Efficacy and pharmacokinetics of arbekacin administered by inhalation to patients with lower respiratory tract MRSA infections

Abstract

We treated 5 patients with respiratory tract MRSA infections with arbekacin administered by inhalation of 100mg to investigate its clinical efficacy, serum levels and pharmacokinetics. The results were as follows:
1) The serum level of the drug reached the maximum concentration of 0.366μg/ml in 1 patient 3h after inhalation, but was below the detection limit in 4 other patients.
2) The maximum daily urinary excretion was 2.33 mg, suggesting that the in vivo absorption rate would be 3.9% as the maximum, taking into consideration the fact that the urinary recovery rate was about 60% after the intravenous administration.
3) Bacteria disappeared in 2 patients and decreased in one after inhalation of arbekacin.
4) One patient complained of slight pharyngeal discomfort 4 days after the initiation of treatment, but therapy was continued and the symptom disappeared rapidly after treatment was finished.
5) Inhalation of arbekacin at a daily dose of 100mg was therefore thought to be effective in patients who do not respond to systemic antimicrobial therapy.