Nadolol for Treatment of Supraventricular Tachycardia in Infants and Young Children.

Supraventricular tachycardia (SVT) is a common infant arrhythmia, for which beta-blockers are frequently chosen as therapy. Propranolol is a common choice though it is dosed every 6-8 h. We reviewed the clinical results of treating infant SVT with an extemporaneous preparation of nadolol. Retrospective cohort study of patients under 2 years old receiving nadolol for SVT at a single center. Patients were ascertained by patient and pharmacy databases. Twenty-eight infants received nadolol, of whom 25 had regular narrow complex tachycardia, 2 atrial flutter, and 1 focal atrial tachycardia. Patient age at initiation was a median 54 days (range 10-720). The final dose was 1 mg/kg/day in 22/28 patients (range 0.5-2). Once-daily dosing was used in 20 patients (71.4%); dosing was BID in 7, TID in 1. Among regular narrow complex tachycardia patients, 18/25 received nadolol monotherapy and 7 required additional agents; flecainide in 6, digoxin in 1. The median age of tachyarrhythmia onset was 18 days (range 1-180) with a median age of nadolol initiation of 30 days (range 11-390). Of the 20 regular narrow complex tachycardia patients initiated on nadolol monotherapy, 85% had no recurrences as of 1-year follow-up. Side effects were suspected in 3 of 28 (10.7%), including wheezing (n = 1, 3.5%), irritability and diarrhea (n = 1, 3.5%), and bradycardia (n = 1, 3.5%). Oral nadolol suspension was a successful treatment for SVT in 85% of patients with minimal adverse effects. Single daily dosing was used in the majority of patients.