Endosprin, an antipyretic, antiinflammatory and analgesic preparation of lysine salicylate: reassessment of its chemical composition and effects in experimental animals in comparison with aspirin.

Endosprin, an antiinflammatory-antipyretic-analgesic salicylate drug marketed in Brazil since 1970, has been shown by NMR-1H spectral analysis to contain salicylic acid and not, as formerly believed, acetylsalicylic acid (aspirin). Its analgesic and antiinflammatory activity in mice and rats was similar to that of aspirin but its antipyretic activity against bacterial pyrogen fever in rabbits was significantly lower than that of aspirin. This result stands in contrast to the large body of clinical evidence indicating a rather high degree of effectiveness of Endosprin in lowering fever of various origin in children.