Veterinarians often give penicillin to horses during surgery to prevent infection, but the speed of injection may influence how the horse’s cardiovascular system reacts. In a study of 29 horses under general anesthesia, researchers compared two methods of giving penicillin: a fast injection over one minute and a slower one over ten minutes.
Severely injured foal receiving first aid.
In equine anesthesia, every decision—from drug choice to administration technique—should prioritize minimizing patient risk.
© 2016 by Keith Bowers New window.
Both methods caused a drop in blood pressure, but the fast injection led to a more dramatic decrease. The slower, more diluted injection resulted in a gentler decline, suggesting it may be safer during surgery.
Sudden drops in blood pressure during surgery can be risky. This study suggests that slowing down the penicillin injection and diluting it more could help keep horses safer under anesthesia. These findings highlight the importance of not just what medication is given, but how it’s administered.
Another Ontario Veterinary College (OVC) study comparing two lidocaine infusion protocols to further explore how intraoperative management affects cardiovascular stability and recovery quality is also soon to be published.
“In equine anesthesia, every decision—from drug choice to administration technique—should prioritize minimizing patient risk. Our goal is always to support the horse in all phases of anesthesia (from induction to full recovery) to achieve optimal outcomes,” said Dr. Alexander Valverde, Professor, DVM, DVSc., Diplomate ACVAA at OVC.
Valverde A, Sinclair M, Morey T, Cruz AM. Effect of rapid and slow intravenous injection of sodium penicillin on arterial blood pressure in isoflurane-anesthetized horses during surgery. Can Vet J. 2024 May;65(5):453–458. PMID: 39863515
https://pubmed.ncbi.nlm.nih.gov/39863515
Press release by Equine Guelph Research, Research