Details of Drug-Drug Interaction
| Drug General Information (ID: DDIFNZLWX1) | |||||||||
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| Drug Name | Vardenafil | Drug Info | Gemfibrozil | Drug Info | |||||
| Drug Type | Small molecule | Small molecule | |||||||
| Therapeutic Class | Impotence Agents | Antihyperammonia Agents | |||||||
| Structure | |||||||||
| Mechanism of Vardenafil-Gemfibrozil Interaction (Severity Level: Moderate) | |||||||||
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| CYP450 enzyme inhibition Click to Show/Hide Mechanism Graph | |||||||||
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| Drug Name | Vardenafil | Gemfibrozil | |||||||
| Mechanism | CYP450 2C9 substrate | CYP450 2C9 inhibitor | |||||||
| Key Mechanism Factor 1 | |||||||||
| Factor Name | Cytochrome P450 2C9 |
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Structure
Sequence
MDSLVVLVLCLSCLLLLSLWRQSSGRGKLPPGPTPLPVIGNILQIGIKDISKSLTNLSKVYGPVFTLYFGLKPIVVLHGYEAVKEALIDLGEEFSGRGIFPLAERANRGFGIVFSNGKKWKEIRRFSLMTLRNFGMGKRSIEDRVQEEARCLVEELRKTKASPCDPTFILGCAPCNVICSIIFHKRFDYKDQQFLNLMEKLNENIKILSSPWIQICNNFSPIIDYFPGTHNKLLKNVAFMKSYILEKVKEHQESMDMNNPQDFIDCFLMKMEKEKHNQPSEFTIESLENTAVDLFGAGTETTSTTLRYALLLLLKHPEVTAKVQEEIERVIGRNRSPCMQDRSHMPYTDAVVHEVQRYIDLLPTSLPHAVTCDIKFRNYLIPKGTTILISLTSVLHDNKEFPNPEMFDPHHFLDEGGNFKKSKYFMPFSAGKRICVGEALAGMELFLFLTSILQNFNLKSLVDPKNLDTTPVVNGFASVPPFYQLCFIPV
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| Gene Name | CYP2C9 | ||||||||
| Uniprot ID | CP2C9_HUMAN | ||||||||
| KEGG Pathway | hsa:1559 | ||||||||
| Protein Family | Cytochrome P450 family | ||||||||
| Protein Function |
A cytochrome P450 monooxygenase involved in the metabolism of various endogenous substrates, including fatty acids and steroids (PubMed:7574697, PubMed:9866708, PubMed:9435160, PubMed:12865317, PubMed:15766564, PubMed:19965576, 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) (PubMed:7574697, PubMed:9866708, PubMed:9435160, PubMed:12865317, PubMed:15766564, PubMed:19965576, PubMed:21576599). Catalyzes the epoxidation of double bonds of polyunsaturated fatty acids (PUFA) (PubMed:7574697, PubMed:15766564, PubMed:19965576, PubMed:9866708). Catalyzes the hydroxylation of carbon-hydrogen bonds. Metabolizes cholesterol toward 25-hydroxycholesterol, a physiological regulator of cellular cholesterol homeostasis (PubMed:21576599). Exhibits low catalytic activity for the formation of catechol estrogens from 17beta-estradiol (E2) and estrone (E1), namely 2-hydroxy E1 and E2 (PubMed:12865317). Catalyzes bisallylic hydroxylation and hydroxylation with double-bond migration of polyunsaturated fatty acids (PUFA) (PubMed:9866708, PubMed:9435160). Also metabolizes plant monoterpenes such as limonene. Oxygenates (R)- and (S)-limonene to produce carveol and perillyl alcohol (PubMed:11950794). Contributes to the wide pharmacokinetics variability of the metabolism of drugs such as S-warfarin, diclofenac, phenytoin, tolbutamide and losartan (PubMed:25994031).
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| Mechanism Description |
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| Recommended Action | |||||||||
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| Management | Dosage adjustments may be appropriate for vardenafil whenever a CYP450 3A4 and/or 2C9 inhibitor is added to or withdrawn from therapy based on efficacy and patient tolerance. The manufacturer recommends that an initial vardenafil dosage of 2.5 to 5 mg be used in patients treated concomitantly with a potent CYP450 3A4 inhibitor such as erythromycin, itraconazole, ketoconazole, indinavir, and ritonavir. | ||||||||
| References | |||||||||||||||||||
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| 1 | Product Information. Levitra (vardenafil). Bayer, West Haven, CT. | ||||||||||||||||||
| 2 | Product Information. Qelbree (viloxazine). Supernus Pharmaceuticals Inc, Rockville, MD. | ||||||||||||||||||