UMEM Educational Pearls

Category: Cardiology

Title: isoproterenol

Keywords: isoproterenol, bradycardia, torsades de pointes (PubMed Search)

Posted: 12/26/2010 by Amal Mattu, MD
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Isoproterenol is a non-selective beta-1 and beta-2 agonist. The beta-1 effect produces an increase in heart rate, and the beta-2 effect produces mild vasodilation. Two times to consider its use are the following:
1. For overdriving pacing in cases of intermittent torsades de pointes when magnesium is ineffective.
2. For intractable bradycardia, this is another option besides dopamine or epinephrine. Because of the vasodilation, isoproterenol might be preferred to these other drugs when the bradycardia is accompanied by severe hypertension or when vasoconstrictors are not desired.

The drug is not commonly used anymore but is effective in treating persistent bradycardia or for overdrive pacing in patients with intermittent torsades de pointes when magnesium is ineffective. Be wary, though, that the beta-2 effect produces vasodilation so there may be a mild reduction in blood pressure when the drug is used.