Nicardipine inhibits acute rise of aqueous flare and intraocular pressure induced by argon laser photocoagulation

The purpose of this study was to examine the anti-inflammatory effect of the calcium channel blocker nicardipine. Intraocular inflammation was induced by argon laser photocoagulation of the iris of pigmented rabbits and was assessed by measuring aqueous flare and intraocular pressure. This resulted in a marked increase in the aqueous flare that peaked at approximately one hour following coagulation and returning to the original values after six hours. Intraocular pressure increased within 15 minutes following laser treatment and returned to baseline levels at 60 minutes. Pre-treatment of the rabbits with an intravenous injection of 2 mg/kg of nicardipine completely abolished both the increase in aqueous flare and intraocular pressure induced by laser photocoagulation as compared to the control experiment. Earlier work from the author's group has shown that nicardipine can also block aqueous flare and intraocular pressure increases induced by topical administration of prostaglandin E2. From these combined experiments they would like to draw the conclusion that the inflammatory reaction induced by photocoagulation of the iris is partly mediated by prostaglandins and that blockade of calcium channels by nicardipine can inhibit the effects induced by prostaglandin E2.