A comparison of 5-day courses of dirithromycin and azithromycin in the treatment of acute exacerbations of chronic obstructive pulmonary disease.
BACKGROUND
Short-term use of antibiotics has become a common component of the management of acute exacerbations of chronic bronchitis (AECB), particularly in complex cases with productive cough or purulent phlegm. The macrolide antibiotics, particularly second-generation agents such as dirithromycin and azithromycin, are among the antibiotic classes frequently recommended and used to treat upper and lower respiratory infections, including AECB.


OBJECTIVE
This study compared the clinical efficacy and tolerability of 5-day courses of dirithromycin and azithromycin given once daily for the treatment of acute exacerbations of chronic obstructive pulmonary disease (COPD).


METHODS
This randomized, investigator-blinded, parallel-group clinical trial was conducted at 5 centers in the United States. Eligible patients were adult (age >35 years) smokers or ex-smokers (smoking history of at least 10 pack-years) with chronic bronchitis and an acute exacerbation, defined by the occurrence of increased dyspnea and/or productive cough and feverishness within 48 hours of enrollment. Before randomization, an attempt was made to obtain a sputum specimen from each patient for Gram's staining and culture. Patients were randomized to receive dirithromycin 500 mg QD for 5 days or azithromycin 500 mg QD on day 1 and 250 mg QD on days 2 to 5. Clinical efficacy was assessed separately by patients and physicians at early (days 7-10) and late (days 25-35) posttreatment visits.


RESULTS
Eighty-six patients (48 women, 38 men; mean age, 55 years) with a mean smoking history of 31 pack-years were included in the intent-to-treat analysis. Forty-six (54%) patients were randomized to dirithromycin and 40 (47%) patients to azithromycin. Clinical efficacy was reported in a high proportion of patients in both treatment groups, both at the early posttreatment visit (84.8% dirithromycin, 75.7% azithromycin; difference dirithromycin - azithromycin, 9.1%; 95% CI, -8.2 to 26.4) and the late posttreatment visit (95.5% and 86.5%, respectively; difference dirithromycin - azithromycin, 9.0%; 95% CI, -3.7 to 21.6). A similar proportion of patients required a second course of antibiotics over the study period (20.5% dirithromycin, 27.0% azithromycin; difference dirithromycin - azithromycin, -6.6%; 95% CI, -25.2 to 12.1). Only 42 (48.8%) patients were able to produce a sputum sample before receiving study treatment, and of these, only 20 (47.6%) demonstrated a preponderance of neutrophils on Gram's staining. Both treatments were well tolerated.


CONCLUSIONS
The results of this study suggest comparable clinical efficacy between 5-day courses of once-daily dirithromycin and azithromycin in acute exacerbations of COPD. There were insufficient data to permit meaningful comparison of the bacteriologic efficacy of these macrolide antibiotics.
Castaldo
Richard S
RS
SUNY Buffalo School of Medicine, Buffalo, New York, USA.
Celli
Bartolome R
BR
Gomez
Fernando
F
LaVallee
Nicole
N
Souhrada
Joseph
J
Hanrahan
John P
JP
D000208:Acute Disease; D000284:Administration, Oral; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D017963:Azithromycin / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D004917:Erythromycin / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D018942:Macrolides; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy*; D016037:Single-Blind Method; D013997:Time Factors; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D018942:Macrolides; C053853:dirithromycin; D004917:Erythromycin; D017963:Azithromycin