Apraclonidine 0.5% Versus Brimonidine 0.2% for the Control of Intraocular Pressure Elevation Following Anterior Segment Laser Procedures

Abstract

Both apraclonidine hydrochloride 0.5% and brimonidine tartrate 0.5% are potent alpha-2 agonists, effective in controlling the intraocular pressure (IOP) rise following argon laser trabeculoplasty (ALT). Brimonidine has recently become available commercially as a 0.2% solution. Our goal in this study was to compare the efficacy and side effect profile of 0.2% brimonidine to that of 0.5% apraclonidine in the prevention of IOP spikes following anterior segment laser procedures. Patients undergoing argon laser trabeculoplasty, Nd:Yag peripheral iridectomy or posterior capsulotomy were prospectively randomized to receive either apraclonidine 0.5% or brimonidine 0.2%, approximately 10 minutes prior to laser surgery. Intraocular pressure was measured by a masked observer, using Goldmann applanation tonometry, before and 1 hour after the treatment. 51 ALTs, 21 peripheral iridectomies, and 13 posterior capsulotomies were performed. The incidence of an IOP rise greater than 5 mmHg was 3/43 (7.0%) in the brimonidine group and 0/42 (0%) in the apraclonidine group (P = 0.08, chi-squared). There were no IOP elevations greater than 8 mmHg. All IOP rises of greater than 5 mmHg occurred in the ALT sub-group, and within this sub-group, the mean change in IOP from pre- to post-op was -4.00 +/- 5.87 in the brimonidine group versus -4.29 +/- 3.86 in the apraclonidine group (P = 0.84). There was a statistically significant decrease in IOP from baseline in both drug groups (P < .0001). Both drugs are highly effective in controlling IOP spikes following anterior segment laser procedures. There is a tendency toward higher risk of IOP rise following argon laser trabeculoplasty with 0.2% brimonidine as compared to 0.5% apraclonidine, however, this was not statistically significant.