Details of Drug Interaction | MecDDI

Drug General Information (ID: DDIGUYNX27)
Drug Name			Eletriptan		Drug Info		Mifepristone		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antimigraine Agents				Uterotonic Agents
Structure

Mechanism of Eletriptan-Mifepristone Interaction (Severity Level: Major)
CYP450 enzyme inhibition Click to Show/Hide Mechanism Graph

Drug Name		Eletriptan				Mifepristone
Mechanism		CYP450 3A4 substrate				CYP450 3A4 inhibitor
Key Mechanism Factor 1
		Factor Name		Cytochrome P450 3A4				× Structure Sequence MALIPDLAMETWLLLAVSLVLLYLYGTHSHGLFKKLGIPGPTPLPFLGNILSYHKGFCMFDMECHKKYGKVWGFYDGQQPVLAITDPDMIKTVLVKECYSVFTNRRPFGPVGFMKSAISIAEDEEWKRLRSLLSPTFTSGKLKEMVPIIAQYGDVLVRNLRREAETGKPVTLKDVFGAYSMDVITSTSFGVNIDSLNNPQDPFVENTKKLLRFDFLDPFFLSITVFPFLIPILEVLNICVFPREVTNFLRKSVKRMKESRLEDTQKHRVDFLQLMIDSQNSKETESHKALSDLELVAQSIIFIFAGYETTSSVLSFIMYELATHPDVQQKLQEEIDAVLPNKAPPTYDTVLQMEYLDMVVNETLRLFPIAMRLERVCKKDVEINGMFIPKGVVVMIPSYALHRDPKYWTEPEKFLPERFSKKNKDNIDPYIYTPFGSGPRNCIGMRFALMNMKLALIRVLQNFSFKPCKETQIPLKLSLGGLLQPEKPVVLKVESRDGTVSGA
		Gene Name		CYP3A4
		Uniprot ID		CP3A4_HUMAN
		KEGG Pathway		hsa:1576
		Protein Family		Cytochrome P450 family
		Protein Function		A cytochrome P450 monooxygenase involved in the metabolism of sterols, steroid hormones, retinoids and fatty acids (PubMed:10681376, PubMed:11093772, PubMed:11555828, PubMed:14559847, PubMed:12865317, PubMed:15373842, PubMed:15764715, PubMed:20702771, PubMed:19965576, PubMed:21490593, PubMed:21576599). Mechanistically, uses molecular oxygen inserting one oxygen atom into a substrate, and reducing the second into a water molecule, with two electrons provided by NADPH via cytochrome P450 reductase (NADPH--hemoprotein reductase). Catalyzes the hydroxylation of carbon-hydrogen bonds (PubMed:2732228, PubMed:14559847, PubMed:12865317, PubMed:15373842, PubMed:15764715, PubMed:21576599, PubMed:21490593). Exhibits high catalytic activity for the formation of hydroxyestrogens from estrone (E1) and 17beta-estradiol (E2), namely 2-hydroxy E1 and E2, as well as D-ring hydroxylated E1 and E2 at the C-16 position (PubMed:11555828, PubMed:14559847, PubMed:12865317). Plays a role in the metabolism of androgens, particularly in oxidative deactivation of testosterone (PubMed:2732228, PubMed:15373842, PubMed:15764715, PubMed:22773874). Metabolizes testosterone to less biologically active 2beta- and 6beta-hydroxytestosterones (PubMed:2732228, PubMed:15373842, PubMed:15764715). Contributes to the formation of hydroxycholesterols (oxysterols), particularly A-ring hydroxylated cholesterol at the C-4beta position, and side chain hydroxylated cholesterol at the C-25 position, likely contributing to cholesterol degradation and bile acid biosynthesis (PubMed:21576599). Catalyzes bisallylic hydroxylation of polyunsaturated fatty acids (PUFA) (PubMed:9435160). Catalyzes the epoxidation of double bonds of PUFA with a preference for the last double bond (PubMed:19965576). Metabolizes endocannabinoid arachidonoylethanolamide (anandamide) to 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acid ethanolamides (EpETrE-EAs), potentially modulating endocannabinoid system signaling (PubMed:20702771). Plays a role in the metabolism of retinoids. Displays high catalytic activity for oxidation of all-trans-retinol to all-trans-retinal, a rate-limiting step for the biosynthesis of all-trans-retinoic acid (atRA) (PubMed:10681376). Further metabolizes atRA toward 4-hydroxyretinoate and may play a role in hepatic atRA clearance (PubMed:11093772). Responsible for oxidative metabolism of xenobiotics. Acts as a 2-exo-monooxygenase for plant lipid 1,8-cineole (eucalyptol) (PubMed:11159812). Metabolizes the majority of the administered drugs. Catalyzes sulfoxidation of the anthelmintics albendazole and fenbendazole (PubMed:10759686). Hydroxylates antimalarial drug quinine (PubMed:8968357). Acts as a 1,4-cineole 2-exo-monooxygenase (PubMed:11695850). Also involved in vitamin D catabolism and calcium homeostasis. Catalyzes the inactivation of the active hormone calcitriol (1-alpha,25-dihydroxyvitamin D(3)) (PubMed:29461981). Click to Show/Hide
Mechanism Description		Decreased metabolism of Eletriptan caused by Mifepristone mediated inhibition of CYP450 enzyme

Recommended Action
Management		When mifepristone is used daily to control hyperglycemia secondary to hypercortisolism in patients with endogenous Cushing's syndrome, concomitant use of CYP450 3A4 substrates with narrow therapeutic ranges and high first-pass effect is considered contraindicated. These drugs include lovastatin, simvastatin, cyclosporine, ergot derivatives, fentanyl, oral midazolam, triazolam, pimozide, quinidine, sildenafil, sirolimus, and tacrolimus. The contraindication does not apply when mifepristone is used on a limited basis to terminate a pregnancy, but caution and close monitoring are advisable. Because mifepristone is eliminated slowly from the body, drug interactions may be observed for a prolonged period following discontinuation (approximately 2 to 3 weeks if mifepristone had been administered chronically to steady state).

References
1	He K, Woolf TF, Hollenberg PF "Mechanism-based inactivation of cytochrome P-450-3A4 by mifepristone (RU486)." J Pharmacol Exp Ther 288 (1999): 791-7. [PMID: 9918590]
2	Product Information. Korlym (mifepristone). Corcept Therapeutics Incorporated, Menlo Park, CA.
3	Product Information. Mifeprex (mifepristone) Danco Laboratories, New York, NY.