NCIt definition : The mesylate salt of bitolterol, a diester sympathomimetic amine with bronchodilator
activity. As an ester prodrug, bitolterol is hydrolyzed by esterases to its active
metabolite colterol (N-t-butylarterenol). Colterol selectively binds to and activates
beta-2 adrenergic receptors in bronchiolar smooth muscle, thereby causing stimulation
of adenyl cyclase, the enzyme that catalyzes the conversion of adenosine triphosphate
(ATP) to cyclic-3',5'-adenosine monophosphate (cAMP). Increased intracellular cAMP
levels cause relaxation of bronchial smooth muscle. This increases air flow and prevents
bronchospasms and may eventually lead to an improvement of airway function.;