Evaluation of the safety of piperacillin/tazobactam use in admitted pediatric patients with cystic fibrosis

Background: Piperacillin/tazobactam (PT) is a first-line antibiotic for Pseudomonas aeruginosa (PsA) respiratory infections in patients with cystic fibrosis (CF), but increased adverse reactions (ARs) have been reported in these patients. We aimed to determine the incidence of and risk factors for ARs to PT within the pediatric CF population. Methods: We conducted a retrospective analysis of CF patients at a pediatric tertiary care centre who had received PT and compared ARs associated with PT versus other antipseudomonal antibiotics. Results: Of the 26 patients who received PT, the PT AR prevalence was n=7 (27%); 3 patients developed fever and rash, 2 had only fever, 1 had only rash, and 1 had fever, rash, and severe neutropenia. The following variables were associated with fever following PT administration: younger age (8.46 versus 13.15 years, p=0.02), fewer previous admissions for CF pulmonary exacerbation (1.67 versus 7.25, p=0.03), and increased PT dose (386.37 versus 270.73 mg/kg/day, p=0.02). Younger age was also associated with increased overall AR to PT (9.6 versus 13.3 years, p=0.04). Increased PT dose was associated with fever (OR 1.02 (1.00–1.05), p=0.03) and with overall reactions (OR 1.01 (1.00–1.02), p=0.03). Comparing incidence rates of ARs following PT and ticarcillin/clavulanate resulted in a trend toward increased relative reaction to PT, but confidence intervals (CIs) were not significant. Conclusions: We found a high AR rate associated with PT, and an association between increased dose and fever and overall ARs.