Peak or sustained antibiotic serum levels for optimal tissue penetration.

A comparative study of the levels of netilmicin in bronchial secretions after intermittent and during continuous intravenous injections was performed. During the first 2 h, the areas under the drug concentration curves in the bolus injection experiment were greater in serum and in bronchial secretions (206 and 150% respectively) than those associated with the continuous infusion (P<0.001); however, during the 8 h experimental period, the areas under the curves were similar in serum and bronchial secretions with the two modes of administration. The percentages of penetration of netilmicin from the blood to the bronchial lumen were also similar with the two modes of administration (19%). After intramuscular administration of amikacin (7.5 and 12.5 mg/kg twice daily), the peak bronchial secretion levels of the drug were 4.4 and 10.1 mg/l respectively and the trough levels about 1 mg/l. During continuous iv injection of amikacin (7–12 mg/kg/8 h), the drug level in the bronchial secretions was only 2.0 mg/l and the percentage of penetration was 14.9% adequate anti-Pseudomonas activity in bronchial secretions was rarely achieved. It is therefore suggested that intermittent injections of aminoglycosides can result in at least transitory higher bronchial secretion levels than continuous injection: the intermittent schedule of antibiotic administration could therefore be recommended in the treatment of bronchopulmonary infections since it has been suggested that the concentration of antibiotic in bronchial secretions could be important in the outcome of these infections. [ABSTRACT FROM PUBLISHER]