Aims: We investigated the effect of several Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), on the preoptic nerve oxygen tension (ONPO 2 ), as indomethacin previously has demonstrated a strong decreasing effect on ONPO 2 . We tested whether these NSAIDs, like indomethacin, also reduce the increasing effect of dorzolamide on ONPO 2 . Methods: ONPO 2 was measured 0.5 mm above the optic disc in 23 domestic pigs (26-36 kg) with a polarographic oxygen-sensitive electrode. One of the following NSAIDs

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... was administered intravenously as increasing doses or as one large dose: indomethacin, ibuprofen, diclofenac, ketoprofen, parecyclo-oxygenase-2 inhibitor and lornoxicam. Indomethacin was both tested alone and after preceding administration of the other NSAIDs. Dorzolamide was also tested after preceding administration of NSAIDs different from indomethacin. Results: Indomethacin decreased ONPO 2 significantly in a dose-dependent manner. None of the other NSAIDs produced any effect on the ONPO 2 (p..0.05; n = 17). No difference was found between the effect of indomethacin injected alone, and after preceding administration of the other NSAIDs. Intravenous dorzolamide (500 mg) increased ONPO 2 by 32 (7)% (n = 7; p,0.001) after preceding administration of several NSAIDs different from indomethacin. Conclusions: Indomethacin decreased ONPO 2 , while the other NSAIDs showed no effect on ONPO 2 , and they did not affect the effect of indomethacin. The hypoxic effect of indomethacin must be due to another mechanism than cyclo-oxygenase inhibition. The effect of dorzolamide on ONPO 2 is not related to prostaglandin production. 126 BNF for Children 2006, second annual edition In a single resource: c guidance on drug management of common childhood conditions c hands-on information on prescribing, monitoring and administering medicines to children c comprehensive guidance covering neonates to adolescents For more information please go to bnfc.org.