Therapeutic Drug Monitoring of Amphotericin-B in Plasma and Peritoneal Fluid of Pediatric Patients after Liver Transplantation: A Case Series

Therapeutic drug monitoring of liposomal amphotericin B in children. Are we there yet? A systematic review

INTRODUCTION

Therapeutic drug monitoring (TDM) is a tool that supports personalized dosing, but its role for liposomal amphotericin B (L-amb) is unclear. This systematic review assessed the evidence for L-amb TDM in children.

OBJECTIVES

To evaluate the concentration-efficacy relationship, concentration-toxicity relationship and pharmacokinetic/pharmacodynamic (PK/PD) variability of L-amb in children.

METHODS

We systematically reviewed PubMed and Embase databases following PRISMA guidelines. Eligible studies included L-amb PK/PD studies in children aged 0-18 years. Review articles, case series of

RESULTS

In total, 4220 studies were screened; 6 were included, presenting data on 195 children. Invasive candidiasis and aspergillosis were the two most common infections treated with L-amb. Studies showed significant PK variability due to age (mean age ranged from 14 days to 17 years), body weight, non-linear PK and changes in the volume of distribution. Limited evidence supported a peak concentration/MIC (Cmax/MIC) of 25-50 for optimal efficacy and an AUC24 of >600 mg·h/L for nephrotoxicity. L-amb doses of 2.5-10 mg/kg/day were reported to achieve Cmax/MIC > 25 using an MIC of 1 mg/L.

CONCLUSIONS

While significant PK variability was observed in children, evidence to support routine L-amb TDM was limited. Further studies on efficacy and toxicity benefits are required before routine TDM of L-amb can be recommended.

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MESH Headings

• Child
• Animals
• Humans
• Infant, Newborn
• Antifungal Agents/adverse effects
• Drug Monitoring
• Amphotericin B/adverse effects
• Candidiasis, Invasive/drug therapy

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Grants

• Australian Government (RTP) Scholarship

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Affiliation(s)

Tony Lai Pharmacy Department, The Children’s Hospital at Westmead, Sydney, NSW, Australia The University of Sydney Infectious Diseases Institute (Sydney ID), Sydney, NSW, Australia Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
Chin-Yen Yeo Pharmacy Department, Concord Hospital, Sydney, Australia
Bradley Rockliff Pharmacy Department, The Children’s Hospital at Westmead, Sydney, NSW, Australia
Michael Stokes Pharmacy Department, The Children’s Hospital at Westmead, Sydney, NSW, Australia The University of Sydney Infectious Diseases Institute (Sydney ID), Sydney, NSW, Australia
Hannah Yejin Kim Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia Pharmacy Department, Westmead Hospital, Sydney, Australia
Ben J Marais The University of Sydney Infectious Diseases Institute (Sydney ID), Sydney, NSW, Australia
Andrew J McLachlan Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
Jan-Willem C Alffenaar The University of Sydney Infectious Diseases Institute (Sydney ID), Sydney, NSW, Australia Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia Pharmacy Department, Westmead Hospital, Sydney, Australia

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Pharmacokinetic and pharmacodynamic considerations for antifungal therapy optimisation in the treatment of intra-abdominal candidiasis

Intra-abdominal candidiasis (IAC) is one of the most common of invasive candidiasis observed in critically ill patients. It is associated with high mortality, with up to 50% of deaths attributable to delays in source control and/or the introduction of antifungal therapy. Currently, there is no comprehensive guidance on optimising antifungal dosing in the treatment of IAC among the critically ill. However, this form of abdominal sepsis presents specific pharmacokinetic (PK) alterations and pharmacodynamic (PD) challenges that risk suboptimal antifungal exposure at the site of infection in critically ill patients. This review aims to describe the peculiarities of IAC from both PK and PD perspectives, advocating an individualized approach to antifungal dosing. Additionally, all current PK/PD studies relating to IAC are reviewed in terms of strength and limitations, so that core elements for the basis of future research can be provided.

Critical appraisal beyond clinical guidelines for intraabdominal candidiasis

BACKGROUND

Regardless of the available antifungals, intraabdominal candidiasis (IAC) mortality continues to be high and represents a challenge for clinicians.

MAIN BODY

This opinion paper discusses alternative antifungal options for treating IAC. This clinical entity should be addressed separately from candidemia due to the peculiarity of the required penetration of antifungals into the peritoneal cavity. Intraabdominal concentrations may be further restricted in critically ill patients where pathophysiological facts alter normal drug distribution. Echinocandins are recommended as first-line treatment in guidelines for invasive candidiasis. However, considering published data, our pharmacodynamic analysis suggests the required increase of doses, postulated by some authors, to attain adequate pharmacokinetic (PK) levels in peritoneal fluid. Given the limited evidence in the literature on PK/PD-based treatments of IAC, an algorithm is proposed to guide antifungal treatment. Liposomal amphotericin B is advocated as first-line therapy in patients with sepsis/septic shock presenting candidemia or endophthalmitis, or with prior exposure to echinocandins and/or fluconazole, or with infections by Candida glabrata. Other situations and alternatives, such as new compounds or combination therapy, are also analysed.

CONCLUSION

There is a critical need for more robust clinical trials, studies examining patient heterogeneity and surveillance of antifungal resistance to enhance patient care and optimise treatment outcomes. Such evidence will help refine the existing guidelines and contribute to a more personalised and effective approach to treating this serious medical condition. Meanwhile, it is suggested to broaden the consideration of other options, such as liposomal amphotericin B, as first-line treatment until the results of the fungogram are available and antifungal stewardship could be implemented to prevent the development of resistance.