The idea of being able to "unsedate" or "reverse" a sedated horse after minor procedures is a great one, but veterinarians must select their cases carefully and be vigilant about using these drugs properly.

"The α-2 adrenergic agonists xylazine, detomidine, and romifidine are all commonly used sedatives in equine practice," relayed David B. Scofield, DVM, of Colorado State University’s College of Veterinary Medicine & Biomedical Sciences, during a presentation at the 2010 American Association of Equine Practitioners Convention, held Dec. 4-8 in Baltimore, Md. "Their effects can be reversed by such drugs as tolazoline and yohimbine."

Tolazoline is FDA-approved for horses and has been deemed a safe pharmacologic product: "Yohimbine is approved for use in dogs, so there is no label claim for the horse. Tolazoline is specifically labeled for the horse, therefore deemed safe for use in the horse."

To document the side effects associated with tolazoline or yohimbine in horses, Scofield and colleagues collected data from case reports on the AAEP e-mail distribution list and Equine Clinician’s distribution list in early 2010