Effect of topical naltrexone 0.3% on corneal sensitivity and tear parameters in normal brachycephalic dogs

Trevor S. Arnold, Luke Anthony Wittenburg, Cynthia C. Powell

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Objective: To determine the effect of topical naltrexone 0.3% on tear production, corneal sensitivity, and tear film stability in normal brachycephalic dogs. Animals Studied: Twenty-two normal brachycephalic dogs. Procedures: Measurements of tear production (Schirmer tear test I and II), intraocular pressure (IOP), central corneal sensitivity (CS), and tear film breakup time (TFBUT) were collected at time 0, 1, and 24 h after administration of either naltrexone (NTX) 0.3% or placebo (SV). Naltrexone or SV was then administered once daily for 1 week, and the above measurements were repeated at 7 days, then again 7 days after discontinuing medication. Owners scored the degree of comfort, redness, rubbing, squinting, and tearing. Serum was collected at time 0, 1, 24 h, and 7 days to determine systemic concentrations. Results: Owners reported no significant change in the degree of comfort, redness, rubbing, squinting, or tearing. Naltrexone was detected in serum of all treated dogs 1-h postadministration (average: 908 pg/mL, range: 319-1570 pg/mL) and in two dogs at the 1-week time point. Naltrexone was not detected at the 24-h time point. There was no significant effect of NTX on STT1, STT2, IOP, CS, or TFBUT. Conclusions: Naltrexone 0.3% is well tolerated and safe when applied topically to the eye once daily. Naltrexone 0.3% did not show any significant effects on corneal parameters as measured in this study. At once, daily dosing NTX is systemically absorbed; however, the degree of systemic absorption is not likely to be clinically significant.

Original languageEnglish (US)
Pages (from-to)328-333
Number of pages6
JournalVeterinary Ophthalmology
Volume17
Issue number5
DOIs
StatePublished - Sep 1 2014
Externally publishedYes

Keywords

  • Brachycephalic
  • Corneal sensitivity
  • Naltrexone
  • Opioid growth factor receptor
  • Opioid-like growth factor
  • Tear production

ASJC Scopus subject areas

  • veterinary(all)
  • Medicine(all)

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