Open Access

Pharmacokinetics and the optimal regimen for levofloxacin in critically ill patients receiving continuous hemodiafiltration

  • Takeshi Wada1Email author,
  • Masaki Kobayashi2,
  • Yuichi Ono1,
  • Asumi Mizugaki1,
  • Kenichi Katabami1,
  • Kunihiko Maekawa1,
  • Daisuke Miyamoto1,
  • Yuichiro Yanagida1,
  • Mineji Hayakawa1,
  • Atsushi Sawamura1,
  • Ken Iseki2, 3 and
  • Satoshi Gando1
Journal of Intensive Care20153:22

DOI: 10.1186/s40560-015-0089-0

Received: 10 January 2015

Accepted: 23 April 2015

Published: 8 May 2015

Abstract

The aim of this study was to establish the pharmacokinetics of levofloxacin (LVFX) and determine the optimal dose of this drug in critically ill patients receiving continuous hemodiafiltration (CHDF). The results of in vivo and in vitro studies showed the pharmacokinetics of LVFX total clearance (CLtotal) according to the creatinine clearance (CLCre), dialysate flow (QD), and ultrafiltrate flow (QF), to be as follows: CLtotal (l/h) = 0.0836 × CLCre (ml/min) + 0.013 × body weight (kg) + 0.94(QD + QF) (l/h). The optimal dose of LVFX was expressed by the following formula: 50 × CLtotal. These results demonstrate that the usual dose of LVFX (500 mg) was sufficient for the patients evaluated in this study.

Keywords

Levofloxacin Pharmacokinetics Continuous hemodiafiltration Clearance

Findings

The pharmacokinetics of levofloxacin (LVFX) total clearance (CLtotal) were determined based on the creatinine clearance (CLCre), dialysate flow (QD), and ultrafiltrate flow (QF), as follows:
$$ {\mathrm{CL}}_{\mathrm{total}}\left(\mathrm{l}/\mathrm{h}\right)=0.0836\times {\mathrm{CL}}_{\mathrm{Cre}}\left(\mathrm{ml}/ \min \right)+0.013\times \mathrm{body}\;\mathrm{weight}\left(\mathrm{kg}\right)+0.94\left({\mathrm{Q}}_{\mathrm{D}}+{\mathrm{Q}}_{\mathrm{F}}\right)\left(\mathrm{l}/\mathrm{h}\right) $$

Introduction

Critically ill patients often require continuous hemodiafiltration (CHDF) as a result of acute kidney injury induced by severe sepsis. Levofloxacin (LVFX) is widely used for treatment in these patients. However, the pharmacokinetics (PK) of LVFX during CHDF are not uniform, as CHDF is performed using various combinations of the dialysate flow (QD) and ultrafiltrate flow (QF). The aim of the present study was to estimate the PK of LVFX in patients receiving CHDF and determine the optimal dose of LVFX for this patient population.

Methods

Approval for this study was obtained from the institutional review board, − The Ethics Committee of Hokkaido University School of Medicine (011–0107). Informed consent for this study was obtained from the patients’ next of kin.

In vitro study

A CHDF circuit model (JUN-600, JUN-KEN MEDICAL Co., Tokyo, Japan) was established using a cellulose triacetate hollow fiber 1.1 m2 hemofilter (UT-1100, Nipro, Japan). The machine was primed with fresh frozen plasma (FFP), and 100 mg of LVFX were added to the circuit. The FFP flow was fixed at 150 ml/min, and the CHDF conditions were as follows: the QD was defined from 0, 1, and 2 l/h; the QF was defined from 0, 1, and 2 l/h, independent of QD. Samples were obtained from the prehemofilter and ultrafiltrates at 15, 30, 45, and 60 min after the start of CHDF. The sieving coefficient (SC) values were calculated based on the LVFX concentrations in the filtrates and prehemofilter. The levels of clearance (CL) via CHDF (CLCHDF) were obtained for the product of SC and (QD + QF) and then were plotted, respectively.

