Pharmacokinetics of cefotaxime and desacetylcefotaxime in patients with liver disease

Physiologically-Based Pharmacokinetic Modeling and Dosing Optimization of Cefotaxime in Preterm and Term Neonates

BACKGROUND

Cefotaxime is commonly used in treating bacterial infections in neonates. To characterize the pharmacokinetic process in neonates and evaluate different recommended dosing schedules of cefotaxime, a physiologically-based pharmacokinetic (PBPK) model of cefotaxime was established in adults and scaled to neonates.

METHODS

A whole-body PBPK model was built in PK-SIM® software. Three elimination pathways are composed of enzymatic metabolism in the liver, passive filtration through glomerulus, and active tubular secretion mediated by renal transporters. The ontogeny information was applied to account for age-related changes in cefotaxime pharmacokinetics. The established models were verified with realistic clinical data in adults and pediatric populations. Simulations in neonates were conducted and 100 % of the dosing interval where the unbound concentration in plasma was above the minimum inhibitory concentration (fT>MIC) was selected as the target index for dosing regimen evaluation.

RESULTS

The developed PBPK models successfully described the pharmacokinetic process of cefotaxime in adults and were scaled to the pediatric population. Good verification results were achieved in both adults' and neonates' PBPK models, indicating a good predictive performance. The optimal dosage regimen of cefotaxime was proposed according to the postnatal age (PNA) and gestational age (GA) of neonates. For preterm neonates (GA < 36 weeks), dosages of 25 mg/kg every 8 h in PNA 0-6 days and 25 mg/kg every 6 h in PNA 7-28 days were suggested. For term neonates (GA ≥ 36 weeks), dosages of 33 mg/kg every 8 h in PNA 0-6 days and 33 mg/kg every 6 h in PNA 7-28 days were recommended.

CONCLUSIONS

Our study may provide useful experience in practicing PBPK model-informed precision dosing in the pediatric population.

Dose optimization of cefotaxime as pre-emptive treatment in critically ill adult patients: A population pharmacokinetic study

AIMS

To describe the pharmacokinetics (PK) of cefotaxime as pre-emptive treatment in critically ill adult patients, including covariates and to determine the probability of target attainment (PTA) of different dosage regimens for Enterobacterales and Staphylococcus aureus.

METHODS

Five samples were drawn during 1 dosage interval in critically ill patients treated with cefotaxime 1 g q6h or q4h. PK parameters were estimated using NONMEM (v7.4.2). The percentage of patients reaching 100% fT>MIC_ECOFF was used to compare different dosage regimens for Enterobacterales and S. aureus.

RESULTS

This study included 92 patients (437 samples). The best structural model was a 2-compartment model with a combined error, interindividual variability on clearance, central volume and intercompartmental clearance. Correlations between interindividual variability were included. Clearance increased with higher estimated glomerular filtration rate (eGFR; creatinine clearance) and albumin concentration. For Enterobacterales, 1 g q8h reached 95% PTA and continuous infusion (CI) of 4 g 24 h^-1 100% PTA at the highest eGFR and albumin concentration. For S. aureus the predefined target of 95% PTA was not reached with higher eGFR and/or albumin concentrations. CI of 6 g 24 h^-1 for S. aureus resulted in a minimum of 99% PTA.

CONCLUSION

Cefotaxime PK in critically ill patients was best described by a 2-compartment model with eGFR and albumin concentration as covariates influencing clearance. For Enterobacterales 1 g q8h or CI of 4 g 24 h^-1 was adequate for all combinations of eGFR and albumin concentration. For S. aureus CI of 6 g 24 h^-1 would be preferred if eGFR and albumin concentration exceed 80 mL min^-1 and 40 g L^-1 respectively.

Antibiotics and Liver Cirrhosis: What the Physicians Need to Know

The liver is the primary site of drug metabolism, which can be altered by a variety of diseases affecting the liver parenchyma, especially in patients with liver cirrhosis. The use of antibiotics in patients with cirrhosis is usually a matter of concern for physicians, given the lack of practical knowledge for drug choice and eventual dose adjustments in several clinical scenarios. The aim of the current narrative review is to report, as broadly as possible, basic, and practical knowledge that any physician should have when approaching a patient with liver cirrhosis and an ongoing infection to efficiently choose the best antibiotic therapy.

