Analgesic and anti-inflammatory activity of 6-chloro-alpha-methyl-carbazole-2-acetic acid (C-5720).

The carbazole, C-5720, has the same order of analgesic, antipyretic and anti-inflammatory activity as indomethacin and is more potent than phenylbutazone and acetylsalicylic acid in the yeast inflamed paw, the carrageenin foot edema, the Mycobacterium butyricum-induced pyrexia, and the acute and chronic adjuvant arthritis tests. In chronic adjuvant arthritis in rats, C-5720 lowers the elevated serum mucopolysaccharide and plasma fibrinogen levels, and partially restores the depressed liver N-demethylase activity. C-5720 is 16 times less active than indomethacin in the production of gastric ulcers in rats and is about 70 times less active than indomethacin in blocking arachidonic acid-induced diarrhea in mice. C-5720 has a greater safety margin than indomethacin with respect to the production of gastric ulcers or the blockade of diarrhea and the reduction of inflammation in adjuvant-induced polyarthritis.