Otolaryngologists using local anesthetics containing epinephrine.

Abstract

To the Editor .—In a recent commentary, Brummett 1 drew attention to a common, yet potentially life-threatening, drug interaction between nonselective β-adrenergic blockers and epinephrine. However, there were some serious typographical errors in his article and misleading recommendations as to the appropriate clinical response. First, β 1 and β 2 have been transposed throughout the commentary. The β 1 -receptors, not the β 2 , are those found in the heart, which, when stimulated, increase heart rate and contractility. 2 Epinephrine activates both α- and β 2 -receptors in blood vessels to mediate the opposing effects of vasoconstriction (α) and vasodilation (β 2 ). The net effect of low doses of epinephrine in healthy patients is only an increase in heart rate because of β 1 stimulation. 3 Higher doses of epinephrine produce systolic hypertension as well as tachycardia. 3 If the β 1 - and β 2 -receptors are blocked by a