EFFECT OF INTRAVENOUS FENOLDOPAM ON INTRAOCULAR-PRESSURE IN OCULAR HYPERTENSION

Intravenous fenoldopam, a selective dopamine-1 receptor agonist, was c ompared with placebo in this randomized, double-blind, two-period cros sover study to evaluate its effects on intraocular pressure, aqueous d ynamics, and macular blood flow in patients with elevated intraocular pressure or primary open-angle glaucoma. Doses of fenoldopam were titr ated up to a maximum of 0.5 mu g/kg/min. Intraocular pressure, measure d by pneumotonometry, was the primary outcome variable. Other outcomes included macular blood flow assessed by blue field examination, visua l field examined by automated perimetry, aqueous outflow facility meas ured by tonography, and aqueous humor production determined by fluorop hotometry. During infusions of fenoldopam, intraocular pressure increa sed from a mean baseline level of 29.2 mmHg to a mean maximum level of 35.7 mmHg. During the placebo infusions, pressure increased from a me an baseline of 28.4 mmHg to a mean of 29.0 mmHg at the time point that corresponded to the mean maximum intraocular pressure on the day intr avenous fenoldopam was administered, to yield a mean difference in pre ssure between study days of 6.7 mmHg (P < 0.05). There were no apparen t changes in macular blood flow, visual fields, or production or outfl ow of aqueous humor associated with fenoldopam infusion. The increase in intraocular pressure seen in this population of patients with ocula r hypertension during infusions of fenoldopam is consistent with fenol dopam-associated increases in intraocular pressure reported in previou s studies of healthy volunteers and of patients with accelerated syste mic hypertension. These results further suggest that dopamine-1 recept ors play a role in the regulation of intraocular pressure.