Hot Literature: Investigating a detomidine sublingual gel for equine sedation

Research on using sublingual detomidine in horses to produce mild sedation is getting some serious attention. Included in the 2010 American Association of Equine Practitioner's annual convention, followed by journal publication, an efficacy study suggests that there may be an alternative to injectable sedatives in horses. Indeed, the prospect of an easy-to-administer medication to allow for minor procedures in horses requiring sedation is appealing and could allow laypeople, as well as veterinarians, a way to safely and successfully perform minor procedures in horses that require mild sedation and are either needle-shy or have caregivers uncomfortable with administering injections.

This study was conducted at private equine veterinary practices in seven states. Healthy horses that had a history of requiring sedation for various minor procedures were randomly selected to either receive a single dose of detomidine gel (0.04 mg/kg) or a placebo-171 horses were treated with the sublingual detomidine gel and 68 received the placebo. The procedures attempted included prepuce cleaning, hair clipping, hoof trimming or shoeing, manual dental floating, passing of a nasogastric tube or endoscope, and radiography. Veterinarians were asked to rate various parameters related to the use of the sublingual gel including ease of proper administration, degree of sedation and ataxia produced, any adverse reactions, and the ability to attempt or complete the desired procedure.

In most cases, the veterinarian administered the gel, but in some cases either a technician or caregiver dosed the horses. The horses were assessed before drug administration, again about 40 minutes after treatment (a time period determined in previous studies), and periodically until the horse had completely recovered. Physical examination findings were recorded, and the ability to complete the procedure attempted was documented. All of the horses were allowed to recover quietly, and owners were interviewed two to four days later to determine if any adverse effects had occurred.

The gel administration (supplied as a blue gel in a graduated syringe at 7.6 mg/ml) proved to be relatively easy to accomplish; 76% of the horses receiving detomidine gel were sedated adequately for the procedure to be completed. Additionally, 19% of the treated horses never developed ataxia, and, for those that did, the ataxia was mild. Hair clipping proved to be the most difficult procedure to accomplish with the level of sedation achieved, which is not surprising as this type of drug does not dull responses to touch and noise effectively. The only adverse effects recorded were typical of alpha-2-agonists (decreased heart and respiratory rates, irregular heart rhythm consistent with second degree atrioventricular block) and resolved with recovery from sedation. Given the bright-blue color of the gel, it was easy to detect and wash off in cases of human contact. No adverse human reactions were noted during the study.

Significant variables intentionally were included in this study, such as the skill and training of those administering the medication and the type and duration of the procedures attempted. The results of this study suggest that in the real world setting of equine veterinary practice, detomidine gel may prove to be a safe, easy-to-administer addition to the equine chemical restraint arsenal.

Gardner RB, White GW, Ramsey DS, et al. Efficacy of sublingual administration of detomidine gel for sedation of horses undergoing veterinary and husbandry procedures under field conditions. J Am Vet Med Assoc 2010;237(12):1459-1464.

Link to abstract: http://avmajournals.avma.org/doi/abs/10.2460/javma.237.12.1459