Pharmacokinetics of ceftriaxone in plasma and bone of patients undergoing hip or knee surgery

Intra-operative drug level monitoring of pre-operative antibiotic for surgical prophylaxis in the patients of elective spinal surgery

OBJECTIVES

Single dose prophylaxis is good enough for general surgery with low risk patients. However, the evidence for the effectiveness of single dose anti-microbial prophylaxis (AMP) is not conclusive in high risk patients and spinal surgeries requiring instrumentation or the use of implants in particular. No studies have explored the various concentration of ceftriaxone in plasma and tissue as well during an ongoing spinal surgery. Therefore, the objective of study was to correlate the serum and tissue concentrations of ceftriaxone with the SSI and identify patients with increased risk of SSI.

METHODS

It was an open label prospective study in 50 consecutive patients who underwent elective spine surgery under prophylactic cover of ceftriaxone. Serum and tissue concentration were estimated by high pressure liquid chromatography during the ongoing surgery.

RESULTS

Subjects were observed for any post-operative complications including SSI. Serum (p=0.002) and tissue (p=0.012) concentrations of ceftriaxone at the closure of spinal surgery were associated with SSI. Duration of the surgery (p=0.04) and use of implants (p=0.02) were also important surgery related risk factors.

CONCLUSIONS

Serum and tissue concentrations of ceftriaxone at the closure and duration of surgery and instrumentation or use of implants in the spinal surgery are good predictors of SSI.

Tissue Penetration of Antimicrobials in Intensive Care Unit Patients: A Systematic Review—Part I

The challenging severity of some infections, especially in critically ill patients, makes the diffusion of antimicrobial drugs within tissues one of the cornerstones of chemotherapy. The knowledge of how antibacterial agents penetrate tissues may come from different sources: preclinical studies in animal models, phase I–III clinical trials and post-registration studies. However, the particular physiopathology of critically ill patients may significantly alter drug pharmacokinetics. Indeed, changes in interstitial volumes (the third space) and/or in glomerular filtration ratio may influence the achievement of bactericidal concentrations in peripheral compartments, while inflammation can alter the systemic distribution of some drugs. On the contrary, other antibacterial agents may reach high and effective concentrations thanks to the increased tissue accumulation of macrophages and neutrophils. Therefore, the present review explores the tissue distribution of beta-lactams and other antimicrobials acting on the cell wall and cytoplasmic membrane of bacteria in critically ill patients. A systematic search of articles was performed according to PRISMA guidelines, and tissue/plasma penetration ratios were collected. Results showed a highly variable passage of drugs within tissues, while large interindividual variability may represent a hurdle which must be overcome to achieve therapeutic concentrations in some compartments. To solve that issue, off-label dosing regimens could represent an effective solution in particular conditions.

Turbidimetric Method: A Multi-Advantageous Option for Assessing the Potency of Ceftriaxone Sodium in Powder for Injection

BACKGROUND

Ceftriaxone sodium, an antimicrobial used in parenteral form, does not have a microbiological method by turbidimetry described in the literature. For drugs from antimicrobial class, the existence of a microbiological method for assessing their potency is essential. Not only are the results from the physical-chemical methods enough, but microbiological analyzes are also necessary.

OBJECTIVE AND METHODS

Thus, this paper reports the development and validation of an efficient, accurate, reproducible, fast, and low-cost microbiological assay by turbidimetry to quantify ceftriaxone sodium in powder for injection. Water was used as the diluent to prepare the ceftriaxone solutions. BHI broth as used as culture media for the growth of the S. aureus ATCC 6538 at 9%.

RESULTS

The method was linear in the range of 100-196 µg/mL, selective against the sample adjuvants and the forced degradation test, precise (intraday RSD 4.53%, interday RSD 3.85% and between analysts tcalculated 0.14 < 2.23 tcritical), accurate with recovery of 100.33% and robust against minor changes in the volume of culture medium used, wavelength, incubation time, and inoculum concentration.

