Absence of toxicity in patients with malignant otitis externa following long-term treatment with high dosage tobramycin.

An in-vitro model of aminoglycoside dosing was used to demonstrate that the bactericidal activity of tobramycin against Pseudomonas aeruginosa is directly related to the peak concentration of the drug. In addition, six patients who were being treated for malignant otitis externa with long-term, high dosage tobramycin were monitored for oto- and nephro-toxicity; the only adverse effects were transient increases in the serum creatinine concentration in two patients.