Abstract
Purpose:
Ocular hyperemia is most commonly treated with vasoconstrictors that provide minimal short term relief. Alternative agents, with minimal side effects, that provide enhanced efficacy are highly sought after.
Methods:
Subjects (N=60) with a history of allergic conjunctivitis were enrolled in a randomized, single center, Conjunctival Allergen Challenge (CAC) based study to evaluate the safety and efficacy of brimonidine tartrate (BT) (0.01 and 0.025%) as compared with oxymetazoline (OM) 0.025% and brimonidine vehicle (placebo) for prevention of allergen-induced ocular redness. Subjects underwent screening, informed consent, and ocular assessment of baseline symptoms prior to allergen titration. Following titration, ocular and nasal allergy symptoms, measurement of IOP and diliated fundoscopy were evaluated. Following confirmation challenge (redness ≥ 2), subjects were randomized into 4 groups: BT 0.01%; BT 0.025%; OM 0.025%; and placebo. For allergen challenge, agents were instilled 15(± 5) minutes post-CAC; subjects were graded at 7, 15, and 20 minutes using a 0-4 redness scale. Secondary measures included ciliary and episcleral redness, itching, and tearing. Safety upon, and 1and 2 minutes post-instillation was graded using a 10 point scale.
Results:
Mean conjunctival redness scores in the BT 0.01% and BT 0.025% groups were significantly lower (P < 0.05) than placebo at all 3 post-CAC time points. Mean conjunctival redness scores in the OM 0.025% group were not significant versus placebo at any time point. Mean ciliary and episcleral redness scores in the BT 0.01% and the BT 0.025% groups were also significantly lower (P < 0.05) than the placebo group at all 3 time points. Treatment differences (active minus placebo) were greater than 0.5 units at all time points and greater than 1 unit for the majority of the time points measured for ciliary redness. Mean ciliary redness scores for both BT groups were significantly lower (P < 0.05) than the OM 0.025% group at 7 and 15 minutes post-CAC. Other secondary endpoints showed no significant difference between groups. Both BT solutions were found to be safe and well tolerated as dosed in this study.
Conclusions:
In this model of allergic redness, BT at both 0.01% and 0.025% demonstrated statistical superiority over placebo and OM in the prevention of conjunctival redness when CAC was performed 15 minutes post drug instillation.
Keywords: 421 anterior segment •
475 conjunctivitis •
479 cornea: clinical science