Population pharmacokinetics of cefotaxime in intensive care patients

PURPOSE

To characterise the pharmacokinetics and associated variability of cefotaxime in adult intensive care unit (ICU) patients and to assess the impact of patient covariates.

METHODS

This work was based on data from cefotaxime-treated patients included in the ACCIS (Antibiotic Concentrations in Critical Ill ICU Patients in Sweden) study. Clinical data from 51 patients at seven different ICUs in Sweden, given cefotaxime (1000-3000 mg given 2-6 times daily), were collected from the first day of treatment for up to three consecutive days. In total, 263 cefotaxime samples were included in the population pharmacokinetic analysis.

RESULTS

A two-compartment model with linear elimination, proportional residual error and inter-individual variability (IIV) on clearance and central volume of distribution best described the data. The typical individual was 64 years, with body weight at ICU admission of 92 kg and estimated creatinine clearance of 94 mL/min. The resulting typical value of clearance was 11.1 L/h, central volume of distribution 5.1 L, peripheral volume of distribution 18.2 L and inter-compartmental clearance 14.5 L/h. The estimated creatinine clearance proved to be a significant covariate on clearance (p < 0.001), reducing IIV from 68 to 49%.

CONCLUSION

A population pharmacokinetic model was developed to describe cefotaxime pharmacokinetics and associated variability in adult ICU patients. The estimated creatinine clearance partly explained the IIV in cefotaxime clearance. However, the remaining unexplained IIV is high and suggests a need for dose individualisation using therapeutic drug monitoring where the developed model, after evaluation of predictive performance, may provide support.

Clinical characteristics and outcomes of spontaneous bacterial peritonitis caused by Enterobacter species versus Escherichia coli: a matched case-control study

Background

Enterobacter species are important nosocomial pathogens, and there is growing concern about their ability to develop resistance during antimicrobial therapy. However, few data are available on the clinical characteristics and outcomes of Enterobacter spontaneous bacterial peritonitis (SBP).

Methods

We retrospectively identified all patients with SBP caused by Enterobacter species admitted to a tertiary care hospital between January 1997 and December 2013. Each case was age- and sex-matched with four patients with Escherichia coli SBP.

Results

A total of 32 cases with Enterobacter SBP and 128 controls with E. coli SBP were included. Twenty-one (65.6 %) cases and 111 (86.7 %) controls had Child-Pugh class C (P = 0.006). Cases were significantly more likely to have hepatocellular carcinoma (65.6 % vs. 37.5 %, P = 0.004) and upper gastrointestinal bleeding (28.1 % vs. 9.4 %, P = 0.005). The initial response to empirical therapy (81.3 % vs. 81.2 %, P = 0.995) and the 30-day mortality (37.5 % vs. 28.9 %, P = 0.35) were not significantly different between the groups. Drug resistance emerged in one case and in no controls (4.3 % [1/23] vs. 0 % [0/98], P = 0.19).

Conclusions

Compared with E. coli SBP, patients with Enterobacter SBP more frequently had hepatocellular carcinoma and upper gastrointestinal bleeding, yet clinical outcomes were comparable. Development of resistance during third-generation cephalosporin therapy was infrequent in patients with Enterobacter SBP.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1595-y) contains supplementary material, which is available to authorized users.

Variability in plasma concentration of cefotaxime in critically ill patients in an Intensive Care Unit of India and its pharmacodynamic outcome: A nonrandomized, prospective, open-label, analytical study

BACKGROUND

Cefotaxime is a widely utilized cephalosporin in most intensive care units of India. However, no data are available about its pharmacokinetic/pharmacodynamic variability in critically ill patients of the Indian population.

AIM

To investigate the variability in the plasma concentration and pharmacodynamic profile of intermittent dosing of cefotaxime in critically ill patients, according to their locus of infection and causative organism.

