Metipranolol is a non-selective β-adrenergic receptor (β-AR) antagonist. It binds to primary rabbit iris and ciliary body homogenates (Ki = 34 nM) and inhibits relaxation induced by isoproterenol in guinea pig atrium and by fenoterol in rat uterus (pA2s = 8.3 and 8.4, respectively). In vitro, metipranolol (100 μM) inhibits anoxia-induced cell death in primary rat retinal cells and sodium nitroprusside-induced lipid peroxidation in rat primary retinal homogenates. In vivo, topical ocular application of metipranolol (0.3%) decreases α-chymotrypsin-induced increases in intraocular pressure (IOP) in rabbits. It also inhibits the blinking response to ocular tactile stimulation in rabbits when administered topically to the eye at a dose of 0.6%. Formulations containing metipranolol have been used in the treatment of elevated IOP in patients with ocular hypertension or glaucoma.