INTERACTION OF DEXAMETHASONE WITH ACETYLSALICYLIC-ACID IN MICE

The effect of acetylsalicylic acid (ASA, 160 mg/kg b.wt.) and dexameth asone (DEX, 15 mg/kg b.wt.) on ASA antinociception and toxicity when a dministered orally alone or in combination for 4 consecutive days was studied in male albino mice. ASA antinociception decreased after repea ted ASA administration. Bleeding time was prolonged and the intestinal ASA esterase activity was increased, which was probably related to th e increased ASA general toxicity in ASA-treated animals. There were no changes in the blood alkaline content, in the ulcerogenic or hepatoto xic effect of ASA, nor in the hepatic monooxygenase activity (ethylmor phine N-demethylase and aniline hydroxylase and the cytochrome P450 an d b-5 content). DEX administered alone exerted a significant antinocic eptive effect, increased both acute ASA toxicity and aniline hydroxyla se activity and decreased body growth. However DEX did not change the bleeding time, the alkaline blood content nor the intestinal esterase activity. The combination of ASA and DEX did not increase the ASA anti nociceptive effect nor the general and specific toxicity of ASA. DEX i n combination even abolished the effect of ASA on intestinal ASA ester ase and on bleeding time. DEX also increased the hepatic cytochrome P4 50 content and did not change the ulcerogenic effect of ASA nor the al kaline blood content.