hr-810 and Infections

Several reports have shown marked heterogeneity of antibiotic pharmacokinetics (PK) in patients admitted to ICUs, which might potentially affect outcomes. Therefore, the pharmacodynamic (PD) parameter of the efficacy of β-lactam antibiotics, that is, the time that its concentration is above the bacteria minimal inhibitory concentration (T > MIC), cannot be safely extrapolated from data derived from the PK of healthy volunteers.. We performed a full review of published studies addressing the PK of intravenous β-lactam antibiotics given to infected ICU patients. Study selection comprised a comprehensive bibliographic search of the PubMed database and bibliographic references in relevant reviews from January 1966 to December 2010. We selected only English-language articles reporting studies addressing β-lactam antibiotics that had been described in at least five previously published studies. Studies of the PK of patients undergoing renal replacement therapy were excluded.. A total of 57 studies addressing six different β-lactam antibiotics (meropenem, imipenem, piperacillin, cefpirome, cefepime and ceftazidime) were selected. Significant PK heterogeneity was noted, with a broad, more than twofold variation both of volume of distribution and of drug clearance (Cl). The correlation of antibiotic Cl with creatinine clearance was usually reported. Consequently, in ICU patients, β-lactam antibiotic half-life and T > MIC were virtually unpredictable, especially in those patients with normal renal function. A better PD profile was usually obtained by prolonged or even continuous infusion. Tissue penetration was also found to be compromised in critically ill patients with septic shock.. The PK of β-lactam antibiotics are heterogeneous and largely unpredictable in ICU patients. Consequently, the dosing of antibiotics should be supported by PK concepts, including data derived from studies of the PK of ICU patients and therapeutic drug monitoring.

Topics: Anti-Bacterial Agents; beta-Lactams; Cefepime; Cefpirome; Ceftazidime; Cephalosporins; Critical Illness; Humans; Imipenem; Infections; Meropenem; Piperacillin; Thienamycins

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