NR566 Week 2 Study Outline Chapter 17: Drugs Affecting the Respiratory System Bronchodilators: Beta 2 Receptor Agonists (B2RA): Short and long acting beta agonists • B2RA widely used in all ages to treat reversible bronc
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NR566 Week 2 Study Outline Chapter 17: Drugs Affecting the Respiratory System Bronchodilators: Beta 2 Receptor Agonists (B2RA): Short and long acting beta agonists • B2RA widely used in all ages to treat reversible bronchoconstriction caused by reactive airway disease (RAD) or COPD • Bronchodilators • Short-acting beta agonists: Albuterol (ProAir, Ventolin, Proventil) , metaproterenol (Alupent), terbutaline (Brethine, Brethaire), bitolterol (Tornalate), pirbuterol (Maxair), and levalbuterol (Xopenex) • Long-acting beta agonists: arformoterol (Brovana), salmeterol (Serevent), formoterol (Foradil), and indacaterol (Arcapta Neohaler) • Drug of choice during pregnancy for asthma Pharmacodynamics • Act on smooth muscle to reverse bronchospasm, decreases airway resistance and residual volume and increasing VC and airflow • Stimulate beta 2 adrenergic receptors in the lungs to increase cAMP production which relaxes bronchial smooth muscle and inhibits mediators from hypersensitivity cells (mast cells) • All beta agonists stimulate beta 1 activity (increased HR, tremor)f Short Acting Beta Agonists • Albuterol o Selective beta2 agonist with minor beta1 activity o Often first-line drug r/t less ADRs than the other drugs in this class o Increases HR by stimulating beta 2 receptors in the heart and vascular smooth muscle • Levalbuterol: (similar to albuterol), where the (S)-isomer from racemic albuterol is removed • Pirbuterol: selective beta 2 agonist, similar to albuterol • Terbutaline: similar to albuterol, selective beta 2 with minor beta 1 activity o Known to inhibit uterine contractions • Metaproterenol: beta 2 selective with some beta 1 activity, less selective than albuterol or terbutaline • Bitolterol: hydrolyzed by esterase in the lung to colterol, or terbutylnorepinephrine, selective beta 2
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