ALBUTEROL SULFATE

12.1 Mechanism of Action In vitro studies and in vivo pharmacologic studies have demonstrated that albuterol has a preferential effect on beta 2 -adrenergic receptors compared with isoproterenol. Although beta 2 -adrenoceptors are the predominant adrenergic receptors in bronchial smooth muscle and beta 1 -adrenoceptors are the predominant receptors in the heart, there are also beta 2 -adrenoceptors in the human heart comprising 10% to 50% of the total beta-adrenoceptors. The precise function of these receptors has not been established, but their presence raises the possibility that even selective beta 2 -agonists may have cardiac effects. Activation of beta 2 -adrenergic receptors on airway smooth muscle leads to the activation of adenyl cyclase and to an increase in the intracellular concentration of cyclic-3′,5′-adenosine monophosphate (cyclic AMP). This increase of cyclic AMP leads to the activation of protein kinase A, which inhibits the phosphorylation of myosin and lowers intrace

Contraindications

• • 4 CONTRAINDICATIONS Albuterol Sulfate HFA is contraindicated in patients with a history of hypersensitivity to any of the ingredients [see Warnings and Precautions ( 5.6 )
• • Description ( 11 )] . Hypersensitivity to any ingredient. ( 4 )