THE NOVEL DOPAMINE D-1 ANTAGONIST AND D-2 AGONIST, SDZ GLC-756, LOWERS INTRAOCULAR-PRESSURE IN HEALTHY-HUMAN VOLUNTEERS AND IN PATIENTS WITH GLAUCOMA

Purpose: To investigate the intraocular pressure (IOP)-reducing effect and side effects of SDZ GLC-756, a novel dopamine D-1 antagonist and D-2 agonist, in control subjects and patients with open-angle glaucoma or ocular hypertension.Methods: A single-application, randomized, pla cebo-controlled, double-masked study was performed. SDZ GLC-756 eye dr ops at a concentration of 0.01% (n = 6) or 0.1% (n = 6) were administe red to one eye in control subjects, vehicle alone (control) to the con tralateral eye. In glaucoma patients the trial was designed as a cross over study administering SDZ GLC-756 (0.1%) eye drops and vehicle alon e (control) to one eye in 12 patients with open-angle glaucoma or ocul ar hypertension. Results: In control subjects, IOP decreased significa ntly by 2.0 +/- 0.4 mmHg (P < 0.01) after treatment with 0.01% SDZ GLC -756 and by 4.7 +/- 0.5 mmHg (P < 0.001) after treatment with 0.1% SDZ GLC-756. In the glaucoma group, IOP decreased by 6.8 +/- 0.6 mmHg (P < 0.001) (range, 4-11 mmHg). In both groups, treatment with 0.1% eye d rops resulted in a significant IOP-lowering effect for 6 hours, and fo r 3 hours with treatment with 0.01% eye drops. A significant IOP-lower ing effect (P < 0.05) also was found in the contralateral eye. Except for slight conjunctival hyperemia lasting up to 30 minutes after drug application, no ocular or systemic side effects were observed. Conclus ion: SDZ GLC-756 reduced IOP significantly for approximately 6 hours. However, due to the study design with repeated IOP measurements before drug administration, the clinical efficacy of the preparation used re mains unclear. The only systemic or local side effect observed was sli ght conjunctival hyperemia. The simultaneous D-1 antagonistic and D-2 agonistic properties of SDZ GLC-756 may provide a new pharmacologic ap proach to treating glaucoma and ocular hypertension, which deserves fu rther investigation.