Inhibition by Amoxanox (AA-673) of the Immunologically, Leukotriene D4- or Platelet-Activating Factor-Stimulated Bronchoconstriction in Guinea Pigs and Rats

We studied the effects of amoxanox (AA-673) on allergic asthma and spasmogen-induced bronchoconstnction in guinea pigs and rats. Amoxanox given orally or parenterally inhibited allergic asthma mediated by IgE, IgG1, or heterologous IgG in guinea pigs and by IgE in rats. This compound also reduced leukotriene D4- and platelet-activating factor-induced bronchoconstnction in guinea pigs, strongly suggesting an antagonistic activity against slow reacting substance of anaphylaxis (SRS-A). Histamine- or acetylcholine-induced bronchoconstnction was not significantly affected by amoxanox. These antiasthmatic effects of amoxanox seem to be associated with an inhibition of the release of chemical mediators such as histamine and SRS-A and with an antagonism against SRS-A.