Effects of Paracetamol on NOS, COX, and CYP Activity and on Oxidative Stress in Healthy Male Subjects, Rat Hepatocytes, and Recombinant NOS

• Published in: Oxidative medicine and cellular longevity Vol. 2014; no. 2014; pp. 1 - 12
• Main Authors: Tsikas, Dimitrios, Stichtenoth, Dirk O., Staerk, Ulrich, Probst, Irmelin, Suchy, Maria-Theresia, Böhmer, Anke, Trettin, Arne, Frölich, Jürgen C.
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Publishing Corporation 01.01.2014; John Wiley & Sons, Inc
• Subjects: Acetaminophen; Acetaminophen - pharmacology; Adult; Animals; Cytochrome P-450 Enzyme System - metabolism; Drug metabolism; Enzymes; Epoprostenol - biosynthesis; Genetic aspects; Hepatocytes - drug effects; Hepatocytes - enzymology; Humans; Male; Middle Aged; Nitric Oxide - metabolism; Nitric Oxide Synthase - genetics; Nitric Oxide Synthase - metabolism; Nitric Oxide Synthase - pharmacology; Nitric Oxide Synthase Type II - genetics; Nitric Oxide Synthase Type II - metabolism; Nitric Oxide Synthase Type II - pharmacology; Nitric Oxide Synthase Type III - genetics; Nitric Oxide Synthase Type III - metabolism; Nitric Oxide Synthase Type III - pharmacology; Oxidative stress; Oxidative Stress - drug effects; Patient outcomes; Prostaglandin-Endoperoxide Synthases - metabolism; Rats; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Recombinant Proteins - pharmacology; Regulation; Thromboxanes - biosynthesis
• DOI: 10.1155/2014/212576
• ISSN: 1942-0900; 1942-0994

Paracetamol (acetaminophen) is a widely used analgesic drug. It interacts with various enzyme families including cytochrome P450 (CYP), cyclooxygenase (COX), and nitric oxide synthase (NOS), and this interplay may produce reactive oxygen species (ROS). We investigated the effects of paracetamol on prostacyclin, thromboxane, nitric oxide (NO), and oxidative stress in four male subjects who received a single 3 g oral dose of paracetamol. Thromboxane and prostacyclin synthesis was assessed by measuring their major urinary metabolites 2,3-dinor-thromboxane B2 and 2,3-dinor-6-ketoprostaglandin F1α, respectively. Endothelial NO synthesis was assessed by measuring nitrite in plasma. Urinary 15(S)-8-iso-prostaglanding F2α was measured to assess oxidative stress. Plasma oleic acid oxide (cis-EpOA) was measured as a marker of cytochrome P450 activity. Upon paracetamol administration, prostacyclin synthesis was strongly inhibited, while NO synthesis increased and thromboxane synthesis remained almost unchanged. Paracetamol may shift the COX-dependent vasodilatation/vasoconstriction balance at the cost of vasodilatation. This effect may be antagonized by increasing endothelial NO synthesis. High-dosed paracetamol did not increase oxidative stress. At pharmacologically relevant concentrations, paracetamol did not affect NO synthesis/bioavailability by recombinant human endothelial NOS or inducible NOS in rat hepatocytes. We conclude that paracetamol does not increase oxidative stress in humans.