hr-810 and Cystic-Fibrosis

Cefpirome is a new broad-spectrum beta-lactam antibiotic that exhibits minimal concentration dependent killing and produces prolonged postantibiotic effects only with Staphylococcus aureus. These pharmacodynamic characteristics suggest that the goal of optimal dosing regimens for cefpirome is to provide serum levels above the MIC of infecting pathogens for most of the dosing interval. Cefpirome has a half-life of 2.0 hours in normal volunteers that increases to 3.1 to 4.4 hours in elderly patients. Serum concentrations following 0.5, 1.0 and 2.0 grams of cefpirome are above the MIC of common pathogens for more than half of the dosing interval. For many of the Enterobacteriaceae, serum concentrations are above the MIC for over 12 hours. The drug distributes primarily into extracellular fluid and does provide potentially therapeutic concentrations in cerebrospinal fluid (CSF). The drug is eliminated primarily by the kidney and requires dosage modification when the creatinine clearance is below 50 ml/min. The half-life of the drug is not significantly altered in patients with cystic fibrosis and hepatic dysfunction. The integration of the drug's pharmacokinetic and pharmacodynamic characteristics support the use of a 12-hour dosing interval for the treatment of serious infection.

Topics: Adult; Age Factors; Aged; Bacteria; Cefpirome; Cephalosporins; Cystic Fibrosis; Drug Administration Routes; Drug Administration Schedule; Humans; Infections; Kidney Diseases; Liver Diseases; Middle Aged

Twenty two patients with inflammatory respiratory tract infection were treated with cefpirome. Among the patients 14 were with severe pneumonia, 4 with exacerbated obstructive chronic purulent bronchitis and 4 with mucoviscidosis. All the patients were subjected to clinical, laboratory and x-ray examinations, electrocardiography, estimation of the external respiration and sputum bacteriological tests. The cefpirome susceptibility was determined by the agar diffusion assay with standard disks from Roussel Uclaf. Cefpirome was administered by slow intravenous infusion in a daily dose of 2 to 4 g every 12 hours depending on the disease severity. After 2 or 3 days of the patient afebrile temperature and normal differential blood count the therapy was discontinued. The favourable time course of the disease was recorded in 12 out of the 14 patients with pneumonia. Recovery and clinical improvement were stated in 64.3 and 21.4 per cent of the cases respectively. In 2 patients the treatment failed. In all the patients with exacerbated severe chronic purulent bronchitis the cefpirome therapy resulted in the disease remission. The clinical effect of the mucoviscidosis treatment was observed in 3 out of the 4 patients. The drug tolerance in the doses used was good.

Topics: Adolescent; Adult; Aged; Bacterial Infections; Bronchitis; Cefpirome; Cephalosporins; Chronic Disease; Cystic Fibrosis; Female; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Pneumonia, Bacterial; Pseudomonas aeruginosa; Staphylococcus; Treatment Outcome

Cystic fibrosis (CF) patients are often reported to have higher clearances and larger volumes of distribution per kilogram of total body weight (WT) for beta-lactams than healthy volunteers. As pharmacokinetic (PK) data on cefpirome from studies of CF patients are lacking, we systematically compared its population PK and pharmacodynamic breakpoints for CF patients and healthy volunteers of similar body size. Twelve adult CF patients (median lean body mass [LBM] = 45.7 kg) and 12 healthy volunteers (LBM = 50.0 kg) received a single 10-min intravenous infusion of 2 g cefpirome. Plasma and urine concentrations were determined by high-performance liquid chromatography (HPLC). Population PK and Monte Carlo simulations were performed using NONMEM and S-ADAPT and a duration of an unbound plasma concentration above the MIC ≥ 65% of the dosing interval as a pharmacodynamic target. Unscaled clearances for CF patients were similar to those seen with healthy volunteers, and the volume of distribution was 6% lower for CF patients. Linear scaling of total clearance by WT resulted in clearance that was 20% higher (P ≤ 0.001 [nonparametric bootstrap]) in CF patients. Allometric scaling by LBM explained the differences between the two subject groups with respect to average clearance and volume of distribution and reduced the unexplained between-subject variability of renal and nonrenal clearance by 10 to 14%. For the CF patients, robust (>90%) probabilities of target attainment (PTA) were achieved by the administration of a standard dose of 2 g/70 kg WT every 12 h (Q12h) given as 30-min infusions for MICs ≤ 1.5 mg/liter. As alternative dosage regimens, a 5-h infusion of 1.33 g/70 kg WT Q8h achieved robust PTAs for MICs ≤ 8 to 12 mg/liter and a continuous infusion of 4 g/day for MICs ≤ 12 mg/liter. Prolonged infusion of cefpirome is expected to be superior to short-term infusions for MICs between 2 and 12 mg/liter.

Topics: Adolescent; Adult; Anti-Bacterial Agents; Body Size; Cefpirome; Cephalosporins; Cystic Fibrosis; Female; Humans; Male; Microbial Sensitivity Tests; Monte Carlo Method