Bitolterol

**Semantic type:** Pharmacologic Substance

**Definition:** 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.

**Synonyms:** - BITOLTEROL