A clinical trial of metipranolol, a noncardioselective beta-adrenergic antagonist, in ocular hypertension

In randomized, double-masked fashion, 24 volunteers with ocular hypertension received 0.3% or 0.6% metipranolol, a noncardioselective beta blocker; or placebo twice daily to both eyes for six weeks. Intraocular pressure (mean ± SEM) was reduced (P = .01) in the metipranolol-treated patients (baseline measurement, 25.9 ± 0.5 mm Hg to 18.1 ± 1.2 mm Hg at six weeks, 0.6% concentration; baseline measurement, 27.1 ± 0.4 mm Hg to 21.6 ± 1.5 mm Hg at six weeks, 0.3% concentration). Intraocular pressure was not markedly changed in placebo-treated patients. Outflow facility was unaltered two hours after instillation of metipranolol at study week 2 compared to baseline measurement. Aqueous humor flow rates were reduced (P = .02) 20% after 0.6% or 0.3% metipranolol instillation and were unchanged after placebo administration compared to baseline measurement. Mean systolic blood pressure, diastolic blood pressure, and pulse rate were not markedly altered. Metipranolol reduces intraocular pressure by suppressing aqueous humor flow rates.