Vancomycin pharmacokinetics during continuous ambulatory peritoneal dialysis in patients with peritonitis

Vancomycin Dosing Strategy for the Treatment of Peritonitis in a Child on Automated Peritoneal Dialysis: A First Pediatric Case Report

BACKGROUND

Bacterial peritonitis is a common complication of peritoneal dialysis. In the absence of systemic signs of infection, adult guidelines recommend treatment with intraperitoneal vancomycin either as empiric coverage of gram-positive organisms or as targeted therapy. However, there is no guidance on how to administer vancomycin in children on automated peritoneal dialysis.

CASE REPORT

We report vancomycin pharmacokinetics upon intraperitoneal administration for the treatment of a Staphylococcus hominis peritonitis in an 11-year-old patient on automated nocturnal intermittent peritoneal dialysis. While the patient was hospitalized, vancomycin was administered intraperitoneally as a continuous treatment. After hospital discharge, the nocturnal peritoneal dialysis was resumed. In the absence of treatment guidelines, intraperitoneal vancomycin was initially administered empirically only during the nocturnal dialysis exchanges which led to repetitive subtherapeutic vancomycin plasma concentrations and the persistence of S. hominis in dialysate cultures. Based on studies in adults, the dosing strategy was subsequently modified to administer vancomycin at a dosage of 15 mg kg-1 in the dialysate with a 6-h dwell period prior to the nocturnal dialysis thereby allowing to reach optimal peak concentrations. The dosing interval was subsequently individualized using therapeutic drug monitoring to ensure residual vancomycin concentrations > 10 mg L-1 thereby leading to clinical and microbiological recovery.

CONCLUSIONS

This case presents a dosing strategy based on a comprehensive review of the literature and highlights that a sufficient dwell period is critical when treating pediatric patients on automated peritoneal dialysis in order to allow vancomycin distribution and equilibration between the dialysate and the plasma.

Vancomycin flushing reaction after intraperitoneal vancomycin: A case report

Vancomycin has been reported to cause vancomycin flushing reaction (VFR), a hypersensitivity reaction that mostly occurs after intravenous administration. The incidence of VFR in a patient receiving intraperitoneal vancomycin is rare. We report a case of a female peritoneal dialysis (PD) patient with a PD-related peritonitis who developed VFR after intraperitoneal administration of 2000 mg vancomycin. Seventy-five minutes after instillation, she developed flushing, a pruritic erythema on the upper body and swelling of the lips. Blood results revealed a vancomycin plasma concentration of 54.8 mg/L and a normal tryptase level. During a relapse of her PD-related peritonitis, vancomycin was successfully reintroduced in a 50% reduced dose. No symptoms of VFR developed, and the corresponding vancomycin plasma concentration was 33.6 mg/L. Intraperitoneal treatment was continued with 500 mg vancomycin every 2-3 days with frequently measured, adequate trough levels ranging from 15-22 mg/L. This case illustrates the risk factors for the development of VFR after intraperitoneal administration of vancomycin, namely a high and concentrated loading dose together with a low body weight, a fast peritoneal transport state and peritonitis. Reintroduction of vancomycin after occurrence of VFR is safe, but a lower loading dose or a slower instillation rate is recommended.

Pharmacokinetic analysis of ceftazidime and cefazolin in the treatment of continuous ambulatory peritoneal dialysis-related peritonitis

OBJECTIVE

Peritoneal dialysis-related peritonitis (PDRP) presents a significant challenge for nephrologists. Continuous intraperitoneal cefazolin and ceftazidime are recommended for the treatment of peritonitis. However, some pharmacokinetic studies have shown that doses of 15-20 mg/kg/d may not achieve sufficient therapeutic levels. In this study, we investigated the pharmacokinetics of ceftazidime and cefazolin in patients with continuous ambulatory peritoneal dialysis-related peritonitis and compared the pharmacokinetic characteristics between traditional and modified treatment groups.

METHODS

From February 2017 to December 2019, 42 PDRP patients (17 males, 25 females; mean age: 50.7 ± 12.1 years; mean body weight: 60.9 ± 11.8 kg) were recruited for the study, all participants were anuric. Twenty patients were enrolled in the traditional group and treated with cefazolin (1.0 g) and ceftazidime (1.0 g) via intraperitoneal administration once daily for 14 days. Twenty-two patients were enrolled in the modified group and received the same dose of antibiotics twice daily for the initial five days, followed by once daily for the subsequent nine days. Serum and dialysate samples were collected after days 1, 2, 3, 5, 7, 10, and 14 and analyzed via liquid chromatography-mass spectrometry.

