BRONCHOSTIM 12MCG/DOSE AEROSOL

MECHANISM OF ACTION THE PHARMACOLOGIC EFFECTS OF BETA2-ADRENOCEPTOR AGONIST DRUGS INCLUDING FORMOTEROL ARE AT LEAST IN PART ATTRIBUTABLE TO STIMULATION OF INTRACELLULAR ADENYL CYCLASE THE ENZYME THAT CATALYZES THE CONVERSION OF ADENOSINE TRIPHOSPHATE (ATP) TO CYCLIC-3 5 -ADENOSINE MONOPHOSPHATE (CYCLIC AMP). INCREASED CYCLIC AMP LEVELS CAUSE RELAXATION OF BRONCHIAL SMOOTH MUSCLE AND INHIBITS THE RELEASE OF PRO-INFLAMMATORY MAST-CELL MEDIATORS SUCH AS HISTAMINE AND LEUKOTRIENES. FORMOTEROL ALSO INHIBITS HISTAMINE-INDUCED PLASMA ALBUMIN EXTRAVASATION IN ANESTHETIZED GUINEA PIGS AND INHIBITS ALLERGEN-INDUCED EOSINOPHIL INFLUX IN DOGS WITH AIRWAY HYPER-RESPONSIVENESS. THE RELEVANCE OF THESE IN VITRO AND ANIMAL FINDINGS TO HUMANS IS UNKNOWN.