Effects of topical application of a 2% solution of dorzolamide on intraocular pressure and aqueous humor flow rate in clinically normal dogs.
OBJECTIVE
To evaluate effects of topical application of a 2% solution of dorzolamide on intraocular pressure (IOP) and aqueous humor flow rate in clinically normal dogs.


METHODS
15 Beagles.


METHODS
The IOP was measured in both eyes of all dogs for 3 days to determine baseline values. In a single-dose study, 50 microl of dorzolamide or control solution was applied in both eyes at 7:00 AM, and IOP was measured 7 times/d. In a multiple-dose study, dorzolamide or control solution was applied to both eyes 3 times/d for 6 days, and IOP was measured 4 times/d during treatment and for 5 days after cessation of treatment. Aqueous humor flow rate was measured for all dogs fluorophotometrically prior to treatment and during the multiple-dose study.


RESULTS
In the single-dose study, dorzolamide significantly decreased IOP from 30 minutes to 6 hours after treatment. Mean decrease in IOP during this time span was 3.1 mm Hg (18.2%). Maximal decrease was detected 6 hours after treatment (3.8 mm Hg, 22.5%). In the multiple-dose study, dorzolamide decreased IOP at all time points, and maximal decrease was detected 3 hours after treatment (4.1 mm Hg, 24.3%). Mean aqueous humor flow rate decreased from 5.9 to 3.4 microl/min (43%) after treatment in the dorzolamide group.


CONCLUSIONS
Topical application of a 2% solution of dorzolamide significantly decreases IOP and aqueous humor flow rate in clinically normal dogs. Therefore, topical administration of dorzolamide should be considered for the medical management of dogs with glaucoma.
Cawrse
M A
MA
The Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville 37901, USA.
Ward
D A
DA
Hendrix
D V
DV
D000287:Administration, Topical; D000818:Animals; D001082:Aqueous Humor / Q000187:drug effects* / Q000502:physiology; D002257:Carbonic Anhydrase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D004285:Dogs / Q000502:physiology*; D005260:Female; D015590:Fluorophotometry / Q000662:veterinary; D005901:Glaucoma / Q000188:drug therapy / Q000662:veterinary; D007429:Intraocular Pressure / Q000187:drug effects* / Q000502:physiology; D008297:Male; D011897:Random Allocation; D013449:Sulfonamides / Q000008:administration & dosage / Q000494:pharmacology*; D013876:Thiophenes / Q000008:administration & dosage / Q000494:pharmacology*
D002257:Carbonic Anhydrase Inhibitors; D013449:Sulfonamides; D013876:Thiophenes; C062765:dorzolamide