RESULTS

In the traditional group, the highest and lowest serum concentrations of ceftazidime were 35.9 and 21.7 µg/mL, respectively. The highest concentration of cefazolin was 54.6 µg/mL on day 5 and the lowest concentration was 30.4 µg/mL on day 1. In the modified group, the highest and lowest serum concentrations of ceftazidime were 102.2 and 54.8 µg/mL, respectively. The highest concentration of cefazolin was 141.7 µg/mL and the lowest concentration was 79.8 µg/mL. All antibiotic concentrations were above the minimum inhibitory concentration (MIC) level (8 µg/mL of ceftazidime and 2 µg/mL of cefazolin) throughout the treatment period. However, on day 1, the concentration of ceftazidime in the third bag of dialysate effluent from the traditional group fell below the MIC level. Despite remaining above the MIC, cefazolin concentration was consistently lower in the third bag of dialysate effluent from the traditional group throughout the treatment period.

CONCLUSIONS

Intraperitoneal administration of cefazolin and ceftazidime at a dose of 1 g twice daily for 5 days and then once daily for the rest of the treatment period ensured adequate therapeutic levels of antibiotics for treating anuric PDRP patients.

Serum vancomycin levels predict the short-term adverse outcomes of peritoneal dialysis-associated peritonitis

BACKGROUND

The role of monitoring serum vancomycin levels during treatment of peritoneal dialysis (PD)-associated peritonitis is controversial. Substantial inter-individual variability may result in suboptimal serum levels despite similar dosing of vancomycin. The published predictors of suboptimal serum vancomycin levels remain limited.

METHODS

Data were retrospectively collected from 541 patients on continuous ambulatory peritoneal dialysis between 1 January 2018 and 31 December 312019. For gram-positive cocci and culture-negative peritonitis, we adopted a vancomycin administration and monitoring protocol. Short-term adverse outcomes of PD-associated peritonitis, including transfer to haemodialysis, death, persistent infection beyond planned therapy duration and relapse, were observed. The association between trough serum vancomycin levels and short-term adverse outcomes was evaluated.

RESULTS

Intraperitoneal vancomycin was used in 61 gram-positive cocci or culture-negative peritonitis episodes in 56 patients. Fourteen episodes of short-term adverse outcomes occurred in 12 patients, whose average trough serum vancomycin levels on day 5 of treatment were significantly lower than those who didn't experience any adverse outcomes (8.4 ± 1.7 vs 12.5 ± 4.3 mg/L, p = 0.003). In gram-positive cocci or culture-negative peritonitis patients, those with higher day 5 trough serum vancomycin levels had a lower risk of short-term adverse outcomes (odds ratio: 0.6, 95% confidence interval: 0.4 to 0.9, p = 0.011). Receiver operating charecteristic curve (ROC) analyses showed that the day 5 trough serum vancomycin levels diagnostic threshold value for short-term adverse outcomes was 10.1 mg/L. After adjustments for gender, exchange volume and residual kidney function (RKF), baseline higher peritoneal transport was associated with a suboptimal (<10.1 mg/L) day 5 serum vancomycin level.

CONCLUSIONS

Serum vancomycin levels are correlated with short-term adverse outcomes of PD-associated peritonitis, and higher peritoneal solute transport status is associated with suboptimal trough serum vancomycin levels on day 5.

Dose Tailoring of Vancomycin Through Population Pharmacokinetic Modeling Among Surgical Patients in Pakistan

Background: Vancomycin is a narrow therapeutic agent, and it is necessary to optimize the dose to achieve safe therapeutic outcomes. The purpose of this study was to identify the significant covariates for vancomycin clearance and to optimize the dose among surgical patients in Pakistan. Methods: Plasma concentration data of 176 samples collected from 58 surgical patients treated with vancomycin were used in this study. A population pharmacokinetic model was developed on NONMEM^® using plasma concentration-time data. The effect of all available covariates was evaluated on the pharmacokinetic parameters of vancomycin by stepwise covariate modeling. The final model was evaluated using bootstrap, goodness-of-fit plots, and visual predictive checks. Results: The pharmacokinetics of vancomycin followed a one-compartment model with first-order elimination. The vancomycin clearance (CL) and volume of distribution (Vd) were 2.45 L/h and 22.6 l, respectively. Vancomycin CL was influenced by creatinine clearance (CRCL) and body weight of the patients; however, no covariate was significant for its effect on the volume of distribution. Dose tailoring was performed by simulating dosage regimens at a steady state based on the CRCL of the patients. The tailored doses were 400, 600, 800, and 1,000 mg for patients with a CRCL of 20, 60, 100, and 140 ml/min, respectively. Conclusion: Vancomycin CL is influenced by CRCL and body weight of the patient. This model can be helpful for the dose tailoring of vancomycin based on renal status in Pakistani patients.

