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Effects of topical 2% dorzolamide hydrochloride alone and in combination with 0.5% timolol maleate on intraocular pressure in normal feline eyes
Author(s) -
Dietrich Ursula M.,
Chandler Matthew J.,
Cooper Tanya,
Vidyashankar Anand,
Chen Guorong
Publication year - 2007
Publication title -
veterinary ophthalmology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.594
H-Index - 50
eISSN - 1463-5224
pISSN - 1463-5216
DOI - 10.1111/j.1463-5224.2007.00583.x
Subject(s) - dorzolamide , intraocular pressure , timolol , medicine , pharmacology , ophthalmology , hydrochloride , chemistry , biochemistry
Abstract Objective To evaluate the effect of topical 2% dorzolamide alone, and in combination with topical 0.5% timolol, on intraocular pressure (IOP) in normal cats. Animals Twenty‐four healthy Domestic Short‐haired cats. Procedure Baseline values of IOP were established at 7 am , 10 am , 1 pm , 5 pm and 9 pm during pretreatment phase (days 1–2). During treatment phase (days 3–10) cats received 2% dorzolamide HCl q 12 h in group A ( n = 6), q 8 h in group B ( n = 6), and combined with 0.5% timolol maleate q 12 h in group C ( n = 6). Cats in control group D ( n = 6) received artificial tears q 8 h. During treatment phase IOP measurements were continued at the same time‐points as in the pretreatment phase. Results Mean pretreatment IOP in all cats was 18.46 ± 2.99 mmHg. Mean IOP decreased significantly ( P < 0.0086) in all treatment groups compared to pretreatment values (group A: 16.40 ± 0.49 mmHg, group B: 16.04 ± 0.49 mmHg, group C: 17.76 ± 0.49 mmHg). IOP did not decrease in control group D (18.55 ± 0.49 mmHg). The difference in IOP between treatment groups (A, B, C) was not statistically significant, but comparison of IOP between each treatment group and the control group was statistically significant (A–D; P = 0.0057; B–D, P = 0.0012; C–D, P = 0.0212). Conclusion Topical 2% dorzolamide significantly lowers IOP in normal cats but the effect is mild. Concomitant application of 2% dorzolamide and 0.5% timolol does significantly decrease IOP, but the effect is not significantly greater than q 8 h administration of dorzolamide alone.