Beta-lactam allergy in adults with cystic fibrosis.

BACKGROUND: Allergic reactions to one or more beta-lactam antibiotic can pose a management problem in patients with cystic fibrosis (CF), and may limit antibiotic choice. METHOD: The aim of this study was to assess the prevalence of allergy to anti-pseudomonal beta-lactam antibiotics in an adult CF centre and to assess variables, which may contribute to the development of allergic reactions. A questionnaire-based interview and a review of medical records were performed. RESULTS: Of the 150 patients, 54 (36%) had allergic reactions to one or more beta-lactam antibiotics and 20 (19%) had allergic reactions to multiple beta-lactam antibiotics. The proportion of patients allergic to specific beta-lactam antibiotics varied from 10% to 26%. Rates of reactions were highest for penicillins and cephalosporins, intermediate for carbepenems and lowest for aztreonam. Of all reactions, 40% occurred within 24 h of the commencement of an individual antibiotic course. Patients with one or more beta-lactam allergic reactions had received greater cumulative exposure (p<0.0001), were older (p=0.016) and had lower lung function (p=0.037) than patients without a history of beta-lactam allergy. Cystic Fibrosis transmembrane regulator (CFTR) status, gender, peripheral blood eosinophil count and total IgE concentrations were not different in patients with allergic reactions. CONCLUSIONS: This study demonstrates that the prevalence of allergic reactions to beta-lactam antibiotics is high in adults with CF. Increasing age; cumulative exposure and decreasing FEV(1) were associated with the development of allergy.

Antibiotic desensitization in adults with cystic fibrosis.

OBJECTIVE: Allergic reactions to antibiotics occur in up to 30% of patients with cystic fibrosis (CF). Repeated antibiotic exposure and immune hyper-responsiveness increase the risk of allergic reactions and may limit antibiotic choice. Desensitization may allow the successful administration of an antibiotic despite previous allergy. We aimed to determine the success of antibiotic desensitization in patients with CF in an adult CF unit over a 7-year period. METHODOLOGY: A retrospective medical record review was performed on the 19 patients who had undergone antibiotic desensitization procedures. Data collected included drug allergy and intolerance profiles, nature of allergies, and the outcome of desensitization procedures. Desensitization procedures were performed in a ward setting according to published methods. RESULTS: Nineteen patients (13 females) reported 62 drug allergies with a mean of 3.3 per patient. Of the 71 desensitization procedures undergone by this group, 54 (76%) were successful. Fifteen of the 19 patients were allergic to two or more beta-lactam antibiotics. Over half of the patients were desensitized to more than one antibiotic. Nine different antibiotics were used in 31 different patient/drug combinations. A successful outcome was achieved in 18/31 (58%) combinations, with three requiring treatment for mild allergic reactions. Allergic reactions caused drug cessation in a total of 19 patient/drug combinations (three after initial successful desensitization and full courses of antibiotics). Over 50% of these reactions occurred on day 1. Desensitization failures were more common in patients with well-documented allergic reactions to a specific drug. CONCLUSION: This study demonstrates that multiple antibiotic allergies are common in adults with CF. Cross-reactivity between beta-lactam antibiotics may limit antibiotic choice for the treatment of pulmonary exacerbations. Antibiotic desensitization allows safe and successful treatment in the ward setting of many patients with previous allergies to an antibiotic. In many patients symptoms of allergy still occur and result in cessation of the antibiotics. Use of corticosteroids and antihistamines may improve the success rate of desensitization procedures.

Nebulised dornase alpha: adherence in adults with cystic fibrosis.

BACKGROUND: Dornase alpha improves sputum clearance and pulmonary function in patients with moderate bronchiectasis and cystic fibrosis (CF). Several studies have demonstrated variable adherence to treatment regimens in patients with CF. We aimed to compare self-reported adherence with computer based dispensing records of dornase alpha. METHOD: Direct interview of adherence to dornase alpha was compared with pharmacy-dispensing records during a 12-month period. The reasons for dornase alpha usage, and change in lung function in three groups of patients were compared (group 1 (n=42): positive trial, continuing therapy; group 2 (n=13): positive trial, ceased therapy; group 3 (n=22): negative trial). Ninety patients with CF were surveyed. Patients who had ceased dornase alpha provided reasons for drug cessation. Lung function and anthropometric data were collected prior to dornase alpha treatment and at 3 years. Health care professionals rated adherence to therapy. RESULTS: Of the 42 patients on dornase alpha, the average utilisation was 197 days (54%). From dispensing records, 24% of patients were classified as good adherence, 46% as moderate adherence and 30% as poor adherence. Eighty-two percent claimed to use dornase alpha therapy more than 20 days/month, whereas dispensing records showed that only 24% of collected sufficient drug supplies. Health professionals' assessment of adherence of therapy was often incorrect and an overestimation was more common than underestimation. The change in FEV(1) 3 years after trial was not significantly different between groups. There was a negative correlation between initial response to dornase alpha and baseline FEV(1) (r=-0.44, P=0.001), however, initial response was not related to the change in FEV(1) over 3 years (r=0.20, P=0.16). CONCLUSION: There is variability in adherence to dornase alpha in adults with CF and patient self-reporting is likely to over-estimate drug collection from the pharmacy. Further study of the long-term effects of dornase alpha is required. To date, proven interventions to enhance adherence are limited and require investigation in CF.