For example, systemic exposure to sorafenib, a tyrosine kinase inhibitor used for the treatment of advanced renal cell carcinoma, and its metabolite N-oxide sorafenib increased in the presence of acetaminophen in rats [26], which may be due to P-glycoprotein (P-gp) inhibition by acetaminophen [27]. The gene discussed is PGP; the disease is renal cell carcinoma.