title: Effects of intramuscular sedative and opioid combinations on tear production in dogs.
abstract: The effect of commonly used sedation protocols on tear production rate was evaluated in dogs. Schirmer I tear tests were examined before and after intramuscular injection of acepromazine and oxymorphone (ACE + OXY; n = 7), diazepam and butorphanol (DIA + BUT; n = 8), and xylazine and butorphanol (XYL + BUT; n = 8). Two Schirmer I tear tests were also performed 15-25 min apart in dogs which received no sedative drugs (control; n = 4). Tear production rate decreased to 15 +/- 2, 17 +/- 1, and 6 +/- 1 mm min-1, respectively, while control animals averaged 21 +/- 2 mm min-1 at the same time point. Because XYL + BUT profoundly decreased tear production rate, we evaluated the two drugs separately. While BUT mildly decreased tear production when given alone to dogs (18 +/- 1 mm min-1; n = 5), xylazine had no effect on tear production. Thus it appears that the two agents act synergistically to decrease tear production rate in dogs. Moreover, sterile ocular lubricant or tear replacement should be used during XYL + BUT sedation.
authors.affiliation: Department of Veterinary Medicine and Surgery at the College of Veterinary Medicine, University of Missouri, 379 East Campus Drive, Columbia, MO 65211, USA; Veterinary Biomedical Sciences at the College of Veterinary Medicine, University of Missouri, 379 East Campus Drive, Columbia, MO 65211, USA; Department of Veterinary Clinical Sciences, School of Veterinary Medicine, 1240 Lynn Hall, Purdue University, West Lafayette, IN 47906, USA.
authors.forename: J.R.
authors.initials: JR
authors.lastname: Dodam
authors.forename: K.R.
authors.initials: KR
authors.lastname: Branson
authors.forename: D.D.
authors.initials: DD
authors.lastname: Martin