MATERIALS AND METHODS

Cefotaxime levels were determined using high-performance liquid chromatography by grouping patients according to their locus of infection as hepatobiliary, renal, pulmonary, and others. Patients with cefotaxime concentration below the minimum inhibitory concentration (MIC) and 5 times below the MIC for the isolated organism were determined.

RESULTS

The difference in the plasma cefotaxime concentration between the hepatobiliary and the nonhepatobiliary groups was significant at 1 h (P = 0.02) following drug dosing, while the difference was significant between the renal and nonrenal group at 1 h (P = 0.001), 4 h (P = 0.009), and 8 h (P = 0.02) after drug dosing. The pulmonary group showed significantly (P < 0.05) lower plasma cefotaxime levels than the nonpulmonary group at all-time points. The cefotaxime levels were below the MIC and below 5 times the MIC for the isolated organism in 16.67% and 43.33% of the patients, respectively.

CONCLUSION

The concentration of cefotaxime differs according to the locus of an infection in critically ill patients. Use of another class of antibiotic or shifting to continuous dosing of cefotaxime, for organisms having MIC values above 1 mg/L, is advisable due to the fear of resistance.

Antibiotic treatment in patients with altered pathophysiological pathways

The pharmacokinetics of antibiotics are reviewed under particular physiological (senescence) and pathological (renal failure, liver failure) conditions. As regards the antibiotic management in the elderly, the main problems are related to the "immunosenescence" and to kinetic modifications, occurring even in the absence of an evident renal impairment. If manifest renal failure is present, the main issue is the correct dosage, and a careful consideration of the interest of the patient when they have to undergo hemodialysis. In cases of liver failure, a number of factors impairing the kinetics of antibiotics are discussed, underlining how these are too often underestimated in therapeutical approaches. The paper is focused on the behavior of new molecules, with particular regard to Teicoplanin, Carbapenems and Fluoroquinolones.

Cefotaxime. A reappraisal of its antibacterial activity and pharmacokinetic properties, and a review of its therapeutic efficacy when administered twice daily for the treatment of mild to moderate infections

Cefotaxime is well established as an effective and well tolerated antibacterial drug for 3 times daily parenteral treatment of a variety of moderate to severe infections in hospitalised patients. Its frequency of administration has recently been reassessed with a 12-hourly regimen. Comparative studies in hospitalised patients with nosocomial or community-acquired lower respiratory tract infections, demonstrate the similar clinical and bacteriological efficacy of twice daily cefotaxime 1 or 2 g and the same daily dose of ceftriaxone, usually administered once daily. Cefotaxime 2 g twice daily was also similar in efficacy to ceftriaxone 2 g once daily. Retrospective and post-marketing studies also reveal the similar efficacy of cefotaxime administered twice and 3 times daily, and pharmacoeconomic studies suggest that total direct costs of treatment with cefotaxime compared is similar to that with other third generation cephalosporins in currently used dosage regimens. When administered twice daily, cefotaxime is, thus, an effective antibacterial agent for the treatment of hospitalised patients outside the intensive care unit with a variety of mild to moderate non-CNS infections caused by susceptible organisms. When appropriately administered twice daily there is potential to lower the cost of antibacterial treatment without compromising efficacy.

Experience with cefotaxime in the treatment of spontaneous bacterial peritonitis in cirrhosis

Spontaneous bacterial peritonitis (SBP) is a severe infectious complication in cirrhotic patients, and initial antibiotic therapy must be empirical. An initial study published in 1985 found that cefotaxime administered at a dose of 2 g every 4 h was more effective and safer than the combination of tobramycin-ampicillin. Since then, cefotaxime has been considered the agent of choice in the empiric therapy of SBP. Subsequent publications showed that a dosage of 2 g every 6 h was also adequate in this infection. More recent studies have demonstrated that the high efficacy of cefotaxime in SBP can be maintained by using lower dosages than those used in initial investigations. In one of these studies, a dose of 2 g every 8 h for 5 days was found to be as effective as the same dose for 10 days. Finally, a prospective, randomized multicenter trial aimed at comparing the efficacy of two different dosages of cefotaxime, 2 g every 6 h versus 2 g every 12 in a large series of cirrhotic patients with SBP, showed that both dosages resulted in similar rates of resolution of infection and survival. Despite the reasonably adequate rate of infection resolution in SBP patients, the in-hospital mortality rate remains high as a result of complications such as renal failure. Further studies should therefore be addressed to reducing the incidence of these complications and thus improving survival.

