Impact of infusion method on amikacin serum levels in humans.

Aminoglycosides are broad-spectrum antibiotics with peak-dependent bactericidal activity, administered by gravity infusion or for more accuracy by electronic pump infusion. The aim of this study was to assess the difference between the two systems and its pharmacokinetic impact. Twenty-four patients hospitalised for community-acquired pulmonary infections received amikacin by IV route over 1 h with a targeted peak concentration of 35 mg/L. They were randomly distributed into two groups, one receiving infusion through a pump system, the other by gravity. Amikacin serum levels were determined at the end of infusion and 24 h later. C(max) values were significantly lower with gravity than pump (40.2 +/- 12.3 vs. 50.6 +/- 17.6 mg/L, respectively; p = 0.04). Elimination half-life time, volume of distribution and clearance did not differ significantly from one group to the other. The percentage of patients who failed to achieve the targeted peak concentration was significantly higher with gravity than pump (41.7% vs. 16.7%, respectively; p < 0.001). Improving infusion flow-rate provides better control over amikacin C(max). This study underlines the fact that infusion device characteristics should be added to the physiopathological information of a patient if we are to make a better estimation of pharmacokinetic parameters.