Efficacy of a three day course of azithromycin in moderately severe community-acquired pneumonia.

This study was designed to evaluate the efficacy of a 3 day course of azithromycin in low to moderately severe community-acquired pneumonia. Forty patients with low to moderately severe community-acquired pneumonia (29 males, 11 females, mean age 46 +/- 17 yrs; 20 pretreated with betalactams for 2-10 days with no results before admission to hospital; 18 with evidence of co-morbidity) were enrolled in an open, randomized study with azithromycin, 500 mg q.d. oral therapy for 3 days, versus clarithromycin, 250 mg b.i.d. oral therapy for 10 +/- 2 days. The aetiology of pneumonia was identified in 18 patients by serology (nine Mycoplasma pneumoniae, four Chlamydia pneumoniae, five Legionella pneumophila; one patient with chlamydial infection also had Klebsiella pneumoniae bacteraemia). A presumptive aetiological diagnosis was obtained with sputum culture in three other patients (one Haemophilus influenzae, two Haemophilus parainfluenzae), all strains were sole isolates with 10(8) Colony forming units (CFU), and with Gram stain in one patient with Streptococcus pneumoniae. All patients in the azithromycin group (one after a second 3 day course), and all but two (of those available for evaluation) of the clarithromycin group were cured. Defervescence occurred after 2.6 +/- 1.6 days, and chest roentgenogram cleared after 8.9 +/- 3.3 days, with no difference between the two groups. Tolerance was good, and there were no withdrawals from therapy.(ABSTRACT TRUNCATED AT 250 WORDS)