title: Enhanced ocular hypotensive response to epinephrine in rabbits with prior dexamethasone treatment.
abstract: The purpose of this study was to determine glucocorticoid modulation of ocular pressure to epinephrine applied topically to rabbit eyes that were pretreated with dexamethasone. Rabbit eyes were pretreated with five applications of topical 0.07% dexamethasone (0.1% dexamethasone phosphate) or saline drops, administered at ten minute intervals. The eyes were then treated with epinephrine bitartrate drops at concentrations of free base epinephrine of 1.1%, 0.27%, 0.05%, 0.027%, 0.005% or 0.0005%. An additional group of rabbits received dexamethasone pretreatment only. Intraocular pressure (IOP) was measured for the next four hours. Enhanced lowering of intraocular pressure was observed with dexamethasone pretreatment. Rabbits receiving the smaller dose of epinephrine with dexamethasone had the largest decrease in IOP at 135 minutes after instillation of the epinephrine drops (0.005% epinephrine, mean difference +/- standard error of mean = 5.4 +/- 1.1 mmHg). Similarly, the duration of significant decrease of the IOP was prolonged in the groups receiving the lower concentrations of epinephrine (0.005% epinephrine, 255 minutes after administration of epinephrine). The synergism between glucocorticoids and adrenergic agonists in lowering IOP may be potentially useful in the therapy of ocular hypertension and glaucoma.
authors.affiliation: New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Rom
authors.forename: B
authors.initials: B
authors.lastname: Schwartz
authors.forename: A L
authors.initials: AL
authors.lastname: Ungricht
authors.forename: W
authors.initials: W
authors.lastname: Lee
mesh_terms: D000287:Administration, Topical; D000322:Adrenergic Agonists / Q000008:administration & dosage*; D000818:Animals; D003907:Dexamethasone / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004837:Epinephrine / Q000008:administration & dosage*; D005938:Glucocorticoids / Q000008:administration & dosage*; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D015814:Ocular Hypotension / Q000139:chemically induced*; D009883:Ophthalmic Solutions; D011817:Rabbits
chemical_list: D000322:Adrenergic Agonists; D005938:Glucocorticoids; D009883:Ophthalmic Solutions; D003907:Dexamethasone; D004837:Epinephrine