Penetration of ampicillin and sulbactam in the lower airways during respiratory infections.

We studied the penetration of ampicillin-sulbactam in the alveolar lining fluid (ALF) of eight patients after intravenous administration of 2,000 mg of ampicillin and 1,000 mg of sulbactam three times daily over 30 min. Bronchoalveolar lavage was performed on day 3, 30 min after the end of the morning drug administration. The mean penetration ratios (i.e., the ratios of the concentrations in ALF versus those in serum) were 53% (standard error, 12%) and 61% (standard error 31%) for ampicillin and sulbactam, respectively. The concentration ratio of ampicillin versus sulbactam in serum was not significantly different from that in ALF. From a pharmacokinetic point of view, ampicillin-sulbactam is a good choice for treatment of infectious exacerbation of chronic obstructive pulmonary disease and community-acquired bacterial pneumonia, since the concentrations of both drugs in ALF exceed the MICs for the respiratory pathogens responsible.