Paracetamol metabolism in two ethnically different Spanish populations

Area of Science:

• Pharmacokinetics
• Drug Metabolism
• Toxicology

Background:

• Paracetamol (acetaminophen) is a widely used analgesic.
• Ethnic variations in drug metabolism can influence efficacy and toxicity.
• Understanding paracetamol metabolism in diverse populations is crucial for safe dosing.

Purpose of the Study:

• To compare the 24-hour urinary excretion of paracetamol and its metabolites in two Spanish populations.
• To investigate inter-individual variations in paracetamol conjugation and oxidation pathways.
• To assess potential differences in susceptibility to paracetamol-induced hepatotoxicity.

Main Methods:

• Single oral dose of 1.5 g paracetamol administered to volunteers.
• Urinary excretion of paracetamol and its glucuronide, sulphate, cysteine, and mercapturic acid conjugates measured.
• High-performance liquid chromatography (HPLC) used for metabolite quantification.
• Comparison between volunteers from the Basque Country and Alicante.

Main Results:

• No statistically significant differences in paracetamol or conjugate excretion between the two Spanish populations.
• An inverse relationship observed between glucuronide and sulphate conjugation, with bimodal distribution.
• Intersubject variation in conjugation pathways was minimal, unlike oxidation.
• Smokers excreted higher amounts of unchanged paracetamol.
• Urinary excretion of oxidation-derived metabolites was intermediate compared to Scottish Caucasians and West Africans.

Conclusions:

• Paracetamol metabolism is relatively consistent between the studied Spanish populations.
• Smoking status influences paracetamol excretion.
• Intermediate levels of oxidation metabolites may indicate a potential increased risk of hepatotoxicity in the Spanish population upon overdose.