Paracetamol (PCM) is extensively metabolized in the liver via glucuronidation, sulfation, and oxidation. Although oral and intravenous PCM are commonly used interchangeably, a comprehensive evaluation of PCM metabolism across both routes is lacking. This study aimed to characterize the full pharmacokinetic (PK) profiles of PCM and its metabolites following oral and intravenous administration, accounting for presystemic and systemic metabolism. Concentrations of PCM, PCM-glucuronide (PCM-GLU), PC