, all prolonged infusions produced measurable delays in gastrointestinal transit, raising important questions about the risk-benefit profile in colicky or critically ill patients. These findings suggest that whilst multimodal CRI protocols offer enhanced analgesia for severe pain management, clinicians must weigh analgesic gains against potential gastrointestinal complications, necessitating careful patient selection and concurrent prokinetic support. For equine practitioners, this work underscores the importance of individualised pain protocols and continued vigilance for signs of ileus or reduced gut motility when administering prolonged infusions, particularly in animals already compromised by primary gastrointestinal or systemic disease.
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Practical Takeaways
- •When using prolonged infusions of these drugs for severe pain, monitor gastrointestinal function closely as altered transit is a predictable side effect
- •Understand that lidocaine, ketamine, and butorphanol CRIs are effective for pain relief but require careful patient selection and monitoring in clinical cases
- •Consider the trade-offs between pain control efficacy and gastrointestinal complications when choosing between single agents and combinations
Key Findings
- •Prolonged CRI of lidocaine, ketamine, and butorphanol produce anti-nociceptive effects with measurable changes in thermal nociceptive threshold in healthy horses
- •These drug infusions are associated with altered gastrointestinal transit, a significant side effect concern for clinical pain management
- •Combination infusions and single-agent infusions demonstrated different systemic and behavioral effects requiring careful clinical consideration