- Design
- Single-centre retrospective analysis of therapeutic drug monitoring
- Population
- 62 posaconazole levels from 30 children in a paediatric ICU, 2010–2025
- Primary outcome
- Proportion of levels below therapeutic target
- Effect
- 39% subtherapeutic; liquid formulation OR 29.6 (2.2–398.2); 28% low on IV
A single-centre retrospective study in Clinical and Translational Science (1 September) reviewed 15 years of posaconazole therapeutic drug monitoring in a paediatric intensive care unit: 62 levels from 30 children, against targets of 1.0 mg/L for treatment and 0.7 mg/L for prophylaxis.
Thirty-nine per cent of levels were below target. The liquid formulation was strongly associated with low levels (odds ratio 29.6, 95% CI 2.2 to 398), but even with intravenous dosing 28% of levels were subtherapeutic.
The mechanism is familiar: oral suspension absorption depends on food and gastric conditions that critical illness disrupts, and altered volume of distribution and clearance affect all routes. The study is small and the confidence interval for the formulation effect is very wide, but the practical point is robust — posaconazole dosing in sick children cannot be assumed adequate from the label dose. Measure a trough, and prefer tablets or intravenous dosing over suspension where possible.
- Check a posaconazole trough level in every critically ill child on the drug.
- Avoid the oral suspension in critically ill children where tablets or intravenous dosing are feasible.
- Do not assume intravenous dosing guarantees target levels; 28% were still low.
- Recheck levels after changes in formulation, feeding or interacting drugs.
Why it matters
Subtherapeutic antifungal exposure in the sickest children goes unnoticed without monitoring.
Don't overread it
Small single-centre retrospective data; it shows exposure, not whether low levels caused treatment failure.
The statistics, in plain English
An odds ratio of 29.6 with an interval from 2.2 to 398 means the suspension was clearly linked to low levels, but the true size of the effect is very uncertain because the study was small. The 39% figure is per level measured, not per child.
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