• The interaction of adrenergic β-receptor blockers and epinephrine on intraocular pressure and pupil size was investigated in healthy volunteers. Oral (atenolol and propranolol) and local (timolol) β-blockers were studied. The experiment was carried out under doubleblind randomized crossover conditions. The results showed that the combination of oral β-blockers with topical epinephrine had an additive hypotensive effect on IOP, while timolol and epinephrine eyedrops both reduced the IOP used alone, but combined had an antagonistic effect, resulting in the disappearance of the epinephrine-mediated IOP reduction.
Önrström A, Pandolfi M. Regulation of Intraocular Pressure and Pupil Size by β-Blockers and Epinephrine. Arch Ophthalmol. 1980;98(12):2182-2184. doi:10.1001/archopht.1980.01020041034005