Effects of intravenous paracetamol in obese and non-obese patients

Pharmacokinetics and Pharmacodynamics of Intravenous Paracetamol/Acetaminophen in Morbidly Obese and Non- Obese Patients.

Observational University Hospital, Ghent · NCT06549062

This study is trying to see how intravenous paracetamol works in morbidly obese patients compared to non-obese individuals to help figure out the right dosage for both groups.

Quick facts

Study typeObservational
Enrollment70 (estimated)
Ages18 Years to 70 Years
SexAll
SponsorUniversity Hospital, Ghent Academic / other
Locations1 site (Ghent, Oost-Vlaanderen)
Trial IDNCT06549062 on ClinicalTrials.gov

What this trial studies

This observational study investigates the pharmacokinetics and pharmacodynamics of intravenous paracetamol in morbidly obese patients compared to non-obese individuals. It aims to validate a prediction model for plasma concentrations of paracetamol and its metabolites over a 30-hour period, while also comparing venous blood results with those obtained from volumetric absorptive microsampling (VAMS) after a finger stick. The hypothesis is that morbidly obese patients may require higher doses of paracetamol due to increased CYP2E1-mediated oxidation, which could lead to higher levels of the toxic metabolite NAPQI. The findings could inform future dosing recommendations for paracetamol in obese patients.

Who should consider this trial

Good fit: Ideal candidates include adults aged 18 to 70, both morbidly obese scheduled for laparoscopic bariatric surgery and non-obese individuals scheduled for laparoscopic surgery.

Not a fit: Patients with documented liver disease, kidney disease, or those who are pregnant may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved dosing guidelines for paracetamol in morbidly obese patients, enhancing pain management and reducing the risk of hepatotoxicity.

How similar studies have performed: While there have been studies on paracetamol dosing in obese patients, this specific approach of validating a prediction model and using VAMS for sampling is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Adult ≥ 18 \< 70 years old (obese patients) Adult ≥ 18 years old (non-obese patients)
2. Able to comprehend, sign, and date the written informed consent document to participate in the clinical trial
3. Obese scheduled for laparoscopic bariatric surgery Non obese scheduled for laparoscopic surgery
4. Control group BMI ≥18.5 en \<30 kg.m-2 or Obese group BMI \> 35kg.m-2
5. ASA Class I, II or III as assigned by the anaesthesiologist

Exclusion Criteria:

1. Allergy or inability to tolerate "paracetamol"
2. Documented Liver disease or liver enzymes \> 3X normal value
3. Kidney disease (eGFR \< 30ml.min-1)
4. Participation in a clinical trial within the past 30 days
5. Chronic alcohol abuse or alcohol intake \<72hrs
6. Gilbert-Meulengracht-syndroom
7. Chronic malnutrition
8. Intake of medication with influence on CYP2E1 or UDP-glucuronosyltransferase
9. Pregnancy

Where this trial is running

Ghent, Oost-Vlaanderen

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Acetaminophen ToxicityObesity, Morbidacetaminophen pharmacokineticsobesityNAPQI protein adductsCYP 2E1
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.