Identification of human liver cytochrome P-450 3A4 as the enzyme responsible for fentanyl and sufentanil N-dealkylation.
Alfentanil, sufentanil, and fentanyl are synthetic opioids that are metabolized by oxidative N-dealkylation in the liver. We have previously shown that cytochrome P-450 3A4 (CYP3A4) contributes significantly to human liver microsomal alfentanil oxidation. Since identification of specific drug-metabolizing enzymes allows prediction of the variables affecting drug metabolism, the purpose of the present study was to identify the P-450 enzymes responsible for sufentanil and fentanyl metabolism in human liver microsomes. Microsomal preparations fortified with a reduced nicotinamide-adenine dinucleotide phosphate-generating system were incubated with 0.25 microM 3H-fentanyl or 3H-sufentanil. Rates of N-dealkylated metabolite formation significantly correlated with nifedipine oxidation activity (a marker of CYP3A4 activity) for fentanyl and sufentanil (r = 0.93 and 0.87, n = 18, respectively), but not with the oxidation activity for ethoxyresorufin (CYP1A2), S-mephenytoin (CYP2C19), bufuralol (CYP2D6), or chlorzoxazone (CYP2E1). Gestodene and troleandomycin (chemical inhibitors of CYP3A4) and antibody to CYP3A4 inhibited N-dealkylation of fentanyl and sufentanil. Chemical inhibitors of CYP2C, 2E1, and 2D6 did not inhibit N-dealkylation of fentanyl and sufentanil. Recombinant CYP3A4 expressed in Escherichia coli showed N-dealkylation activity of fentanyl and sufentanil, while expressed CYP1A2, 2C10, and 2E1 enzymes did not. We conclude that CYP3A4 is responsible for fentanyl and sufentanil N-dealkylation in vitro.
Tateishi
T
T
Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2125, USA.
Krivoruk
Y
Y
Ueng
Y F
YF
Wood
A J
AJ
Guengerich
F P
FP
Wood
M
M
D000701:Analgesics, Opioid / Q000378:metabolism*; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D000918:Antibody Specificity; D051544:Cytochrome P-450 CYP3A; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000276:immunology / Q000378:metabolism*; D003640:Dealkylation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004917:Erythromycin / Q000494:pharmacology; D005283:Fentanyl / Q000031:analogs & derivatives / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008862:Microsomes, Liver / Q000201:enzymology; D006899:Mixed Function Oxygenases / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D009652:Norpregnenes / Q000494:pharmacology; D011817:Rabbits; D017409:Sufentanil / Q000031:analogs & derivatives / Q000378:metabolism*; D014217:Troleandomycin / Q000494:pharmacology
D000701:Analgesics, Opioid; D000906:Antibodies; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D009652:Norpregnenes; C097508:norsufentanil; C033273:Gestodene; C080127:norfentanyl; D004917:Erythromycin; D003577:Cytochrome P-450 Enzyme System; D017409:Sufentanil; D014217:Troleandomycin; D006899:Mixed Function Oxygenases; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; D005283:Fentanyl