[Anesthesia by injection of xylazine, ketamine and the benzodiazepine derivative climazolam and the use of the benzodiazepine antagonist Ro 15-3505].

The research study investigates the use of a combination of injectable anaesthetics – xylazine, ketamine, and climazolam- and a benzodiazepine antagonist, Ro 15-3505, for minor surgery in horses. The findings suggest that the blend effectively induce anesthesia, control its duration, and facilitate a smoother recovery period.

Research Method and Subjects

• The researchers carried out their study on 25 horses that were brought into the clinic for minor surgical operations.
• The horses were first sedated using xylazine at a dosage of 1.1 milligrams per kilogram intravenously (i.v.).
• Then they introduced anesthesia using ketamine at a dosage of 2.2 milligrams per kilogram intravenously.
• Once the horses were in lateral recumbency (lying on their sides), they administered climazolam, a derivative of benzodiazepine, at doses of either 0.1 mg/kg (for 10 of the horses) or 0.2 mg/kg (for the remaining 15).

Anesthesia Maintenance and Termination

• To maintain the state of anesthesia, they periodically injected the horses with additional ketamine at 1.1 mg/kg every 9-12 minutes.
• Following the completion of the surgical procedures, about 20 minutes after the last ketamine dose, they administered Ro 15-3505, a benzodiazepine antagonist, at a dose of 0.01 mg/kg or 0.02 mg/kg intravenously.

Results and Implications

• The results indicated that climazolam was effective in suppressing the adverse reactions typically associated with ketamine usage, such as insufficient muscle relaxation, hyperacusis (heightened hearing sensitivity), and seizures.
• The administration of benzodiazepine antagonist, Ro 15-3505, gave the researchers the ability to dictate the duration of the anesthesia in a reliable manner.
• In most instances, the combination led to a gradual and predictable recovery phase following surgery.
• The study thus provides veterinary clinicians with an effective cocktail of drugs for inducing, maintaining and controlling anesthesia in horses undergoing minor surgery.