Paracetamol (acetaminophen) warfarin interaction: NAPQI, the toxic metabolite of paracetamol, is an inhibitor of enzymes in the vitamin K cycle

Henk H. Thijssen; Berry A. Soute; Lily M. Vervoort; Jolanda G. Claessens

doi:10.1160/TH04-02-0109

Thrombosis and Haemostasis, Table of Contents

Thromb Haemost 2004; 92(04): 797-802
DOI: 10.1160/TH04-02-0109

Blood Coagulation, Fibrinolysis and Cellular Haemostasis

Schattauer GmbH

Paracetamol (acetaminophen) warfarin interaction: NAPQI, the toxic metabolite of paracetamol, is an inhibitor of enzymes in the vitamin K cycle

Authors

Henk H. Thijssen

¹Department of Pharmacology
Berry A. Soute

²Department of Biochemistry, University of Maastricht, Maastricht, The Netherlands
Lily M. Vervoort

¹Department of Pharmacology
Jolanda G. Claessens

³Department of Anticoagulation Center Maastricht, Maastricht, The Netherlands

Abstract

Summary

Paracetamol (acetaminophen) is generally considered to be the analgesic of choice for patients undergoing oral anticoagulant therapy. Occasionally, however, interactions have been reported with therapeutic doses of the analgesic, e.g. if the drug is taken for a longer period of time. The mechanism of this interaction is not clearly understood. We investigated the effects of paracetamol and its toxic metabolite N-acetyl-para-benzoquinoneimine (NAPQI) on in vitro vitamin K-dependent γ-carboxylase (VKD-carb) and vitamin K epoxide reductase (VKOR) activities. Paracetamol had no effect in either enzymatic reactions. NAPQI, on the other hand, appeared to interfere with VKD-carb activity via two mechanisms; 1) oxidation of the cofactor vitamin K-hydroquinone, 2) inactivation of the enzyme. The inactivation, in micromolar ranges, is not reversible and may be the result of covalent binding of NAPQI with functional amino acids. NAPQI also inhibited VKOR, but at higher concentrations. Unexpectedly, N-acetylcysteine was found to inhibit VKOR activity at concentrations that are obtained during rescue therapy of paracetamol intoxication. We conclude that, the potentiation of the oral anticoagulant effect by paracetamol is likely to result from NAPQI-induced inhibition of enzymes of the vitamin K cycle, particularly VKD-carb.

Keywords

Oral anticoagulation - paracetamol - drug interaction - vitamin K-dependent factors

