Name: Metaproterenol (Alupent)
Class: b2 Agonist
Mech.: b2 selective, but not as much as albuterol or terbutaline.
Absorption: Oral ® 40%. Inhalation of aerosol (onset in minutes).
Dist.:
Metab.:
Excretion, t½: Effects last 3-4 hrs.
Toxicity/S.E.s: Less likely w/inhalation. Tachycardia, arrhythmia, MI. risk w/underlying CV disease or use of MAO inhib. or tricyclics. Skeletal muscle tremor, restlessness, anxiety, apprehension. ¯ arterial O2 tension. High doses may cause myocard. necrosis, ¯ plasma K+, plasma glucose. hyperglycemia in diabetics, ¯ K+ in cardiac patients (esp. those taking cardiac glycosides and diuretics).
Utility: Treat asthma.
Special Features: b2s are DOCs for sympathomimetic treatment of asthma.