PULMONARY CONCENTRATIONS OF DIRITHROMYCIN AND ERYTHROMYCIN DURING ACUTE EXACERBATION OF MILD CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

We compared the concentrations of dirithromycin and erythromycin at st eady state in serum and the intrapulmonary region in patients sufferin g from acute exacerbation of mild chronic obstructive pulmonary diseas e. Twenty patients received dirithromycin, 500 mg given orally once da ily for five consecutive days. The other 20 patients were treated with erthromycin base, which was administered orally four times daily at a total daily dose of 1000 mg for seven days, All patients were divided into eight groups, with five subjects in each group, according to sam pling times (2, 4, 8, and 24 hrs after the last dose) and treatment. A fter the erthromycin treatment mean serum concentrations were higher t han those of dirithromycin treatment mean serum concentrations were hi gher than those of dirithromycin for up to 4 hours, but they were unde tectable 24 hours after the last dose. At all time periods, the concen trations of dirithromycin in bronchial secretion, bronchial mucosa and epithelial lining fluid were greater than the concentration in serum. Concentrations of erythromycin were always lower than those of dirith romycin in the explored pulmonary sites. Our data demonstrated that a five day course of 500 mg of dirithromycin once daily induced higher c oncentrations and longer persistence in the various potential sites of pulmonary infection than a seven day course of 250 mg of erythromycin every 6 hrs. The shorter duration of therapy and the once daily dosin g with good efficacy against common respiratory pathogens would be adv antageous for patients and would be likely to promote better patient c ompliance and acceptability. (C)ERS Journals Ltd 1997.