ANTIINFLAMMATORY ACTION OF METHIMAZOLE

The anti-inflammatory activity of 1-methylimidazole-2-thiol (methimazo le), the most widely used antithyroid drug, was investigated. Methimaz ole had a marked inhibitory action on prostaglandin H synthase (IC50 = 10 mu mol/l), inhibiting the peroxidase (IC50 = 330 mu mol/l), althou gh the cyclo-oxygenase was slightly activated. Methimazole was less po tent than indometacin (IC50 = 1.7 mu mol/l) on prostaglandin H synthas e, but was more potent than acetylsalicylic acid (IC50 = 160 mu mol/l) . Methimazole has been found to trap superoxide (O-2-(radical anion)) radicals and to decrease the level of blood prostaglandin E-2.