Contemporary use of acepromazine in the anaesthetic management of male horses and ponies: a retrospective study and opinion poll.

The research explores the use of acepromazine, a tranquilizer for horses, in its anesthetic management for male horses and ponies and the associated risks. A low risk of permanent penile dysfunction was found, suggesting no need for restricted use in intact males versus geldings and mares.

Research Methodology

• The medical records of male horses and ponies that were anaesthetised and treated perianaesthetically with acepromazine were analysed.
• The study gathered demographic data, information on the time and dose of acepromazine administration, types of drugs co-administered, and quality of induction and recovery from anaesthesia.
• The research also examined arterial blood pressures and the occurrence of penile dysfunction.
• The study also included a poll of practicing ACVA and ECVAA diplomates on the use of acepromazine and its effects on blood pressure and penile dysfunction in horses.

Findings

• Out of all the males, 11% received perianaesthetic acepromazine. This was most often used for premedication.
• Anaesthetic induction was successful in almost all animals and recovery was rated good or very good in 70% of animals, with 74% standing after one or two attempts.
• For 14 horses, 2.4% experienced penile prolapse lasting between 0.5 to 4 hours, and for one stallion, this lasted over 12 hours but less than 18 hours.
• The survey found that most anaesthesiologists use acepromazine primarily for premedication with other sedatives and analgesics. This is more frequent in geldings and mares.
• Instances of persistent intraoperative hypotension were not often reported, and penile prolapse following acepromazine administration, lasting for more than 12 hours, was recalled by only 5% of the surveyed anaesthesiologists, with only one recalling three cases of irreversible penile prolapse in 20 years of anaesthesia practice.

Conclusion

• The study indicates that the extremely low risk of permanent penile dysfunction does not justify the need for a more restricted use of acepromazine for intact males as opposed to geldings and mares.