Vancomycin in peritoneal dialysis: Clinical pharmacology considerations in therapy

Intraperitoneal vancomycin is the first-line therapy in the management of peritoneal dialysis (PD)-related peritonitis. However, due to the paucity of data, vancomycin dosing for peritonitis in patients on automated peritoneal dialysis (APD) is empiric and based on clinical experience rather than evidence. Studies in continuous ambulatory peritoneal dialysis (CAPD) patients have been used to provide guidelines for dosing and are often extrapolated for APD use, but it is unclear whether this is appropriate. This review summarizes the available pharmacokinetic data used to inform optimal dosing in patients on CAPD or APD. The determinants of vancomycin disposition and pharmacodynamic effects are critically summarized, knowledge gaps explored, and a vancomycin dosing algorithm in PD patients is proposed.

Vancomycin therapeutic drug monitoring and population pharmacokinetic models in special patient subpopulations

Vancomycin is a fundamental antibiotic in the management of severe Gram-positive infections. Inappropriate vancomycin dosing is associated with therapeutic failure, bacterial resistance and toxicity. Therapeutic drug monitoring (TDM) is acknowledged as an important part of the vancomycin therapy management, at least in specific patient subpopulations, but implementation in clinical practice has been difficult because there are no consensus and agglutinator documents. The aims of the present work are to present an overview of the current knowledge on vancomycin TDM and population pharmacokinetic (PPK) models relevant to specific patient subpopulations. Based on three published international guidelines (American, Japanese and Chinese) on vancomycin TDM and a bibliographic review on available PPK models for vancomycin in distinct subpopulations, an analysis of evidence was carried out and the current knowledge on this topic was summarized. The results of this work can be useful to redirect research efforts to address the detected knowledge gaps. Currently, TDM of vancomycin presents a moderate level of evidence and practical recommendations with great robustness in neonates, pediatric and patients with renal impairment. However, it is important to investigate in other subpopulations known to present altered vancomycin pharmacokinetics (eg neurosurgical, oncological and cystic fibrosis patients), where evidence is still unsufficient.

Population Pharmacokinetics of Vancomycin in Postoperative Neurosurgical Patients and the Application in Dosing Recommendation

Our previous study indicates that cerebrospinal fluid (CSF) albumin level is a determinant of CSF vancomycin concentration for postoperative neurosurgical patients. We aimed to develop an improved vancomycin population pharmacokinetic model with incorporation of more covariates, and to provide dosing guidance for clinicians. Vancomycin was administered intravenously to 20 patients with external ventricular drains after neurosurgical operation. Blood and CSF were collected and vancomycin concentrations were measured by HPLC. A separate CSF compartment was considered, and was linked to the central compartment by a first-order process (Q_CSF). The clearance of the CSF compartment (Cl_CSF) was used to characterize vancomycin elimination from CSF through external ventricular drain. Nonlinear mixed-effects modeling approach was used to develop the model. The CSF albumin level (mg/dL) was the covariate influencing Q_CSF: Q_CSF=0.0049+0.000021×(CSF albumin-279). The effect of body weight (BW, kg) was significant on central volume (V_C): V_C=27.84+0.96×(BW-69). All parameters were estimated with an acceptable precision (relative standard error: RSE% < 30.26). The performance of the final model was acceptable with our previous dataset. A simple to use dosage regimen table was created to guide clinicians with vancomycin dosing. This model incorporates variables of both CSF albumin and BW, which offers improvements to the previous pharmacokinetics model.

