Effect of U74006F (Tirilazad Mesylate) in rabbit eyes after argon laser trabeculoplasty

A new free radical scavenger, U74006F (Upjohn Company, Kalamazoo, MI, USA) was studied to determine if it would have a beneficial effect on preventing intraocular pressure (IOP) spikes and reducing blood-aqueous barrier (BAB) breakdown in rabbits after argon laser trabeculoplasty (ALT). The post-ALT IOP averaged 24.7 mm Hg (+/- 3.8 mm Hg; N = 6) and 30.3 mm Hg (+/- 6.9 mm Hg; N = 7) at 1 hour (p = 0.097) and 22.7 mm Hg (+/- 1.9) and 27.3 mm Hg (+/- 7.0 mm Hg) at 3 hours in the U74006F and vehicle groups (p = 0.137), respectively. By 48 hours, the IOP averaged 12.8 +/- 2.2 mm Hg in the U74006F group and 12.4 +/- 2.4 mm Hg in the vehicle group (P = 0.757). The aqueous fluorescein permeability (AFP) between lasered and unlasered eyes was determined for the U74006F and vehicle-treated groups by aqueous fluorophotometry. Prelaser or baseline AFP was determined for the U74006F (-0.236 +/- 0.236) and vehicle (-0.145 +/- 0.237) groups (p = 0.505). At day 2 posttreatment, the U74006F group and the placebo group both reported similar AFP of 5.109 +/- 4.831 and 5.680 +/- 4.280 (p = 0.827), respectively. At one week post-ALT, AFP for the U74006F group (0.109 +/- 0.367) had returned close to baseline, while that of the vehicle group (0.426 +/- 0.511) was still quite elevated (p = 0.220). U74006F appears to be beneficial in the prevention of acute elevation of IOP following ALT but not in the prevention of Blood-Aqueous Barrier (BAB) breakdown.