In vivo study

Four patients with acute kidney injury were administered LVFX during CHDF (ACH-Σ, Asahi Kasei Medical. Co., Tokyo, Japan). The hemofilter used in the in vivo study was a polysulfone hollow fiber 1.3 m2 hemofilter (EXCELFLO AEF-13, Asahi Kasei Medical. Co., Tokyo, Japan). Replacement fluid was connected to the post-filter blood line. The 24 h creatinine clearance values were accurately measured based on the urine and serum creatinine levels and the 24 h urine output. The LVFX dose was set at 500 mg/day for all patients. Blood samples were collected before the administration of LVFX and at 1, 2, 6, 12, and 24 hours after the start of drug administration. The concentration of LVFX was determined according to a high-performance liquid chromatography method, and a pharmacokinetic analysis was performed using a nonlinear least-squares regression program. The parameters were calculated by employing a two-compartment open model with a constant rate of infusion. The area under the concentration-time curve (AUC) was determined based on the trapezoidal rule. The optimal dose of LVFX was calculated based on the following relational expression:
$$ {\mathrm{CL}}_{\mathrm{total}}=\mathrm{dose}\;\mathrm{of}\;\mathrm{drug}/\mathrm{A}\mathrm{U}\mathrm{C} $$

Results

The CLCHDF obtained via interpolation into a simple linear regression of CLCHDF against (QD + QF) closely correlated with the experimental data (Figure 1). The PK of LVFX clearance (CLvivo) was determined based on the creatinine clearance (CLCre) and body weight (BW), according to previous study [1]. The LVFX total clearance (CLtotal) in a patient receiving CHDF was calculated as follows:
Figure 1

Pharmacokinetics of levofloxacin (LVFX) clearance (CL) during continuous hemodiafiltration. A simple linear regression analysis revealed a strong correlation between LVFX CLCHDF and QD + QF.

$$ {\mathrm{CL}}_{\mathrm{total}}\left(\mathrm{l}/\mathrm{h}\right)={\mathrm{CL}}_{\mathrm{vivo}}+{\mathrm{CL}}_{\mathrm{CHDF}} $$
The values of predictive CLtotal were calculated based on this formula. Table 1 shows the characteristics of the patients. We were unable to calculate the predictive CLtotal in patient No. 3 because the urine creatinine level was not examined in this case. The LVFX concentration-time curve is shown in Figure 2, and the pharmacokinetic parameters of LVFX are presented in Table 2. The AUC was 73.9 ± 13.8 (mg/l h).
Table 1

Characteristics of the patients

Patient

Sex

Age (years)

Diagnosis

Weight (kg)

APACHE II

The cause of AKI

The value of Cre on admission to ICU (mg/dl)

Duration of CHDF (days)

1

Male

75

Ruptured AAA

70.7

31

Hemorrhagic shock

1.32

66

2

Male

59

OHCA

88.9

42

PCAS

0.98

5

3

Male

46

Congenital heart disease

50.0

21

Major cardiac operation

0.69

45

4

Male

58

ML

58.3

41

Drug induced

2.04

38

Mean ± SE

 

59.5 ± 6.0

-

70.0 ± 8.5

33.8 ± 4.9

-

1.25 + 0.29

38.5 + 12.7

BUN (mmol/l)

24 h CL cre (ml/min)

Q D (l/h)

Q F (l/h)

Predictive CL total (l/h)

Calculated optimal dose of LVFX (mg)

42

3.4

1.0

2.0

4.0

200

43

0.9

1.0

2.0

4.0

200

40

-

1.0

2.0

-

-

32

3.4

0.5

1.5

2.9

145

39.3 ± 5.0

2.6 ± 0.8

0.86 + 0.13

1.88 + 0.13

3.6 ± 0.4

182 + 18.3

AAA abdominal aortic aneurysm, OHCA out-of-hospital cardiac arrest, ML malignant lymphoma, APACHE II Acute Physiology and Chronic Health Evaluation II score, AKI acute kidney injury, PCAS post-cardiac arrest syndrome, Cre creatinine, ICU intensive care unit, CHDF continuous hemodiafiltration, BUN blood urea nitrogen, CLcre creatinine clearance, CLtotal total clearance, QD dialysate flow, QF ultrafiltrate flow, LVFX levofloxacin, SE standard error.