Vancomycin: the tale of the vanquisher and the pyrrhic victory

Vancomycin has been the antibiotic of choice in the treatment of methicillin-resistant Staphylococcus aureus infections for decades. But relatively recently, vancomycin-intermediate-susceptible S. aureus (VISA) have been reported. Phenotypically, VISA are characterized by thicker cell walls, requiring higher concentrations of vancomycin for inhibition of bacterial cell growth. Vancomycin-intermediate-susceptible S. aureus represent just the tip of the iceberg of an insidious loss of vancomycin susceptibility in staphylococci. Increasing proportions of S. aureus isolates have higher minimum inhibitory concentrations that are still within the officially susceptible range, a characteristic that is associated with treatment failure. The most important risk factor for decreased vancomycin susceptibility is in vivo selection pressure. To prevent the development of VISA, prolonged or inappropriate use of vancomycin and suboptimal vancomycin levels should be avoided. Trough serum vancomycin concentrations of 15 - 20 mg/L for intermittent dosing and plateau serum vancomycin concentrations of 20 - 25 mg/L for continuous infusions are therefore currently recommended. The widespread clinical application of these intensive dosing regimens has resulted in an increasing awareness of vancomycin-induced nephrotoxicity, which is especially relevant in patients whose renal function is already compromised. This narrow therapeutic-toxic window reinforces the use of rigorous dosing protocols. In hemodialysis, the use of a vancomycin dose calculator permits achievement of target concentrations in most patients. In peritoneal dialysis (PD), intermittent vancomycin dosing regimens often lead to low end-of-dwell concentrations. On the other hand, a continuous vancomycin dosing regimen after a loading dose offers the desired combination of high local levels without toxic systemic levels.

Effects of peritoneal dialysis on pharmacotherapy: a deductive pharmacokinetic-model approach to predict drug concentration profiles in plasma and peritoneal fluid

The aim of this study was to present a deductive compartment pharmacokinetic (PK) model to predict the concentration profiles of drugs in plasma and peritoneal fluid in peritoneal dialysis (PD) rats. PK parameters of model drugs in normal and experimentally induced acute renal failure (ARF) rats not undergoing PD were obtained inductively in a common regression manner with a two-compartment model. In PD normal and ARF rats, PK parameters relating to the transfer of drugs to the peritoneal dialysate and the progress of renal failure were deductively modified to simulate the drug concentration-time profiles in plasma and in the peritoneal fluid in PD rats. The deductively introduced modifiers were the volume of distribution in the peripheral compartment, plasma protein binding, and solvent movement factor to the peritoneal fluid. Predicted profiles of tolbutamide, propranolol and cefazolin in PD normal and ARF rats were compared with the corresponding observed data. This minimal deductive approach yielded satisfactory accuracy in the prediction of both the plasma and peritoneal fluid concentrations of tolbutamide and propranolol.

[Monitoring of intraperitoneal administration of vancomycin in patients on continuous ambulatory peritoneal dialysis]

OBJECTIVE

To validate a pharmacokinetic model of the treatments with intraperitoneal vancomycin applied to patients on continuous ambulatory peritoneal dialysis with bacterial peritonitis.

METHODS

To carry out a prospective study divided in 2 cohorts: the first one including ten patients of 56±14 years and 65±5 kg, and the second one with 10 patients (12 episodes of peritonitis) aged 52±13 years and 64±8 kg. The treatment consists of administering and retaining for 6 h in the peritoneal cavity a solution containing 2 g of vancomycin and 1 g of ceftazidime into 2 l of "dialysis solution". After the antibiotic administration, blood samples were obtained at 4, 6, 8, 10, 24, 48 and 168 h in the first cohort and at 6 and 120 h (C(VAN)(120)) in the second. The pharmacokinetic model was developed from the parameters obtained from the first cohort and was validated by the second cohort, calculating the mean error (ME) and the mean squared prediction error (MSPE) of the C(VAN)(120).

RESULTS

Vancomycin serum concentrations fell from 39.63±7.62 mcg/ml at 4h to 8.55±2.87 mcg/ml at 168 h for the first cohort, and from 37.65±6.84 mcg/ml at 6h to 10.82±2.66 mcg/ml at 120 h (C(VAN)(120)) for the second cohort. The pharmacokinetics parameters were: C1=0.006 1/h/kg and Vd:=0.52 1/kg for the first cohort, and C1=0.006 1/h/kg and Vd:=0.53 1/kg for the second. The predictive ME and MSPE of the C(VAN)(120). were 0.59 mcg/ml ([EM*100/C(VAN)(120)=5.5%) and 10.38 mcg(2)/ml(2) ([MES*100/(C(VAN)(120))(2)]) respectively.

CONCLUSION

The presented model shows an adequate exactitude and precision for the monitoring of intraperitoneal vancomycin in patients submitted to continuous ambulatory peritoneal dialysis with peritonitis.