Aqueous prostaglandin E2 and intraocular pressure after argon laser trabeculoplasty in glaucoma patients pretreated with topical piroxicam.

Intracameral injection of prostaglandin E2 causes an increase in intraocular pressure (IOP) in rabbits, cats, and monkeys. Arachidonic acid administered topically in rabbits and monkeys also increases IOP. The effect of prostaglandin E2 on IOP in human eyes is unclear. We performed paracentesis of the anterior chamber one hour after 180 degrees argon laser trabeculoplasty in cases of primary open-angle glaucoma. This laser treatment may increase IOP, but no correlation was found between post-operative IOP changes and PGE2 levels. PGE2 was significantly lower in ten eyes pretreated with topical piroxicam, a prostaglandin biosynthesis inhibitor (7 +/- 6 pg/ml), than in ten untreated eyes (443 +/- 232 pg/ml) and five controls. No significant difference was found between post-operative IOP in eyes pretreated and untreated with piroxicam. The low levels of PGE2 in the aqueous humour of eyes pretreated with piroxicam indirectly demonstrated the transcorneal penetration of the topically-administered drug, and the effectiveness of piroxicam in inhibiting the ocular synthesis of PGE2.