Pediatric Dosing of Intravenous Sotalol Based on Body Surface Area in Patients with Arrhythmia

In a recently published study, we evaluated the efficacy and safety of intravenous sotalol in pediatric patients with incessant tachyarrhythmias and we have found that intravenous sotalol is effective and safe. Our dosing regimen was based on the body weight of the patients. In the US, the recommendation for intravenous sotalol dosing in pediatric patients is based on body surface area (BSA) while taking into consideration the patients' age. The purpose of this paper is to show the correspondence of a body weight-based dosing regimen when expressed for BSA as mg/m². We evaluated the similarity of a body weight-based dose to that calculated based on BSA using the US labeling recommendations. Of the 83 patients, 5 were newborns (age: 0-30 days), 39 infants and toddlers (age: 1-24 month), 26 young children (age: >2-6 years), 11 older children (age: 6-12 years), and 2 adolescents (age: 14 years). Each received a loading dose of 1 mg/kg intravenous sotalol administered over 10 min followed by a maintenance dose of 4.5 mg/kg/day. There was a close correlation between the sotalol loading doses calculated based on body weight and BSA across the entire age range (r = 0.977, p < 0.001). In most of the age groups, the body weight-based loading doses were lower or equal to the BSA-based doses. Only in the adolescents were the body weight-based doses higher. The maintenance doses given in our study were significantly higher than the BSA-based dose in newborns: 75 ± 6 versus 53 ± 8 mg/m², p < 0.05; infants/toddlers: 88 ± 14 versus 77 ± 7 mg/m², p < 0.001; younger children: 113 ± 12 versus 85 mg/m², p < 0.001; older children: 123 ± 16 versus 85 mg/m², p < 0.01; and adolescents 157 ± 30 versus 85.5 mg/m². Despite the rapid administration of the loading dose and the increased maintenance doses, our body weight-based dosing regimen was safe. Only one newborn had significant adverse event (AV block) that resolved spontaneously after discontinuation of the infusion.