Exploring the opportunity for therapeutic drug monitoring (TDM) and precision dose antimicrobials in an outpatient antimicrobial therapy (OPAT) service: a prospective observational study
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Published version
OA Location
Author(s)
Type
Journal Article
Abstract
Objectives
Notwithstanding the wide uptake of outpatient antimicrobial therapy (OPAT) in the UK, there is a paucity of data on antimicrobial exposure. We aimed to assess antimicrobial pharmacokinetic–pharmacodynamics (PK–PD) for several agents in our service with a view to understanding a potential role for therapeutic drug monitoring (TDM) and precision antimicrobial therapy in this setting.
Methods
The study was a prospective, observational, pilot PK–PD study. Adult patients receiving intravenous ceftazidime, ceftriaxone, daptomycin, ertapenem, flucloxacillin or teicoplanin, or oral treatment with linezolid were enrolled. Peak and trough blood samples were obtained. Total and unbound antibacterial concentrations were measured. Clinical details, laboratory findings and UK OPAT good practice recommendation metrics were extracted from the medical record. PK–PD was interpreted according to EUCAST rationale documents and other published guidance. Doses were not adjusted except for linezolid and teicoplanin.
Results
In total, 39 patients were recruited to the study, predominantly on ceftriaxone (21/39, 54%) or ertapenem (6/39, 15%). Four patients received (10%) teicoplanin, three (8%) ceftazidime, three (8%) flucloxacillin, one (3%) linezolid and one (3%) daptomycin. The most common reason for OPAT was bacteraemia and endocarditis (6/39; 15% each). PK–PD target attainment was acceptable for all drugs and dose regimens, and all β-lactam-based treatments met conservative PK–PD targets.
Conclusions
We have demonstrated that drug monitoring is practicable in the OPAT setting of a large institution with no on-site analytical capability. Current dosage regimens result in acceptable PK–PD target attainment. Our findings provide an initial step towards supporting TDM in OPAT.
Notwithstanding the wide uptake of outpatient antimicrobial therapy (OPAT) in the UK, there is a paucity of data on antimicrobial exposure. We aimed to assess antimicrobial pharmacokinetic–pharmacodynamics (PK–PD) for several agents in our service with a view to understanding a potential role for therapeutic drug monitoring (TDM) and precision antimicrobial therapy in this setting.
Methods
The study was a prospective, observational, pilot PK–PD study. Adult patients receiving intravenous ceftazidime, ceftriaxone, daptomycin, ertapenem, flucloxacillin or teicoplanin, or oral treatment with linezolid were enrolled. Peak and trough blood samples were obtained. Total and unbound antibacterial concentrations were measured. Clinical details, laboratory findings and UK OPAT good practice recommendation metrics were extracted from the medical record. PK–PD was interpreted according to EUCAST rationale documents and other published guidance. Doses were not adjusted except for linezolid and teicoplanin.
Results
In total, 39 patients were recruited to the study, predominantly on ceftriaxone (21/39, 54%) or ertapenem (6/39, 15%). Four patients received (10%) teicoplanin, three (8%) ceftazidime, three (8%) flucloxacillin, one (3%) linezolid and one (3%) daptomycin. The most common reason for OPAT was bacteraemia and endocarditis (6/39; 15% each). PK–PD target attainment was acceptable for all drugs and dose regimens, and all β-lactam-based treatments met conservative PK–PD targets.
Conclusions
We have demonstrated that drug monitoring is practicable in the OPAT setting of a large institution with no on-site analytical capability. Current dosage regimens result in acceptable PK–PD target attainment. Our findings provide an initial step towards supporting TDM in OPAT.
Date Issued
2026-02-01
Date Acceptance
2025-12-13
Citation
Journal of Antimicrobial Chemotherapy, 2026, 81 (2)
ISSN
0305-7453
Publisher
Oxford University Press
Journal / Book Title
Journal of Antimicrobial Chemotherapy
Volume
81
Issue
2
Copyright Statement
© The Author(s) 2026. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/ by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/41609506
PII: 8444604
Subjects
Humans
Drug Monitoring
Prospective Studies
Male
Middle Aged
Female
Aged
Anti-Bacterial Agents
Adult
Pilot Projects
Outpatients
United Kingdom
Aged, 80 and over
Ambulatory Care
Bacterial Infections
Young Adult
Publication Status
Published
Coverage Spatial
England
Article Number
dkaf484
Date Publish Online
2026-01-29