Effect of intravenous administration of romifidine on intraocular pressure in clinically normal horses

Objective To evaluate the effect of intravenous administration of romifidine on the intraocular pressure (IOP) in horses. Animals studied Twenty-four horses with no ocular abnormalities. Procedure Horses were randomly assigned into two equal groups (treatment and control). All horses in the treatment group received an intravenous (IV) injection of romifidine (40 mu g/kg). The horses in the control group were administrated an intravenous injection of 0.9% saline (0.4 mL/100 kg). In both groups, the IOP values were measured immediately (T0) pre-administration and at 5 (T-5), 15 (T-15), 30 (T-30), 45 (T-45), 60 (T-60), 90 (T-90), and 120 (T-120) min after drug administration. Results The pre-treatment values (T0) of IOP for right and left eyes were 24.25 +/- 3.5 and 25.16 +/- 3.4 mmHg, respectively. A significant decrease in IOP values was observed in both right and left eyes of the horses in treatment group at T-5, T-15, T-30, T-45, T-60, and T-90 in comparison with the baseline values (P < 0.05). The lowest level of IOP in romifidine-treated groups was recorded at T-45 for the right and left eyes (10.25 +/- 2.3 and 11.25 +/- 3.5 mmHg, respectively). Conclusion Romifidine significantly decreased IOP in clinically normal horses and may be used safely for surgery or diagnostic ocular procedures in horses when specific control of IOP is required.