Timolol and epinephrine: a clinical study of ocular interactions.
In a crossover design study, we assessed effects on intraocular pressure, pupillary diamter, pulse rate, and blood pressure over six hours of one drop of 0.5% timolol maleate and 2% epinephrine hydrochloride in one eye. Both eyes of each patient had been pretreated for one week with twice-daily applications pf epinephrine or timolol, respectively. In random sequence, 20 patients (40 eyes) participated in both phases of the study. Pretreatment with timolol significantly reduced the ocular hypotensive effect of epinephrine (from 15.3% to 4.6%); epinephrine pretreatment did not affect the pressure reduction of timolol. Pretreatment with timolol enhanced the mydriatic effect of epinephrine (from 35.8% to 71.9% pupillary dilation); pretreatment with epinephrine resulted in an apparent mydriatic effect for timolol.
D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D004347:Drug Interactions; D004837:Epinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D011412:Propanolamines / Q000494:pharmacology*; D011446:Prospective Studies; D011674:Pulse / Q000187:drug effects; D011680:Pupil / Q000187:drug effects*; D011897:Random Allocation; D013999:Timolol / Q000037:antagonists & inhibitors / Q000494:pharmacology*
D011412:Propanolamines; D013999:Timolol; D004837:Epinephrine