{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T15:02:37Z","timestamp":1789138957030,"version":"build-2803163510"},"reference-count":48,"publisher":"American Veterinary Medical Association (AVMA)","issue":"12","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["ajvr"],"published-print":{"date-parts":[[2020,12]]},"abstract":"Abstract<\/jats:title>\n\nOBJECTIVE<\/jats:title>\nTo determine the effects of gabapentin, tramadol, and meloxicam on tear production, intraocular pressure (IOP), pupillary diameter, tear break-up time, and corneal touch threshold in healthy dogs when given orally for 3 days.<\/jats:p>\n<\/jats:sec>\n\nANIMALS<\/jats:title>\n9 healthy research Beagles.<\/jats:p>\n<\/jats:sec>\n\nPROCEDURES<\/jats:title>\nA randomized, blinded, case-crossover study with a 6-sequence, 3-treatment, and 3-period design was performed. A 7-day acclimation period was followed by 3 treatment phases, each with a 3-day treatment period followed by a 7-day washout period for 3 different drugs. Block randomization was used to group dogs for treatments with drug A (gabapentin), B (tramadol), or C (meloxicam). Measurements of tear production, IOP, pupillary diameter, tear break-up time, and corneal touch threshold were performed on a schedule. A generalized mixed-effects linear regression model was created for each ocular variable, accounting for repeated measures within individuals.<\/jats:p>\n<\/jats:sec>\n\nRESULTS<\/jats:title>\nIntraocular pressure was the only variable to have differed substantially between the first 5 and last 2 days of the acclimation period. When treatment phase, day, time of day, dog identification, baseline value, and eye were accounted for, the mean IOP was lower for dogs during treatment phases with gabapentin or tramadol, compared with meloxicam, but this difference was not considered clinically meaningful.<\/jats:p>\n<\/jats:sec>\n\nCONCLUSIONS AND CLINICAL RELEVANCE<\/jats:title>\nResults indicated that a minimum 5-day acclimation period is necessary for IOP measurements to return to baseline in dogs. The statistically identified effect of gabapentin and tramadol on IOP in dogs of the present study warrants further investigation. It is possible that at higher dosages, or in dogs with glaucoma, this effect may become clinically significant.<\/jats:p>\n<\/jats:sec>","DOI":"10.2460\/ajvr.81.12.973","type":"journal-article","created":{"date-parts":[[2020,11,30]],"date-time":"2020-11-30T13:28:37Z","timestamp":1606742917000},"page":"973-984","source":"Crossref","is-referenced-by-count":12,"title":["Effects of orally administered gabapentin, tramadol, and meloxicam on ocular variables in healthy dogs"],"prefix":"10.2460","volume":"81","author":[{"given":"Angelie K.","family":"Shukla","sequence":"first","affiliation":[{"name":"1Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chantale L.","family":"Pinard","sequence":"additional","affiliation":[{"name":"1Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, 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Ophthalmol","doi-asserted-by":"publisher","first-page":"27","DOI":"10.1111\/vop.12340","article-title":"Intracorneal stromal hemorrhage in dogs and its associations with ocular and systemic disease: 39 cases","volume":"20","author":"Violette","year":"2017"},{"key":"ref7","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"233","DOI":"10.1111\/vop.12496","article-title":"Punctate retinal hemorrhage and its relation to ocular and systemic disease in dogs: 83 cases","volume":"21","author":"Violette","year":"2018"},{"key":"ref8","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"390","DOI":"10.1111\/vop.12437","article-title":"Canine panuveitis: a retrospective evaluation of 55 cases (2000\u20132015)","volume":"20","author":"Bergstrom","year":"2017"},{"key":"ref9","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"305","DOI":"10.1111\/vop.12304","article-title":"Diamond burr debridement of 34 canine corneas with presumed corneal calcareous degeneration","volume":"19","author":"Nevile","year":"2016"},{"key":"ref10","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"481","DOI":"10.1111\/vop.12237","article-title":"Effect of tiletamine-zolazepam on the intraocular pressure of the dog","volume":"18","author":"Jang","year":"2015"},{"key":"ref11","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"33","DOI":"10.1111\/j.1463-5224.2005.00432.x","article-title":"Effects of medetomidine and medetomidine-butorphanol combination on Schirmer tear test 1 readings in dogs","volume":"9","author":"Sanchez","year":"2006"},{"key":"ref12","series-title":"Comp Clin Pathol","doi-asserted-by":"publisher","first-page":"413","DOI":"10.1007\/s00580-010-1135-x","article-title":"Effects of intramuscular chlorpromazine alone and chlorpromazine\u2013morphine combination on Schirmer tear test results in clinically normal dogs","volume":"20","author":"Ghaffari","year":"2011"},{"key":"ref13","series-title":"Vet Rec","doi-asserted-by":"publisher","first-page":"564","DOI":"10.1136\/vr.155.18.564","article-title":"Effects of pethidine and fentanyl on tear production in dogs","volume":"155","author":"Biricik","year":"2004"},{"key":"ref14","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"57","DOI":"10.1046\/j.1463-5224.1998.00005.x","article-title":"Effects of intramuscular sedative and opioid combinations on tear production in dogs","volume":"1","author":"Dodam","year":"1998"},{"key":"ref15","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"358","DOI":"10.1111\/j.1463-5224.2011.00883.x","article-title":"Evaluation of topical nalbuphine or oral tramadol as analgesics for corneal pain in dogs: a pilot study: nalbuphine and tramadol for corneal analgesia","volume":"14","author":"Clark","year":"2011"},{"key":"ref16","series-title":"Plumb's