A pharmacokinetic study of intravenous paracetamol in patients after cardiac surgery

Intravenous (iv) paracetamol is increasingly used as an adjunct analgesic to
limit the perioperative use of opioids, although the results of studies
addressing this issue show ambiguous results. It may well be that insufficient
paracetamol concentrations obtained after the standard infusion regimen (1 gram
given over 20 min) may be responsible for this. It is generally assumed that
effective concentrations are between 10-20 mg/l. In-house TDM data suggest that
the paracetamol concentration drops below the presumably effective range after
approximately 2 hours. Therefore a study is proposed to prospectively validate
the theoretical infusion regimen.

The objective of the study is to investigate the plasma concentrations of
paracetamol after an iv infusion using a model-derived infusion schedule.

Open PK study

IV paracetamol as continuous IV infusion (routine practice is IV bolus
administration)

As the only change compared to routine clinical practice is the duration of the
infusion of paracetamol and the study requires a total amount of ~65 ml blood
to be taken, the burden and the risks associated with participation in this
study is considered to be minimal (or even negligible)