NCIt definition : The potassium salt form of pemirolast, a pyrimidinone derivative with antiallergic
property. Pemirolast potassium exerts its action by blocking the antigen-mediated
calcium ion influx into mast cells. This prevents mast cell degranulation, resulting
in mast cell stabilization and inhibition of the release of inflammatory mediators,
histamine and leukotrienes, which are involved in the allergic process. Pemirolast
potassium also prevents inflammatory mediator release from eosinophils.;