Pharmacokinetics of Catecholamines During Hemofiltration in Pediatric Patients

BACKGROUND: Continuous hemofiltration is used in pediatric patients with acute renal failure. Many of these patients are treated with catecholamines for hemodynamic instability. The authors studied the pharmacokinetics of dopamine and dobutamine on patients undergoing continuous venovenous hemofiltration. METHODS AND RESULTS: Three critically ill pediatric patients with acute renal failure and cardiovascular instability treated with hemofiltration and intravenous infusion of dopamine and/or dobutamine were entered into the study. Blood samples were drawn at steady-state levels from the arterial port (inflow) of the hemofilter, from the venous port (outflow) of the hemofilter, and from the ultrafilter. Sixteen (n = 16) pharmacokinetic measurements were made, six (n = 6) for dopamine and 10 (n = 10) for dobutamine. The clearance of dopamine by the hemofilter was 0.078 +/- 0.011 mL/kg/min, and for dobutamine it was 0.036 +/- 0.008 mL/kg/min. On the average, 0.56% of the dopamine dose and 0.13% of the dobutamine dose was removed by the hemofilter. CONCLUSIONS: The pharmacokinetics of dopamine and dobutamine at the dosage range of 5-25 µg/kg/min are not altered by continuous hemofiltration. Relative to total plasma clearance, negligible amounts of the drug were removed. The dosage of these catecholamines need not be adjusted during continuous hemofiltration.