Pharmacodynamics and toxicology of fenflumizole, a new non-steroidal anti-inflammatory imidazole derivative.

Fenflumizole, (2-(2,4-difluorophenyl)-4,5-bis(4-methoxyphenyl) imidazole), a new non-steroidal anti-inflammatory agent, was investigated for anti-inflammatory, analgesic and anti-pyretic activity in experimental animals. Comparison was made to other non-steroidal anti-phlogistics. Furthermore, general pharmacodynamics and toxicity of fenflumizole was studied. Fenflumizole was comparable to or weaker than indomethacin in models of acute inflammation (carrageenin paw oedema and pleurisy, rats, ultraviolet erythema, guinea-pigs) and stronger than indomethacin as an analgesic (writhing, mice). As an antipyretic agent (arachidonic acid pyresis, rats) fenflumizole was 3 times weaker than indomethacin. The acute gastro-ulcerogenicity and toxicity of fenflumizole was low as compared to reference drugs. No untoward activity of fenflumizole on respiratory and circulatory systems was observed in rabbits and dogs. Fenflumizole is a potential new therapeutic agent with anti-inflammatory, analgesic and anti-pyretic activities comparable to other anti-phlogistics but with reduced side effects.