TABLE 1

Examples of cofactors, substrates, inhibitors, and primary tissue locations for P450 and UGT drug-metabolizing enzymes

EnzymeCofactorSubstrateInhibitorTissue Location
CYP1A2NADPHPhenacetin, caffeineα-Naphthoflavone, furafyllineaLiver
CYP2A6NADPHCoumarinLiver, lung
CYP2B6NADPHBupropion, efavirenzClotrimazoleLiver, lung
CYP2C8NADPHMontelukast, paclitaxel, amodiaquineQuercetin, montelukast, gemfibrozil glucuronideaLiver
CYP2C9NADPH(S)-Warfarin, diclofenac, tolbutamideSulfaphenazole, tienilic acidaLiver
CYP2C19NADPH(S)-Mephenytoin, (±)-omeprazole(+)-N-3-BenzylnirvanolLiver
CYP2D6NADPHDextromethorphan, (±)-bufuralolQuinidine, paroxetineaLiver
CYP2E1NADPHChlorzoxazoneDiethyldithiocarbamateLiver, lung
CYP2J2NADPHArachidonic acid, terfenadine, astemizoleKetoconazoleLung
CYP3A4/5NADPHMidazolam, testosterone, nifedipineKetoconazole, mibefradil,a mifepristone,a troleandomycinLiver, small intestine (3A4), lung (3A5)
UGT1A1UDPGABilirubin, estradiol, ethynylestradiolAtazanavir, indinavir, ketoconazole, flavonesLiver, intestine
UGT1A3UDPGAF6-1α,23S,25-trihydroxyvitamin-D3, lithocholic acid, fulvestrantBuprenorphine, amitriptyline, temazepamLiver
UGT1A4UDPGATrifluoperazine, imipramineHecogenin, lamotrigineLiver, stomach
UGT1A6UDPGASerotoninBisphenol A, troglitazone, rose bengalLiver, brain
UGT1A7UDPGABenzo[α]pyrene metabolitesPhenylbutazone, quinidineEsophagus, stomach
UGT1A8UDPGABenzo[α]pyrene metabolites, dihydrotestosterone diglucuronideEmodinEsophagus, intestine
UGT1A9UDPGAPropofol, entacaponeNiflumic acid, diflunisal, ketoconazoleKidney, liver
UGT1A10UDPGADopamineTacrolimusKidney, intestine, lung
UGT2B4UDPGAHyodeoxycholic acidDiclofenac, laropiprantLiver
UGT2B7UDPGAAzidothymidine, morphine, codeineDiclofenac, flurbiprofen, mefanemic acidLiver, intestine, kidney
UGT2B10UDPGANicotineUnknownLiver, prostate, breast
UGT2B15UDPGA(S)-OxazepamValproic acid, diclofenacLiver, prostate
UGT2B17UDPGADihydrotestosteroneDiclofenac, ibuprofenLiver, prostate
  • UDPGA, UDP glucuronic acid.

  • a Denotes time-dependent inhibitor.