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 μg/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 (T5 ), 15 (T15 ), 30 (T30 ), 45 (T45 ), 60 (T60 ), 90 (T90 ), and 120 (T120 ) 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 T5 , T15 , T30 , T45 , T60 , and T90 in comparison with the baseline values (P < 0.05). The lowest level of IOP in romifidine-treated groups was recorded at T45 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.