Rapid intravenous injection of tobramycin: suggested dosage schedule and concentrations in serum

A single, rapid intravenous injection of tobramycin in doses of 1.5 mg/kg or 80 mg administered to subjects with normal renal function produced a wide range of concentrations in serum. Serum concentrations peaked at greater than 20mug/ml in one third of the subjects, but these peaks were transitory. At 6 hr the serum levels were less than 2 mug/ml in all but one subject and were less than 0.1 mug/ml in 50% of the subjects. A dosage interval of 6 hr with a total dosage of 6 mg/kg per day is recommended. The variation in individual dose responses emphasizes the need for monitoring of levels of tobramycin in serum during treatment. Serum concentrations of 4-6 mug/ml 1 hr after injection can be considered indicative of adequate therapy. Levels in serum 6 hr after administration should also be monitored, particularly in the elderly. No immediate or delayed toxic effects were observed after intravenous injection of tobramycin.