Four randomised, placebo-controlled trials have previously documented the clinical benefits of azithromycin (AZM) in cystic fibrosis (CF) patients. The present study examined whether the beneficial effect of AZM is equivalent when administered daily or weekly.A double-blind, randomised study was carried out in 208 CF patients aged 6-58 yrs who were assigned to AZM either 250 mg daily (n5103) or 1,200 mg weekly (n5105) for 6 months, with assessments at baseline and at 1, 3, 6 and 7 months. Patients were taken from five adult and children CF centres in South-east Queensland, Australia.Equivalence was demonstrated between the two groups (daily versus weekly) with respect to improvements in lung function (forced expiratory volume in one second and forced vital capacity), C-reactive protein, days spent in hospital, admission rates and nutrition (body mass index, zscores) using 95% confidence intervals with a tolerance interval of ¡10%.In patients aged ,18 yrs the daily group had significantly better improvements in z-scores for height and weight after 6 months. In children, a nutritional advantage for daily administration was found. Gastro-intestinal adverse effects were more common with weekly therapy. Apart from these findings, daily and weekly administered azithromycin demonstrated similar outcomes for cystic fibrosis patients.

Macrolide antibiotics have been licensed since the 1950s and have an important role in the treatment of a diverse range of infectious diseases. Macrolide antibiotics have antibacterial activity against gram-positive bacteria, some gram-negative bacteria and intracellular pathogens. The spectrum of antibacterial activity combined with excellent intracellular and tissue penetration has led to the extensive use of this class of drugs in respiratory disease. Macrolide antibiotics also have demonstrated anti-inflammatory properties in various in vitro and in vivo model systems. Novel antimicrobial and anti-inflammatory properties of macrolide may result in clinical benefits, particularly in conditions where the infectious agent is inherently resistant to macrolides. Three randomized control trials have demonstrated improved lung function in patients treated with the macrolide antibiotic, azithromycin. Azithromycin was generally well tolerated and resulted in reduction in the inflammatory response which may be due to an immunomodulatory role. Short term studies (three to six months) have not demonstrated the development of increased bacterial resistance or the emergence of new pathogens following azithromycin.