Figure 2

Pharmacokinetics of the levofloxacin (LVFX) concentration-time curve during LVFX administration of 500 mg first 24 hours. Cons, concentration. SE, standard error.

Table 2

Pharmacokinetic parameters of levofloxacin in the patients receiving continuous hemodiafiltration

Patient

CL total (l/h)

t 1/2 (h)

C max (mcg/ml)

AUC [(mg/l) h]

1

4.62

13.1

5.7

108.3

2

12.3

14.4

3.0

40.8

3

6.64

28.9

4.7

75.3

4

7.01

11.4

4.4

71.3

Mean ± SE

7.63 + 1.6

16.9 + 4.0

4.5 + 0.6

73.9 + 13.8

CL total total clearance, t1/2 a half-life, C max maximum concentration, AUC area under the concentration-time curve, SE standard error.

Discussion

The ratio of AUC/minimum inhibitory concentration (MIC) is a well-known important PK and pharmacodynamics predictor of the clinical efficacy of fluoroquinolones, including LVFX. Previous studies suggest that the AUC/MIC of ≥100 (h) is required in compromised patients or those exhibiting severe Gram-negative rod or staphylococcal infection [2-4]. In addition, the MIC for 90% of tested strains against most common Gram-negative aerobic pathogens is < 0.5 (μg/ml) [5]. Therefore, we determined the target AUC to be ≥ 50 and the optimal dose of LVFX to be 50 × CLtotal. Hence, the LVFX concentrations reached higher than optimal concentrations, and infection could therefore be successfully controlled in these patients.

Three factors affect the PK during CHDF as follows: 1) pore size and protein binding fraction of the drug; 2) molecular size; 3) QD and QF in the CHDF protocol [6]. The triacetate and polysulfone membranes used in this study have large pores and do not have a capacity for drug absorption, characteristics recommended for CHDF. The molecular size of LVFX is 361 Da, which is less than that of ciprofloxacin (CPFX) (368 Da). The results of our previous study suggested that the pore size of the hemofilter does not influence the CLCHDF, likely due to the sufficiently low molecular weight of CPFX [7]. This previous study also indicated that the surface area of the hemofilter with a large amount of QD possibly affects the clearance of small solutes, such as fluoroquinolones [7]. Therefore, the current results are not applicable in cases in which the QD is large.

The limitations of this study should be addressed. First, the results of a study by Takigawara et al. [1], showing the relationship between the PK of LVFX and the CLCre, were based on patients with a normal renal function. These results are not applicable to the present study, as we included patients with more severe kidney injury. Second, the current study included a very small number of patients. Therefore, a larger, more precise clinical study is needed to confirm our results.

Abbreviations

LVFX: 

levofloxacin

CHDF: 

continuous hemodiafiltration

CLCre

creatinine clearance

QD

dialysate flow

QF

ultrafiltrate flow

CLtotal

LVFX total clearance

PK: 

Pharmacokinetics

FFP: 

fresh frozen plasma

SC: 

sieving coefficient

CLCHDF

clearance by CHDF

CL vivo

clearance in patients

BW: 

body weight

AUC: 

area under the concentration-time curve

MIC: 

minimum inhibitory concentration

CPFX: 

ciprofloxacin

Declarations

Acknowledgements

This study was supported by a Grant-in-Aid for Young Scientists (B) (2013–25861736) from the Ministry of Education, Science, Sports and Culture of Japan.

Authors’ Affiliations

(1)
Division of Acute and Critical Care Medicine, Department of Anesthesiology and Critical Care Medicine, Hokkaido University Graduate School of Medicine
(2)
Laboratory of Clinical Pharmaceutics & Therapeutics, Division of Pharmasciences, Faculty of Pharmaceutical Sciences, Hokkaido University
(3)
Department of Pharmacy, Hokkaido University Hospital

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Copyright

© Wada et al.; licensee BioMed Central. 2015

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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