CONCLUSIONS AND HIGHLIGHTS

The turbidimetric method developed in this paper is a convenient and valuable alternative to the routine quality control of ceftriaxone sodium in powder for injection, since it allows a reliable quantification and can be used to complement the physical-chemical analysis.

Rapidly fatal pneumococcal meningitis following non-penetrating traumatic brain injury

A previously healthy young man presented to hospital with severe traumatic brain injury following a motor vehicle collision. Within 24 hours of admission, and despite antibiotic coverage, he developed a fever. On the second day, the source of infection was discovered to be purulent pneumococcal meningitis. At 48 hours post-accident, he developed brain-stem death without evidence of raised intracranial pressure or trans-tentorial herniation. Initial CT scans of the head were essentially normal, but early repeat scans revealed evidence of pneumocephalus and possible frontal bone fracture. Current recommendations do not make room for targeted antibiotic prophylaxis in traumatic brain injury patients with traumatic skull fracture. We argue that our case demonstrates the need for aggressive targeted antibiotic prophylaxis in the presence of certain features such as frontal or sphenoid bone fracture and pneumocephalus.

Population pharmacokinetics of cefuroxime and uptake into hip and spine bone of patients undergoing orthopaedic surgery

OBJECTIVES

To reduce the incidence of peri- or postoperative infections in orthopaedic surgery, patients are prophylactically treated with antibiotics. Here, we wanted to know whether effective bone and intervertebral disc concentrations of cefuroxime are reached.

METHODS

Patients undergoing surgery of hip (N = 40; 62.5% male) or spine (N = 40; 55% male) were pretreated with 1.5 g of the second-generation cephalosporin cefuroxime before surgery. We studied plasma population kinetics and bone and intervertebral disc (C5/6 till L5/S1) concentrations of cefuroxime using high-performance liquid chromatography.

KEY FINDINGS

The plasma kinetics of cefuroxime in 80 patients was analysed using a population approach. The clearance amounted to 7.86 l/h. The peripheral and central volumes of distribution were estimated as 8.45 and 10.4 l, respectively. The concentrations in hip samples amounted to 9.8 ± 0.6 µg/g in cancellous bone and 8.9 ± 0.8 µg/g in cortical bone. Cefuroxime concentrations in vertebral bone and intervertebral discs were calculated as 9.6 ± 1.3 and 8.9 ± 1.1 µg/g, respectively.

CONCLUSION

Even if a majority of patients undergoing hip or spine surgery probably achieved adequate concentrations of cefuroxime, not all patients reached bone concentrations of cefuroxime above a recommended breakpoint for susceptible germs at the time of surgery.

Target site antibiotic concentrations in orthopedic/trauma extremity surgery: is prophylactic cefazolin adequately dosed? A systematic review and meta-analysis

Background and purpose - The incidence of surgical site infections (SSIs) in trauma/orthopedic surgery varies between different body parts. Antibiotic prophylaxis (e.g., with cefazolin) lowers infection rates in closed fracture surgery and in primary arthroplasty. For prophylactic antibiotics to prevent infections, sufficient concentrations at the target site (location of surgery) are required. However, dosage recommendations and the corresponding efficacy are unclear. This review assesses target site cefazolin concentrations and the effect of variation in dose and location of target site during orthopedic extremity surgery. Methods - For this meta-analysis and systematic review, the literature was searched using the following keywords: "cephalosporins," "orthopedic," "extremity," "surgical procedures," and "pharmacokinetics". Trials measuring target site antibiotic concentrations (bone, soft tissue, synovia) during orthopedic surgery after a single dose of cefazolin were included. Results - The search identified 14 studies reporting on concentrations in the shoulder (n = 1), hip (n = 8), knee (n = 8), or foot (n = 1). A large variation was seen between studies, but the pooled results of 4 studies showed higher concentrations in hip than in knee (mean difference: 4 ug/g, 95% CI 0.8-7). Articles comparing different doses of cefazolin reported higher bone concentrations after 2 g than before, but pooling results did not lead to a statistically significant difference. Interpretation - Although not all results could be pooled, this study shows that cefazolin concentrations are higher in the hip than in the knee. These findings suggest that the dose of prophylactic cefazolin might not be sufficient in distal parts of the extremity. Further research should investigate whether a higher dose of cefazolin can lead to higher concentrations and fewer SSIs.

