Mechanism of action of colchicine. III. Antiinflammatory effects of colchicine compared with phenylbutazone and indomethacin.

Colchicine suppresses the development of carrageenan-induced edema in the rat with a minimum effective oral dose of 6.0 mg/kg. The slope of the dose-response regression line for colchicine differs significantly from that of indomethacin and phenylbutazone. Based on the dosages required to achieve a 50% suppression of this inflammation, colchicine is 0.6 and 1.5 times as potent as indomethacin and phenylbutazone, respectively. In the reversed passive Arthus reaction in the rat, the suppressive activity of colchicine is at least 50 times that of indomethacin and 100 times that of phenylbutazone. The possible significance of these results with regard to the unique effectiveness of colchicine in the treatment of gout is discussed.