Cardiovascular effects of epinephrine and dipivefrin in patients using timolol: a single-dose study

Timolol and epinephrine may have cardiovascular effects when used alone topically. These drugs are partial pharmacologic antagonists at the adrenergic beta-receptor. When a placebo, 2% epinephrine hydrochloride or 0.1% dipivefrin hydrochloride was instilled in a randomized, double-blind fashion in eyes treated with timolol maleate no change in heart rate, intraocular pressure or rate of aqueous outflow was noted. The systolic blood pressure did not increase, but with epinephrine a slight increase in diastolic blood pressure was noted. Moreover, cardiac arrhythmias appeared after the use of epinephrine. The pupil enlarged after the instillation of epinephrine or dipivefrin.