The effects of dopamine, haloperidol and bromocriptine on intraocular pressure

In a double-blind randomised, prospective single dose study, we measured intraocular pressure (IOP), pupil diameter, systemic blood pressure and heart rate in 43 ocular normotensive subjects before (baseline) and 2, 4, and 6 hours after topical instillation of the following drugs: dopamine 2% (n = 11), a dopamine receptor blocking drug, haloperidol 0.5% (n = 11), a dopamine receptor stimulating drug, bromocriptine 0.05% (n = 11) and 0.1% (n = 10). In the groups receiving dopamine or haloperidol, there were no significant differences in IOP compared with baseline values (p > 0.01). But, a significant decrease in IOP compared with the baseline values was found in both bromocriptine groups (p < 0.001). With the 0.05% and 0.1% concentrations, maximum reductions in intraocular pressure were 22.0% +/- 5.8% and 28.4% +/- 9.8%, respectively. No significant differences in mean pupil diameter, systemic blood pressure and heart rate were detected in all of these groups. In addition, in the group receiving bromocriptine 0.1%, there was no change in serum prolactin levels. These results suggest that topically administered bromocriptine has satisfactory intraocular pressure lowering capacity without serious ocular or systemic side effects. Consequently we conclude that, an ophthalmic formulation of bromocriptine may have substantial clinical potential for the treatment of glaucoma.