Isoproterenol
Pharmacology. Isoproterenol is a catecholamine-like drug that stimulates beta-adrenergic receptors (beta1 and beta2). Its pharmacologic properties include positive inotropic and chronotropic cardiac effects, peripheral vasodilation, and bronchodilation. Isoproterenol is not absorbed orally and shows variable and erratic absorption from sublingual and rectal sites. The effects of the drug are terminated rapidly by tissue uptake and metabolism; effects persist only a few minutes after intravenous injection.
Indications
Severe bradycardia or conduction block resulting in hemodynamically significant hypotension (See Hypotension). Note: After beta blocker overdose, even exceedingly high doses of isoproterenol may not overcome the pharmacologic blockade of beta receptors, and glucagon (See Glucagon) is the preferred agent.
To increase heart rate and thereby abolish polymorphous ventricular tachycardia (torsade de pointes) associated with QT-interval prolongation (See Ventricular dysrhythmias).
To relieve bronchospasm (although beta2-selective drugs such as albuterol are preferred).
Contraindications
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