Ibopamine, dopamine and IOP

Ibopamine is a pro-drug of epinine, a dopamine analogue, which stimulates dopaminergic, beta-adrenergic and, at high concentrations, alpha-adrenergic receptors. On the basis of the results obtained by the authors since 5 years, ibopamine administered topically at a concentration of 2% owns the property of determining, besides a marked mydriasis without cycloplegia, an ocular hypertensiue activity lasting 1 to 2 hours, in 92% of patients with high-tension open-angle glaucoma, in 34% of subjects with borderline IOP and in 76% of patients with normal pressure glaucoma. No significant IOP changes were noted in normal eyes. The IOP responses proved to be independent from the mydriasis induced by the drug. These data speak in favour of the clinical application of ibopamine as a valuable provocative test in glaucoma. The ocular hypertensive effects of ibopamine are attributable to a dopaminergic action, since the topical administration of adequate concentrations of dopamine (ocular bath) induced similar IOP responses in the same glaucomatous patients previously treated with ibopamine. The authors discuss their clinical data obtained in a six-year experience with dopamine, ibopamine and several D1 and D2 agonists and antagonists in order to point out the role played by the dopaminergic system in the IOP-physiopathology.