About montelukastleukotriene(cyslt1) receptor antagonist, antiinflammatory,antiasthma.mechanism of action of montelukastmontelukast is competitively and selectively antagonizes cyslt1 receptor (leukotrienes receptor) mediated bronchoconstriction.montelukast inhibits physiologic actions of ltd 4 at the cyslt1 receptor without any agonist activity. indications for montelukastasthma.interactions for montelukastbarbiturates & primidone: plasma concentration of montelukast is reduced by phenobarbital.