Pharmacokinetics of cefotaxime in healthy volunteers and patients

Cefotaxime is a third-generation cephalosporin that has maintained good susceptibility pattern despite its extensive use. It is available for intravenous and intramuscular administration. Its pharmacokinetic property includes a small volume of distribution with low protein binding. Cefotaxime's half-life is approximately 1.1 h, and it is primarily eliminated by the kidney. It has an active metabolite desacetyl-cefotaxime that displays pharmacokinetic properties similar to cefotaxime. Desacetyl-cefotaxime has a half-life of 1.5 h and also is eliminated by the kidneys by both glomerular filtration and active secretion. The half-life of cefotaxime and its metabolite is altered in patients with severe renal dysfunction requiring dosage adjustment. Despite its relatively short half-life, cefotaxime may be dosed every 12 h based on its pharmacokinetic and pharmacodynamic properties.

Two different dosages of cefotaxime in the treatment of spontaneous bacterial peritonitis in cirrhosis: results of a prospective, randomized, multicenter study

Cefotaxime (CTX) is considered one of the first-choice antibiotics in the therapy of spontaneous bacterial peritonitis (SBP) in cirrhosis. Because CTX is largely metabolized in the liver, this drug may also be effective in SBP by administering lower doses than those habitually used. To investigate this possibility, a prospective, randomized, multicenter study was performed to compare the therapeutic efficacy of two different dosages of CTX in 143 patients with SBP: 71 (group I) were allocated to receive a high dose (2 g every 6 hours, which is one of the most frequently recommended doses in this infection), and 72 (group II) were allocated to receive a low dose (2 g every 12 hours). At inclusion, both groups were similar in relation to clinical and laboratory data, with the exception of a higher incidence of positive ascitic fluid culture in group I than in group II (59% vs. 40%; P = .029). The rate of infection resolution was similar for both groups (77% vs. 79%). Hospital survival was also similar in both groups (69% vs. 79%). No difference was observed between patients with positive or negative ascitic fluid cultures with regard to infection resolution and patient survival. The duration of antibiotic therapy was similar in both groups (9.0 +/- 3.3 days in group I vs. 8.8 +/- 3.1 days in group II). In a subset of 13 patients from group I and 11 patients from group II CTX levels were determined in serum (peak and trough) and ascitic fluid (concomitantly with trough serum). Peak serum levels were similar in patients from both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Antimicrobial activity of 11 newer and investigational drugs tested against aerobic isolates from spontaneous bacterial peritonitis

The in vitro susceptibility of 124 aerobic bacterial pathogens isolated from patients with spontaneous bacterial peritonitis (SBP) were tested against 11 antimicrobial agents, including parenteral or oral cephalosporins and fluoroquinolones. Most SBP isolates were Gram-negative organisms, and Escherichia coli and Klebsiella pneumoniae were responsible for 63% of the episodes evaluated. The fluoroquinolones (ciprofloxacin and ofloxacin) and the "fourth-generation" cephalosporin cefpirome were the most active agents against the Gram-negative bacteria. Commonly used cefotaxime and cefotaxime-desacetylcefotaxime (DES-CTX) combinations were also very active against Gram-negative bacteria with only few Enterobacter cloacae isolates being resistant (minimum inhibitory concentrations > 32 micrograms/ml). All streptococci were susceptible to cefotaxime, cefpirome, and cefdaloxime and to the cefotaxime-DES-CTX combinations, whereas only ofloxacin demonstrated acceptable activity against the enterococci. The widest spectrum of activity versus SBP isolates was found for ofloxacin (98% susceptibility) among the fluoroquinolones. For the beta-lactams, the widest spectrum of activity was demonstrated by cefpirome and the 2:1 cefotaxime-DES-CTX combination (93% susceptibility). These results indicate that the role of ofloxacin and newer parenteral or orally administered cephalosporins in the treatment of prophylaxis of SBP should be further evaluated.