Prophylactic antibiotics for cystic fibrosis.

BACKGROUND: Patients with cystic fibrosis are sometimes prescribed antibiotics to take continuously on a prophylactic (preventative) basis. This approach is most commonly used in infants where the objective is to reduce pulmonary infection with Staphylococcus aureus and prevent lung damage. This approach may also be used in older patients. This review evaluates the evidence for the effectiveness of this approach and considers potential adverse effects. OBJECTIVES: To compare continuous oral antibiotic prophylaxis with no prophylaxis (short courses of oral antibiotics given as clinically indicated) in patients with cystic fibrosis. This review considers both the effectiveness of prophylaxis (bacteria isolated from the respiratory tract, requirement for additional antibiotic treatment, lung function, survival) and the adverse effects. SEARCH STRATEGY: The Cochrane Cystic Fibrosis and Genetic Disorders Group clinical trials register was used. This comprises references identified from a comprehensive search of electronic databases, as well as hand searching relevant journals and conference abstracts. Companies manufacturing anti-staphylococcal antibiotics were also approached for unpublished data. Date of the most recent search of the Group's specialised register: November 1999. SELECTION CRITERIA: All randomised or pseudo-randomised trials where continuous oral prophylactic antibiotics, given for a period of at least one year, were compared to intermittent antibiotic therapy given "as required." Cystic fibrosis patients of any disease severity were considered. DATA COLLECTION AND ANALYSIS: Trials were assessed for eligibility, methodological quality and data extraction by two reviewers (AS & SW). The following outcomes were assessed: lung function; nutrition (weight standard deviation score); survival; requirement for additional antibiotic treatment; isolates of pathogens from the respiratory tract; occurrence of adverse reactions to prophylactic antibiotics. MAIN RESULTS: Only two studies, totalling 66 patients (over half of whom were infants), were suitable for inclusion in the review. A reduced prevalence of Staphylococcus aureus in the respiratory secretions was seen in children receiving anti-staphylococcal antibiotic prophylaxis, although no effect was seen on other common pathogens. This is associated with a reduced requirement for additional courses of oral antibiotics and fewer hospital admissions in the first two years of life in patients receiving prophylaxis. No effect on infant lung function has been shown after one year of prophylactic treatment. Data are not available on adverse effects of the interventions. As the duration of the studies reviewed has been of two years or less, conclusions cannot be drawn about the long term effects of prophylaxis on acquisition of Pseudomonas aeruginosa and survival. REVIEWER' S CONCLUSIONS: Anti-staphylococcal antibiotic prophylaxis may be of benefit when commenced early in infancy and continued up to two years of age. There is insufficient evidence from this review to say whether use in older children, or adults, or for periods of over two year is beneficial.