This retrospective study involved a cohort of 197 patients representing 213 admissions to the CCU over a 6-month period. The median initial loading dose was 99.2 Hg/kg, and the median infusion rate was 0.64 Hg/kg per minute for a median duration of 43.1 hours. Milrinone duration was significantly associated with low cardiac output syndrome, but milrinone dosing was not significantly associated with adverse effects (arrhythmia or thrombocytopenia).
Dosing of Milrinone
For most of the admissions (92%), the patients received a loading dose, usually (for 80.3% of admissions) before admission to the CCU (i.e., in the operating room). There was no apparent tapering of dose in two-thirds of the patients. Three major findings were observed regarding milrinone dosing. cialis super active
First, initial loading doses (median 99.2 Hg/kg) exceeded the dose recommended in the literature (50 Hg/kg), but infusion rates were within ranges studied in children (0.2 to
0.75 Hg/kg per minute) and adults (0.375 to 0.75 Hg/kg per minute). Among the 196 admissions in which the patient received one or more loading doses, the initial loading dose was greater than 80 Hg/kg for 134 (68.4%); this value is almost twice the recommended loading dose for adults (50 Hg/kg). The data from pediatric studies are conflicting, with loading doses ranging from 50 to 135 Hg/kg. In the current study, initial loading doses were higher if given in the operating room. For adults with cardiopulmonary bypass, loading doses above the usual 50 Hg/kg were needed to achieve therapeutic milri- none concentrations. Loading doses of 100 Hg/kg and greater have been studied in neonates with cardiopulmonary bypass.
Second, repeat loading doses (median 49 Hg/kg) were common, which again raises the question of whether an optimal maintenance dosing regimen was being used. Taken with the high incidence of low cardiac output syndrome among patients who were receiving milrinone, these data suggest that dosing recommendations may require further evaluation.
Third, the milrinone dose was not adjusted for patients with renal impairment. The correlation between average dose rate and creatinine level was weak (r2 < 0.1 for all pediatric age groups; Figure 2). This is relevant because up to 85% of milrinone is eliminated renally, and for 34.9% of the admissions, the patient had a high creatinine level relative to age-defined normal ranges. The manufacturer recommends adjustment of the milrinone dosage for adults with severe renal impairment,20 and milrinone has a longer serum half-life andlower renal clearance in patients with renal impairment than in healthy patients. To date, no prospective studies have described the optimal dose adjustment for children with renal impairment. canada pharmacy mall