Purpose: To investigate the effects of single combined administration of brimonidine and ripasudil on intraocular pressure (IOP), pupil diameter (PD), and hyperemia.
Subjects and methods: The subjects comprised 20 right eyes of 20 healthy individuals (mean age: 40.8±11.6 years). A single instillation of brimonidine and/or ripasudil was performed at 9 am. IOP, PD, and hyperemia scores were measured prior to and 2, 4, and 8h after drug instillation using a Goldmann tonometer, autoref keratometer, and camera. There was a gap of at least 1 week between the studies. A mixed-effect model was used for the analyses of the IOP-lowering effects, pupil diameter, and hyperemia score changes in each of the groups.
Results: The IOP reduction in the combination group was significantly larger than those in the other groups at 2 and 4h (p＜0.01), but there was no significant difference at 8h. PD significantly decreased in the brimonidine and combination groups at 2, 4, and 8h (p＜0.001), and there was no difference between the amount of change. The hyperemia score in the combination group was significantly lower than that in the ripasudil group at 2h (p＝0.003).
Conclusions: The combination of brimonidine and ripasudil lowered IOP more than that by monotherapies at 2 and 4h after instillation, but not after 8h. Ripasudil did not have an additive effect on brimonidine for PD. Brimonidine may inhibit hyperemia when combined with ripasudil.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 122: 453-459, 2018.