Arachidonic acid-induced elevation of intraocular pressure and anti-inflammatory agents.

Arachidonic acid, a precursor of prostaglandin E2 subconjunctivally injected into rabbit eyes in concentrations of 0.8 to 5 per cent, produced a dose-related rise of intraocular pressure (IOP) similar to the one observed after topical administration of PGE2 in concentrations of 0.001 to 0.1 per cent. Indomethacin, a nonsteroidal anti-inflammatory agent, had an inhibitory effect when administered systemically or topically prior to arachidonic acid. Dose-response relationships were demonstrated by topical and oral administration of Indomethacin which, as expected, had no effect on PGE2. Dexamethasone did not exert any inhibitory effect on the increased IOP following arachidonic acid administration. Indomethacin applied topically readily penetrated into the aqueous humor in concentrations considerably above those appearing in the plasma, which justifies the use of this route of administration. Since prostaglandin (PG) appeared to be implicated in ocular inflammation, these findings underline the specificity of action of Indomethacin and suggest its use in the topical treatment of ocular inflammation.