Details of Drug Interaction | MecDDI

Drug General Information (ID: DDIEB53O9R)
Drug Name			Cimetidine		Drug Info		Cisapride		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antiulcer Agents				Gastrointestinal Agents
Structure

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

Drug Name		Cimetidine				Cisapride
Mechanism		CYP450 3A4 inhibitor				CYP450 3A4 substrate
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 Cisapride caused by Cimetidine mediated inhibition of CYP450 enzyme

Recommended Action
Management		Given the potential for serious and life-threatening adverse cardiac events associated with increased plasma levels of cisapride, concurrent use of cimetidine should be avoided if possible. Other H2-receptor antagonists (e.g., famotidine, nizatidine, ranitidine) have not been shown to significantly inhibit CYP450 3A4 and may be safer alternatives during therapy with cisapride.

References
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2	Bran S, Murray WA, Hirsch IB, Palmer JP "Long QT syndrome during high-dose cisapride." Arch Intern Med 155 (1995): 765-8. [PMID: 7695465]
3	Desta Z, Soukhova N, Mahal SK, Flockhart DA "Interaction of cisapride with the human cytochrome P450 system: metabolism and inhibition studies." Drug Metab Dispos 28 (2000): 789-800. [PMID: 10859153]
4	Dresser GK, Spence JD, Bailey DG "Pharmacokinetic-pharmacodynamic consequences and clinical relevance of cytochrome P450 3A4 inhibition." Clin Pharmacokinet 38 (2000): 41-57. [PMID: 10668858]
5	Gray VS "Syncopal episodes associated with cisapride and concurrent drugs." Ann Pharmacother 32 (1998): 648-51. [PMID: 9640482]
6	Hill SL, Evangelista JK, Pizzi AM, Mobassaleh M, Fulton DR, Berul CI "Proarrhythmia associated with cisapride in children." Pediatrics 101 (1998): 1053-6. [PMID: 9606235]
7	Kirch W, Janisch HD, Ohnhaus EE, van Peer A "Cisapride-cimetidine interaction: enhanced cisapride bioavailability and accelerated cimetidine absorption." Ther Drug Monit 11 (1989): 411-4. [PMID: 2741189]
8	Lewin MB, Bryant RM, Fenrich AL, Grifka RG "Cisapride-induced long QT interval." J Pediatr 128 (1996): 279-81. [PMID: 8636830]
9	Michalets EL, Williams CR "Drug interactions with cisapride: clinical implications." Clin Pharmacokinet 39 (2000): 49-75. [PMID: 10926350]
10	Product Information. Propulsid (cisapride). Janssen Pharmaceutica, Titusville, NJ.