Effects of topical administration of 0.005% latanoprost solution on eyes of clinically normal horses.
OBJECTIVE
To determine the effect of 0.005% latanoprost solution on intraocular pressure (IOP) of eyes of clinically normal horses and establish the frequency of adverse effects of drug administration.


METHODS
20 adult clinically normal horses.


METHODS
IOP was recorded (7, 9, and 11 AM; 3, 5, and 7 PM) on days 1 and 2 (baseline), days 3 to 7 (treatment), and days 8 to 9 (follow-up). Latanoprost was administered to 1 randomly assigned eye of each horse every 24 hours during the treatment period, following the 7 AM IOP recording. Pupil size and the presence or absence of conjunctival hyperemia, epiphora, blepharospasm, blepharedema, and aqueous flare were recorded prior to IOP measurement.


RESULTS
IOP was reduced from baseline by a mean value of 1.03 mm Hg (5%) in males and 3.01 mm Hg (17%) in females during the treatment period. Miosis developed in all treated eyes and was moderate to marked in 77% of horses, with the peak effect observed 4 to 8 hours after drug administration. Conjunctival hyperemia, epiphora, blepharospasm, and blepharedema were present in 100, 57, 42, and 12% of treated eyes, respectively, 2 to 24 hours following drug administration. Aqueous flare was not observed at any time point.


CONCLUSIONS
Although IOP was reduced with every 24-hour dosing of latanoprost, the frequency of prostaglandin-induced adverse events was high. Because recurrent uveitis appears to be a risk factor for glaucoma in horses, topical administration of latanoprost may potentiate prostaglandin-mediated inflammatory disease in affected horses.
Willis
A M
AM
Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus 43210, USA.
Diehl
K A
KA
Hoshaw-Woodard
S
S
Kobayashi
I
I
Vitucci
M P
MP
Schmall
L M
LM
D000287:Administration, Topical; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D006736:Horses / Q000502:physiology*; D007429:Intraocular Pressure / Q000187:drug effects*; D000077338:Latanoprost; D008297:Male; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic / Q000008:administration & dosage* / Q000009:adverse effects; D011897:Random Allocation; D012044:Regression Analysis; D014065:Tonometry, Ocular / Q000662:veterinary
D000959:Antihypertensive Agents; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic; D000077338:Latanoprost