Allergic reactions to brimonidine in patients treated for glaucoma.

BACKGROUND: Allergic reactions to ophthalmic drugs have not been studied extensively in ophthalmology. We performed a study to estimate the incidence of allergy to brimonidine in patients treated for glaucoma.

METHODS: We identified all patients in a private glaucoma practice who started therapy with brimonidine between Mar. 19, 1998, and Aug. 14, 1999. We recorded the patient's diagnosis, age, sex, concomitant glaucoma medication, previous allergy to glaucoma medication and allergy to brimonidine. Allergy was defined as allergic contact dermatoconjunctivitis or follicular conjunctivitis.

RESULTS: Of the 140 patients identified, 36 (25.7%) had had an allergic reaction to brimonidine. Contact dermatoconjunctivitis was noted in 19 patients (52.8%) and follicular conjunctivitis in 18 (50.0%). The rate of development of those two manifestations was linear and almost parallel throughout the study period. In logistic regression analysis previous allergy to a topically given antiglaucoma medication (t = -5.13) and concurrent use of levobunolol (t = 3.46) were retained as the most probable predictor variables of allergy to brimonidine. Life-table analysis showed a fairly linear curve, with no peak in allergy rate. Allergic reactions occurred throughout the year, with a small peak in March.

INTERPRETATION: We found a rate of allergy to brimonidine of 25.7%. Concomitant levobunolol use and allergy to another glaucoma medication were associated with a higher allergy rate.