Biliary excretion of cefixime: assessment in patients provided with T-tube drainage

Clinical pharmacokinetic of cefixime: a systematic review

Cefixime is an antibiotic from the cephalosporin class used to treat various bacterial infections. The purpose of performing this review is to thoroughly evaluate the pharmacokinetic (PK) data on cefixime.Five databases were systematically searched to identify studies on the PK of cefixime.A total of 38 articles meeting the eligibility criteria were included that provide data on concentration-time profiles or PK parameters such as peak plasma and serum concentration (C_max), area under the curve (AUC), clearance (CL), and time to reach C_max (t_max). A dose-dependent increase in AUC and Cmax of cefixime was depicted in healthy volunteers. The clearance of cefixime decreased according to the degree of renal insufficiency among haemodialysis patients. A significant difference in CL was found in comparing fasted and fed states. A biphasic decline in serum concentrations of cefixime was reported when it was taken without probenecid.This review compiles all the reports on the PK of cefixime in healthy and renally impaired patients; the summarized information can be used to optimize cefixime dosing in different disease states. Moreover, cefixime has increased time above MIC value suggesting that it may be an effective treatment for infections caused by certain pathogens.

Role of cephalosporins in the era of Clostridium difficile infection

The incidence of Clostridium difficile infection (CDI) in Europe has increased markedly since 2000. Previous meta-analyses have suggested a strong association between cephalosporin use and CDI, and many national programmes on CDI control have focused on reducing cephalosporin usage. Despite reductions in cephalosporin use, however, rates of CDI have continued to rise. This review examines the potential association of CDI with cephalosporins, and considers other factors that influence CDI risk. EUCLID (the EUropean, multicentre, prospective biannual point prevalence study of CLostridium difficile Infection in hospitalized patients with Diarrhoea) reported an increase in the annual incidence of CDI from 6.6 to 7.3 cases per 10 000 patient bed-days from 2011-12 to 2012-13, respectively. While CDI incidence and cephalosporin usage varied widely across countries studied, there was no clear association between overall cephalosporin prescribing (or the use of any particular cephalosporin) and CDI incidence. Moreover, variations in the pharmacokinetic and pharmacodynamic properties of cephalosporins of the same generation make categorization by generation insufficient for predicting impact on gut microbiota. A multitude of additional factors can affect the risk of CDI. Antibiotic choice is an important consideration; however, CDI risk is associated with a range of antibiotic classes. Prescription of multiple antibiotics and a long duration of treatment are key risk factors for CDI, and risk also differs across patient populations. We propose that all of these are factors that should be taken into account when selecting an antibiotic, rather than focusing on the exclusion of individual drug classes.

Effects of surgery on the pharmacokinetic parameters of drugs

As with other forms of stress, surgery is a time of fluctuating haemodynamics, physiological shifts, intense metabolic changes, and protein catabolism and anabolism. At times, these changes can occur within hours. There is a reasonable body of literature concerning the adverse effects of surgery on gastric emptying, but not on the effects of surgery on the distribution, metabolism and excretion of drugs. Gastric emptying is diminished or absent following major procedures, which prevent the delivery of orally administered drugs to their major site of absorption, the small bowel. Changes in the paracellular absorption of drugs may occur postoperatively, although transcellular absorption appears to be unimpaired. Distribution is affected by changes in blood volume, alterations in circulation, increases in the extracellular fluid and changes in the circulating plasma protein levels, such as albumin and alpha 1-acid glycoprotein. Little is known about alterations in drug metabolism following surgery. However, it has been shown that systemic hypoxia alters the function of some of the cytochrome P450 (CYP) system and increased levels of cytokines have an effect on the metabolism of at least 1 drug. In addition, the renal elimination of drugs is affected in patients postoperatively, although the effects of biliary clearance in this period are difficult to determine. Despite the lack of research into pharmacokinetics during the postoperative period, and given the immense and often sudden changes observed in patients post-surgery, it is reasonable to recommend vigilance with respect to drug therapy during this period.

Assessment of biliary excretion of piperacillin-tazobactam in humans

Piperacillin-tazobactam concentrations in serum and bile were measured intraoperatively in 10 patients undergoing cholecystectomy (group 1) and 5 cholecystectomized patients provided with external bile duct drainage (group 2). Each patient received a single intravenous dose of piperacillin at 4 g plus tazobactam at 0.5 g over 30 min. Drug concentrations in both serum and bile were measured by high-performance liquid chromatography. In group 1 patients, serum and bile specimens and gallbladder wall fragments were collected at mean times of 70 and 83 min postinfusion, respectively. The mean concentrations of piperacillin and tazobactam were, respectively, 69.1 +/- 41.5 (standard deviation) and 9.9 +/- 5.1 microg/ml in serum, 630.4 microg/ml (range, 24.8 to 1,194 microg/ml) and 11.8 microg/ml (range, 3.6 to 22 microg/ml) in choledochal bile, 342.3 microg/ml (range, 1.1 to 1,149 microg/ml) and 7.7 microg/ml, (range, 0.2 to 23.1 microg/ml) in gallbladder bile, and 49.3 microg/g (range, 9.7 to 223 microg/g) and 2.9 microg/g (range, 0.1 to 5.9 microg/g) in the gallbladder wall. In group 2 patients, the amounts of drugs recovered in bile drainage obtained over 12 h were 28.4 +/- 18.0 and 1.0 +/- 0.5 mg for piperacillin and tazobactam, respectively. Peak piperacillin and tazobactam concentrations in bile reached 358 +/- 242 and 10.8 +/- 4.2 microg/ml, respectively. Comparison of drug levels in serum and bile suggests an underlying active secretion process for piperacillin elimination into the bile, unlike that of tazobactam. From a therapeutic viewpoint, given the concentrations of tazobactam recorded in bile fluid and tissue, the addition of this beta-lactamase inhibitor to piperacillin therapy might be of interest in the management of biliary tract infections, mostly in patients at risk of mixed aerobic-anaerobic infections due to beta-lactamase-producing organisms.