The determination of additive effect and intraocular pressure lowering effects of 0.05% bromocriptine and 0.25% timolol
It has been confirmed that topically applied bromocriptine has a satisfactory intraocular pressure (IOP) lowering effect without serious ocular or systemic side effects. We compared the IOP lowering effects of 0.05% bromocriptine and 0.25% timolol and determined whether they have an additive effect in lowering IOP in normal volunteers. In a double-blind, randomised, prospective, single-dose study, we measured IOP in 24 ocular normotensive subjects before (baseline) and 2, 4 and 6 hours after topical instillation of the following drugs: timolol and bromocriptine alone (n : 14), timolol + bromocriptine, timolol + placebo, bromocriptine + placebo (n : 10). Both bromocriptine and timolol have a significant IOP lowering effect (P < 0.01) compared with the baseline value during the study period. There were no significant differences in IOP lowering effect between timolol and bromocriptine at 2 and 4 hours (P > 0.05), but timolol was more efficacious than bromocriptine at 6 hours (p < 0.05). An additive effect in lowering IOP was not found. Although timolol and bromocriptine have no additive effect in lowering IOP, topically applied bromocriptine may be used in the treatment of glaucoma.