Full Text

References

References
1 Hirsh J, Dalen JE, Anderson DR. et al. Oral anticoagulants: mechanism of action, clinical effectiveness, and optimal therapeutic range. Chest 2001; 119: 8S-21S.
2 Boeijinga JJ, Boerstra EE, Ris P. et al. Interaction between paracetamol and coumarin anticogulants. Lancet 1982; I: 506.
3 Hylek EM, Heiman H, Skates SJ. et al. Acetaminophen and other risk factors for excessive warfarin anticoagulation. JAMA 1998; 279: 657-62.
4 Andrews FJ. Retroperitoneal haematoma after paracetamol increased anticoagulation. Emerg Med J 2002; 19: 84-5.
5 Gebauer MG, Nyfort-Hansen K, Henschke PJ. et al. Warfarin and acetaminophen interaction. Pharmacotherapy 2003; 23: 109-12.
6 Shek KLA, Chan L-N, Nutescu E. Warfarinacetaminophen drug interaction revisisted. Pharmacotherapy 1999; 19: 1153-8.
7 Fattinger K, Frisullo R, Masche U. et al. No clinically relevant drug interaction between paracetamol and phenprocoumon based on a pharmacoepidemiological cohort study in medical patients. Eur J Clin Pharmacol 2002; 57: 863-7.
8 Kwan D, Bartle WR, Walker SE. The effects of acetaminophen on pharmacokinetics and pharmacodynamics of warfarin. J Clin Pharmacol 1999; 39: 68-75.
9 Whyte IM, Buckley NA, Reith DM. et al. Acetaminophen causes an increased international normalized ratio by reducing functional factor VII. Therap Drug Monitor 2000; 22: 742-8.
10 Shearer MJ. Vitamin K and vitamin K dependent proteins. Br J Haematol 1990; 75: 156-62.
11 Wood GM, Suttie JW. Vitamin K-dependent carboxylase. Stoichiometry of vitamin K epoxide formation, gamma-carboxyglutamyl formation, and gamma-glutamyl-³H cleavage. J Biol Chem 1988; 283: 3234-9.
12 Stanley TB, Jin D, Lin PJ. et al. The propeptides of the vitamin K-dependent proteins possess different affinities for the vitamin K-dependent carboxylase. J Biol Chem 1999; 274: 16940-4.
13 Houben RJ, Soute BA, Vermeer C. Assay of vitamin K-dependent carboxylase activity in hepatic and extrahepatic tissues. Meth Enzymol 1997; 282: 358-68.
14 Thijssen HH. Warfarin resistance. Vitamin K epoxide reductase of Scottish resistance genes is not irreversible blocked by warfarin. Biochem Pharmacol 1987; 36: 2753-7.
15 Dahlin DC, Nelson SD. Synthesis, decomposition kinetics, and preliminary toxicological studies of pure N-acetyl-p-benzoquinone imine, a proposed toxic metabolite of acetaminophen. J Med Chem 1982; 25: 885-6.
16 Bessems JGM, Vermeulen NPE. Paracetamolinduced toxicity. Molecular and biochemical mechanisms, analogues and protective approaches. Crit Rev Toxicol 2001; 31: 55-138.
17 Vale JA, Proudfoot AT. Paracetamol (acetaminophen) poisoning. The Lancet 1995; 346: 547-52.
18 Wu SM, Soute BA, Vermeer C. et al. In vitro gamma-carboxylation of a 59-residue recombinant peptide including the propeptide and the gamma-carboxyglutamic acid domain of coagulation factor IX. Effect of mutations near the propeptide cleavage site. J Biol Chem 1990; 265: 13124-9.
19 Gadisseur AP, Van der Meer FJ, Rosendaal FR. Sustained intake of paracetamol (acetaminophen) during oral anticoagulant therapy with coumarins does not cause clinically important INR changes: a randomized doubleblind clinical trial. J Thromb Haemost 2003; 01: 714-7.
20 Ronden JE, Soute BAM, Thijssen HHW. et al. Natural prenylquinones inhibit the enzymes of the vitamin K cycle in vitro. Biochim Biophys Acta 1996; 1298: 87-94.
21 Pudota BN, Miyagi M, Hallgren KW. et al. Identification of the vitamin K-dependent carboxylase active site: Cys-99 and Cys-450 are required for both epoxidation and carboxylation. Proc Natl Acad Sci USA 2000; 97: 13033-8.
22 Tie J-K, Mutucumarena VP, Straight DL. et al. Determination of disulfide bond assignment of human vitamin K-dependent “γ-glutamyl carboxylase by matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry. J Biol Chem 2003; 278: 45468-75.
23 Lee JJ, Fasco MJ. Metabolism of vitamin K and vitamin K 2,3-epoxide via interaction with a common disulfide. Biochem 1984; 23: 2246-52.
24 Bouchard BA, Furie B, Furie BC. Glutamyl substrate-induced exposure of a free cysteine residue in the vitamin K-dependent “γ-glutamyl carboxylase is critical for vitamin K epoxidation. Biochem 1999; 38: 9517-23.
25 Dowd P, Zheng ZB. On the mechanism of the anticlotting action of vitamin E quinone. Proc Natl Acad Sci USA 1995; 92: 8171-5.
26 Loguerco C, Taranto D, Vitale LM. et al. Effect of liver cirrhosis and age on the glutathione concentration in the plasma, erythrocytes, and gastric mucosa of man. Free Rad Biol Med 1996; 20: 483-8.
27 Enomoto A, Itoh K, Nagayoshi E. et al. High sensitivity of Nrf2 knockout mice to acetaminophen hepatotoxicity associated with decreased expression of ARE-regulated drug metabolizing enzymes and antioxidant genes. Toxicol Sci 2001; 59: 169-77.
28 Schmidt LE, Knudsen TT, Dalhoff K. et al. Effect of acetylcysteine on prothrombin index in paracetamol poisoning without hepatocellular injury. Lancet 2002; 360: 1151-2.
29 Prescott LF, Donovan JW, Jarvie DR. et al. The disposition and kinetics of intravenous Nacetylcysteine in patients with paracetamol overdosage. Eur J Clin Pharmacol 1989; 37: 501-6.