Effect of different dose schedules of travoprost on intraocular pressure and pupil size in the glaucomatous Beagle.
OBJECTIVE
To evaluate changes in intraocular pressure and pupil size in glaucomatous dogs after instillation of 0.004% travoprost once in the morning, or once in the evening, or twice daily in 5-day multiple dose studies.


METHODS
Applanation tonometry (IOP) and pupil size (PS) measurements were obtained at 8 a.m., 10 a.m., 12 noon, 2 p.m. and 4 p.m. in eight glaucoma dogs. Methylcellulose (0.5% as placebo) was instilled in the control eye, and 0.004% travoprost was instilled in the opposite drug eye. Methylcellulose (0.5%) and 0.004% travoprost were instilled on the 2nd through to the 5th day with instillations in the morning (8.30 a.m.), or evening (8 p.m.), or twice daily (8.30 a.m. and 8 p.m.).


RESULTS
The mean +/- SEM diurnal changes from baseline IOP in the control and placebo eyes in all three studies ranged from 1.2 +/- 0.3 mmHg to 3.2 +/- 0.9 mmHg. The mean +/- SEM diurnal changes from the baseline IOP after 0.004% travoprost at 8 a.m. once daily for the next 4 days were 19.0 +/- 2.7 mmHg, 24.7 +/- 2.7 mmHg, 24.9 +/- 3.1 mmHg, and 24.7 +/- 3.1 mmHg, respectively, and were significantly different from the control eye. After travoprost was instilled at 8 p.m., the mean +/- SEM baseline changes from the baseline IOP in the drug eyes were 23.5 +/- 2.2 mmHg, 24.2 +/- 2.2 mmHg, 24.5 +/- 2.3 mmHg, and 24.2 +/- 2.3 mmHg, respectively. When 0.004% travoprost was instilled twice daily, the mean +/- SEM baseline IOP changes were 27.7 +/- 2.1 mmHg, 28.1 +/- 2.1 mmHg, 28.4 +/- 2.2 mmHg, and 28.5 +/- 2.2 mmHg, respectively, and were significantly different from the control eyes. Miosis of varying duration was frequent during the three studies.


CONCLUSIONS
Travoprost instilled once daily (a.m. or p.m.) as well as twice daily produces significant decreases in IOP and PS in the glaucomatous Beagle.
Gelatt
Kirk N
KN
Department of Small Animal Clinical Sciences and Gwathmey-Adams Laboratory for Vision Science, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0126, USA. Gelattk@mail.vetmed.ufl.edu
MacKay
Edward O
EO
D000287:Administration, Topical; D000818:Animals; D003008:Cloprostenol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000627:therapeutic use; D004283:Dog Diseases / Q000188:drug therapy* / Q000473:pathology; D004285:Dogs; D004334:Drug Administration Schedule; D005260:Female; D005901:Glaucoma / Q000188:drug therapy / Q000662:veterinary*; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D008365:Manometry / Q000662:veterinary; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D011680:Pupil / Q000187:drug effects*; D012720:Severity of Illness Index; D000069557:Travoprost
D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic; D003008:Cloprostenol; D000069557:Travoprost