Effects of topical administration of 1% brinzolamide on normal cat eyes.

OBJECTIVE: To evaluate the effect of short-term daily topical administration of 1% brinzolamide on the intraocular pressure (IOP) of healthy domestic cats with normotensive eyes and to assess the potential for negative side effects of drug administration. ANIMALS: Twelve privately owned adult domestic cats without physical or ocular abnormalities. PROCEDURE: Normal variation in IOP was determined on day 1. Cats were then treated on days 2-8 with a topical placebo (artificial tear solution) OU q 12 h. On days 9-15 the cats were treated q 12 h with 1% brinzolamide in one randomly selected eye and the placebo in the contralateral eye. All medications (drug and placebo) were administered twice daily at 7 a.m. and 7 p.m. On days 16-22 the cats received no topical medications. IOP, horizontal pupil size in mm and assessment of conjunctival hyperemia were noted OU on days 1, 8, 15 and 22 at 5 time points (9 a.m., 11 a.m., 1 p.m., 3 p.m. and 5 p.m.). Mixed linear regression models were used to compare the IOP of each eye at all time periods for each cat, controlling for age and weight.
RESULTS: Mean IOP was not significantly altered in any eye at any time point during the treatment period compared with pretreatment, baseline, or follow-up evaluations. Conjunctival hyperemia and miosis were not detected in either eye at any time point. Conclusions and clinical relevance Short-term q 12 h administration of 1% brinzolamide did not significantly reduce IOP in this small sample population of normotensive cats under these study conditions. No clinically relevant side effects were noted with brinzolamide administration.