Effect of intramuscular administration of medetomidine and xylazine on tear flow measured by the Schirmer tear test I in healthy cats. Issue 8 (August 2019)

• Record Type: Journal Article
• Authors: Kanda, Teppei; Shimizu, Yuki; Hanazono, Chisa; Maki, Saya; Maeta, Noritaka; Itoi, Takamasa; Furumoto, Kayo; Okamura, Yasuhiko; Itoh, Yoshiki; Furukawa, Toshinori
• Is Part Of: Journal of feline medicine and surgery. Volume 21:Issue 8(2019)
• Page Start: 788
• Page End: 792
• Publication Date: 2019-08
• Subjects: Medetomidine -- xylazine -- Schirmer tear test; Cats -- Diseases -- Periodicals; Cats -- Surgery -- Periodicals; 636.8089
• DOI: 10.1177/1098612X18795723
• Languages: English
• ISSNs: 1098-612X

Abstract

Objectives: This study aimed to investigate the effects of intramuscular medetomidine and xylazine on tear flow in healthy cats. Methods: Five cats each received medetomidine 10, 20, 40 and 80 µg/kg IM; xylazine 1.0, 2.0, 4.0 and 8.0 mg/kg IM; and physiological saline (2.0 ml IM) in a randomised order separated by intervals of at least 1 week. The Schirmer tear test (STT) I was performed in both eyes before and 0.25, 0.5, 0.75, 1, 2, 3, 4, 5, 6, 7, 8 and 24 h after each dose. Results: The STT I value decreased significantly at 0.5 and 1.0 h and at 0.75 and 1.0 h in both eyes after administration of medetomidine at 10 or 40 µg/kg. After administration of medetomidine 80 µg/kg, there was a significant decrease in the STT I reading at 0.75, 2 and 3 h in the left eye and 0.75, 1, 2 and 3 h in the right eye. The STT I value decreased significantly at: 0.5, 0.75, 1 and 2 h in the left eye and 0.75 h in the right eye after administration of xylazine 1.0 mg/kg; 0.5, 0.75, 1 and 2 h in the left eye and 0.5, 0.75, 1 and 3 h in the right eye after administration of xylazine 2.0 mg/kg; 0.5, 0.75, 1 and 2 h in both eyes after administration of xylazine 4.0 mg/kg; and 0.5, 0.75, 1, 2 and 3 h in the left eye and 0.75, 1, 2, 3 and 4 h in the right eye after administration of xylazine 8.0 mg/kg. Conclusions and relevance: Both medetomidine and xylazine significantly decreased feline tear flow measured by STT I. Therefore, the ocular surface should be monitored carefully and protected appropriately in cats treated with these sedatives.