title: The pharmacokinetics of isoproterenol in critically ill pediatric patients.
abstract: The pharmacokinetics of isoproterenol (ISO) in infants and children have never been reported. The authors studied ISO pharmacokinetics in two disparate groups of pediatric intensive care unit patients: postoperative cardiac patients (POC, n = 10), and reactive airway disease patients (RAD, n = 9). In all, 44 blood samples were taken at steady-state from the 19 patients, whereas from 15 patients samples were also taken just before and after discontinuation of ISO infusion. There were 12 male and 7 female patients in the study, and their ages ranged from 2 days to 14 years. The average ISO dosing rate was 0.30 micrograms/kg/minute for the whole study population, ranging from 0.01 to 5.5 micrograms/kg/minute. The POC patients received a significantly lower dosing rate than the RAD patients (0.029 +/- 0.002 vs 0.50 +/- 0.21 micrograms/kg/minute, P < .0001); the average steady-state plasma concentrations of ISO were also lower in the POC patients (1.3 +/- 0.3 versus 13.9 +/- 4.9 ng/mL, P < .0001). The steady-state plasma concentration, normalized to a dosing rate of .05 micrograms/kg/minute, was 1.9 +/- 0.3 ng/mL for all patients, and the clearance was 42.5 +/- 5.0 mg/kg/minute. Postoperative cardiac patients had a significant higher normalized steady-state plasma concentration and moderately significant lower clearance than did RAD patients (2.1 +/- 0.3 versus 1.7 +/- 0.4 ng/mL, P < .05 and 33.2 +/- 4.9 versus 48.4 +/- 7.3, P < .06, respectively). The average plasma half-life of ISO was 4.2 +/- 1.5 minutes, and the volume of distribution was 216 +/- 57 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Pediatric ICU Research Laboratory, Childrens Hospital Los Angeles, University of Southern California School of Medicine 90027.
authors.forename: G
authors.initials: G
authors.lastname: Reyes
authors.forename: P H
authors.initials: PH
authors.lastname: Schwartz
authors.forename: C J
authors.initials: CJ
authors.lastname: Newth
authors.forename: M K
authors.initials: MK
authors.lastname: Eldadah
mesh_terms: D000293:Adolescent; D001145:Arrhythmias, Cardiac / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D016638:Critical Illness; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric; D007545:Isoproterenol / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male; D011183:Postoperative Complications / Q000378:metabolism*; D012140:Respiratory Tract Diseases / Q000378:metabolism*
chemical_list: D007545:Isoproterenol