Inhibition of paracetamol glucuronidation by tyrosine kinase inhibitors

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: • Clinical cases reported that fatal acute liver failure occurred when paracetamol (acetaminophen) was co-administrated with some tyrosine kinase inhibitors (TKIs). The direct inhibition of UDP-glucuronosyltransferase activities has been identified as a mechanism of potentiation of paracetamol hepatotoxicity. However, the effects of TKIs on paracetamol glucuronidation are not known. WHAT THIS STUDY ADDS: • The TKIs, sorafenib, dasatinib and imatinib exhibited potent mixed inhibition against paracetamol glucuronidation in pooled human liver microsomes, implying a possible increase in paracetamol hepatotoxicity when they are co-administrated with paracetamol. AIMS We aimed to investigate the effects of tyrosine kinase inhibitors (TKIs) on paracetamol (acetaminophen) glucuronidation. METHODS: The inhibition of nine small molecule TKIs on paracetamol glucuronidation was investigated in human liver microsomes (HLMs) and recombinant human UDP-glucuronosyltransferases (UGTs). RESULTS: Sorafenib, dasatinib and imatinib exhibited mixed inhibition against paracetamol glucuronidation in pooled HLMs, and potent inhibition in UGT1A9 and UGT2B15. Dasatinib and imatinib also inhibited UGT1A1-mediated paracetamol glucuronidation. Axitinib, erlotinib, gefitinib, lapatinib, nilotinib and vandetanib exhibited weak inhibition of paracetamol glucuronidation activity in HLMs. CONCLUSIONS: The inhibition of paracetamol glucuronidation by TKIs might be of particular concern when they are co-administered.