Use of regional administration of prophylactic antibiotics in total knee arthroplasty

Prosthetic joint infection after total knee arthroplasty is an infrequent, yet serious complication. Antimicrobial prophylaxis plays an important role in reducing the rate of surgical site infections. To be effective as an antimicrobial prophylaxis, the serum, tissue and bone concentrations of the antibiotic must be greater than the target organism's minimum inhibitory concentration. As antibiotic resistance increases current intravenous prophylactic dosing has been shown to be subtherapeutic for some patients. Intravenous regional administration and intraosseous regional administration of prophylactic antibiotics are novel methods used to increase the antibiotic tissue concentrations, which may enhance the efficacy of prophylactic antibiotics in total knee arthroplasty. Currently, literature has shown both intravenous regional administration and intraosseous regional administration to be safe and effective techniques. However, there is no clinical evidence to show that it results in a reduction of prosthetic joint infection rates. This study summarizes the current knowledge base on the use of regional administration of prophylactic antibiotics in total knee arthroplasty.

A Critical Review of Analytical Methods for Determination of Ceftriaxone Sodium

Ceftriaxone sodium is a third-generation semi-synthetic antibiotic belonging to the class of cephalosporins. Is administered only by parenteral route and has the ability to cross the blood-brain barrier. It has bactericidal action; its main activity is related to the Gram-negative bacteria, being also able to act against Gram-negative bacilli resistant to the first- and second-generation cephalosporins. The present study presents a survey of the characteristics, properties and analytical methods used for the determination of ceftriaxone sodium, for the gathering of data searches were carried out in scientific articles in the world literature, as well as in the official compendia. It is necessary to create awareness about the importance of developing effective and reliable analytical methods for quality control and consequently for conducting pharmacokinetic, bioavailability, bioequivalence studies as well as for the therapeutic monitoring of this drug. Most of the methods found use high-performance liquid chromatography, but also methods that use absorption spectroscopy ultraviolet, infrared spectroscopy, spectrofluorimetry and microbiological methods have been presented. A discussion was presented highlighting the need to develop new ecological methods using less toxic solvents, rapid analysis and miniaturization of the samples.

Population Pharmacokinetics of Levofloxacin in Plasma and Bone of Patients Undergoing Hip or Knee Surgery

Patients undergoing hip or knee replacement therapy are routinely pretreated with antibiotics before they enter the operation theater. This treatment intends to reduce the incidence of peri- or postsurgical infections. Here, we calculated the uptake kinetics of levofloxacin into bone to see whether levofloxacin could be obtained from the trabecular and cortical bone and at what time concentrations are sufficiently high to inhibit the usual hospital infections. Patients (n = 42) undergoing routine surgery were treated with 500 mg levofloxacin intravenously immediately prior to the operation. Plasma samples were taken before and at 3 points after termination of drug infusion. After replacement of the bones, extracts were obtained from them. Levofloxacin was quantified using high-performance liquid chromatography. The kinetics of levofloxacin and its distribution into bone were analyzed using a population approach (ADAPT5). Clearance was 14.0 L/h, and distribution volume was 77 L. Bone uptake t½ was calculated as 4.2 and 5.4 hours for cortical bone and trabecular bone, respectively. In knee samples (but not in hip samples), we noted that the cortical bone contained higher levels of levofloxacin than the trabecular bone. From our data, we can conclude that levofloxacin might be useful for prophylactic use in bone surgery.