veterinary drug handbook","first-page":"528","article-title":"Gabapentin, tramadol, meloxicam","author":"Plumb","year":"2017"},{"key":"ref17","series-title":"Front Pharmacol","first-page":"1","article-title":"Gabapentin attenuates ocular inflammation: in vitro and in vivo studies","volume":"8","author":"Anfuso","year":"2017"},{"key":"ref18","series-title":"J Pharmacol Exp Ther","first-page":"275","article-title":"Opioid and nonopioid components independently contribute to the mechanism of action of tramadol, an \u2018atypical\u2019 opioid analgesic","volume":"260","author":"Raffa","year":"1992"},{"key":"ref19","series-title":"Am J Vet Res","doi-asserted-by":"publisher","first-page":"256","DOI":"10.2460\/ajvr.72.2.256","article-title":"Pharmacokinetics and antinociceptive effects of oral tramadol hydrochloride administration in Greyhounds","volume":"72","author":"KuKanich","year":"2011"},{"key":"ref20","series-title":"BMC Vet Res","doi-asserted-by":"publisher","first-page":"288","DOI":"10.1186\/s12917-017-1206-1","article-title":"Effects of premedication with oral gabapentin on intraocular pressure changes following tracheal intubation in clinically normal dogs","volume":"13","author":"Trbolova","year":"2017"},{"key":"ref21","series-title":"Cienc Rural","doi-asserted-by":"publisher","first-page":"724","DOI":"10.1590\/0103-8478cr20140826","article-title":"Effects of tramadol on tear production, intraocular pressure, and pupil size in dogs: clinical study","volume":"45","author":"Ruiz","year":"2015"},{"key":"ref22","series-title":"J Vet Pharmacol Ther","doi-asserted-by":"publisher","first-page":"344","DOI":"10.1111\/jvp.12294","article-title":"Effect of oral administration of carprofen on intraocular pressure in normal dogs","volume":"39","author":"Meekins","year":"2016"},{"key":"ref23","series-title":"Veterinary epidemiologic 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dogs without glaucoma","volume":"69","author":"Broadwater","year":"2008"},{"key":"ref28","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"140","DOI":"10.1111\/vop.12487","article-title":"Effect of body position, eyelid manipulation, and manual jugular compression on intraocular pressure in clinically normal cats","volume":"21","author":"Rajaei","year":"2018"},{"key":"ref29","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"7","DOI":"10.1046\/j.1463-5224.2001.00124.x","article-title":"Estimation of lacrimal level and testing methods on normal Beagles","volume":"4","author":"Saito","year":"2001"},{"key":"ref30","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"20","DOI":"10.1111\/vop.12101","article-title":"Clinical comparison of the TonoVet \u00ae rebound tonometer and the Tono-Pen Vet \u00ae applanation tonometer in dogs and cats with ocular disease: glaucoma or corneal pathology","volume":"18","author":"von Spiessen","year":"2015"},{"key":"ref31","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"411","DOI":"10.1111\/vop.12119","article-title":"A comparison of alfaxalone and propofol on intraocular pressure in healthy dogs","volume":"17","author":"Hasiuk","year":"2014"},{"key":"ref32","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"71","DOI":"10.1111\/j.1463-5224.2010.00832.x","article-title":"Effect of topical 0.03% flurbiprofen and 0.005% latanoprost, alone and in combination, on normal canine eyes: effect of flurbiprofen and latanoprost on canine eyes","volume":"14","author":"Pirie","year":"2011"},{"key":"ref33","series-title":"Invest Ophthalmol Vis Sci","doi-asserted-by":"publisher","first-page":"65","DOI":"10.1167\/iovs.16-19865","article-title":"Assessment of rod, cone, and intrinsically photosensitive retinal ganglion cell contributions to the canine chromatic pupillary 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Res","doi-asserted-by":"publisher","first-page":"608","DOI":"10.2460\/ajvr.72.5.608","article-title":"Effect of duration and type of anesthetic on tear production in dogs","volume":"72","author":"Shepard","year":"2011"},{"key":"ref41","series-title":"J Am Anim Hosp Assoc","doi-asserted-by":"publisher","first-page":"79","DOI":"10.5326\/15473317-34-1-79","article-title":"The fluctuation of tear production in the dog","volume":"34","author":"Berger","year":"1998"},{"key":"ref42","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"53","DOI":"10.1111\/j.1463-5224.2005.00437.x","article-title":"Effect of age, gender, weight, and time of day on tear production in normal dogs","volume":"9","author":"Hartley","year":"2006"},{"key":"ref43","series-title":"Physiol Meas","doi-asserted-by":"publisher","first-page":"89","DOI":"10.1088\/1361-6579\/aa6782","article-title":"An introduction into autonomic nervous function","volume":"38","author":"Karemaker","year":"2017"},{"key":"ref44","series-title":"Invest Ophthalmol Vis Sci","doi-asserted-by":"publisher","first-page":"5432","DOI":"10.1167\/iovs.13-12012","article-title":"Quantitative assessment of the canine pupillary light reflex","volume":"54","author":"Whiting","year":"2013"},{"key":"ref45","series-title":"Vet Ophthalmol","doi-asserted-by":"publisher","first-page":"160","DOI":"10.1111\/vop.12386","article-title":"The effects of topical diclofenac, topical flurbiprofen, and humidity on corneal sensitivity in normal dogs","volume":"20","author":"Dorbandt","year":"2017"},{"key":"ref46","series-title":"Top Companion Anim Med","doi-asserted-by":"publisher","first-page":"109","DOI":"10.1053\/j.tcam.2011.02.003","article-title":"Common laboratory artifacts caused by inappropriate sample collection and transport: how to get the most out of a sample","volume":"26","author":"Gilor","year":"2011"},{"key":"ref47","series-title":"Int J Pharm 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