Drug General Information (ID: DDIATOHVWP)
  Drug Name Mirtazapine Drug Info Enoxacin Drug Info
  Drug Type Small molecule Small molecule
  Therapeutic Class Antidepressants Antiinfective Agents
  Structure

 Mechanism of Mirtazapine-Enoxacin Interaction (Severity Level: Moderate)
     CYP450 enzyme inhibition Click to Show/Hide Mechanism Graph
Could Not Find 2D Structure
      Drug Name Mirtazapine Enoxacin
      Mechanism CYP450 1A2 substrate CYP450 1A2 inhibitor
      Key Mechanism Factor 1
Factor Name Cytochrome P450 1A2
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Structure Sequence
MALSQSVPFSATELLLASAIFCLVFWVLKGLRPRVPKGLKSPPEPWGWPLLGHVLTLGKNPHLALSRMSQRYGDVLQIRIGSTPVLVLSRLDTIRQALVRQGDDFKGRPDLYTSTLITDGQSLTFSTDSGPVWAARRRLAQNALNTFSIASDPASSSSCYLEEHVSKEAKALISRLQELMAGPGHFDPYNQVVVSVANVIGAMCFGQHFPESSDEMLSLVKNTHEFVETASSGNPLDFFPILRYLPNPALQRFKAFNQRFLWFLQKTVQEHYQDFDKNSVRDITGALFKHSKKGPRASGNLIPQEKIVNLVNDIFGAGFDTVTTAISWSLMYLVTKPEIQRKIQKELDTVIGRERRPRLSDRPQLPYLEAFILETFRHSSFLPFTIPHSTTRDTTLNGFYIPKKCCVFVNQWQVNHDPELWEDPSEFRPERFLTADGTAINKPLSEKMMLFGMGKRRCIGEVLAKWEIFLFLAILLQQLEFSVPPGVKVDLTPIYGLTMKHARCEHVQARLRFSIN
Gene Name CYP1A2
Uniprot ID CP1A2_HUMAN
KEGG Pathway hsa:1544
Protein Family Cytochrome P450 family
Protein Function
A cytochrome P450 monooxygenase involved in the metabolism of various endogenous substrates, including fatty acids, steroid hormones and vitamins (PubMed:9435160, PubMed:10681376, PubMed:11555828, PubMed:12865317, PubMed:19965576). 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:9435160, PubMed:10681376, PubMed:11555828, PubMed:12865317, PubMed:19965576). Catalyzes the hydroxylation of carbon-hydrogen bonds (PubMed:11555828, PubMed:12865317). Exhibits high catalytic activity for the formation of hydroxyestrogens from estrone (E1) and 17beta-estradiol (E2), namely 2-hydroxy E1 and E2 (PubMed:11555828, PubMed:12865317). Metabolizes cholesterol toward 25-hydroxycholesterol, a physiological regulator of cellular cholesterol homeostasis (PubMed:21576599). May act as a major enzyme for all-trans retinoic acid biosynthesis in the liver. Catalyzes two successive oxidative transformation of all-trans retinol to all-trans retinal and then to the active form all-trans retinoic acid (PubMed:10681376). Primarily catalyzes stereoselective epoxidation of the last double bond of polyunsaturated fatty acids (PUFA), displaying a strong preference for the (R,S) stereoisomer (PubMed:19965576). Catalyzes bisallylic hydroxylation and omega-1 hydroxylation of PUFA (PubMed:9435160). May also participate in eicosanoids metabolism by converting hydroperoxide species into oxo metabolites (lipoxygenase-like reaction, NADPH-independent) (PubMed:21068195). Plays a role in the oxidative metabolism of xenobiotics. Catalyzes the N-hydroxylation of heterocyclic amines and the O-deethylation of phenacetin (PubMed:14725854). Metabolizes caffeine via N3-demethylation (Probable).
    Click to Show/Hide
      Mechanism Description
  • Decreased metabolism of Mirtazapine caused by Enoxacin mediated inhibition of CYP450 enzyme

Recommended Action
      Management The possibility of prolonged and/or increased pharmacologic effects of mirtazapine should be considered during coadministration of drugs that inhibit CYP450 1A2, 2D6 and/or 3A4. Therapeutic response to mirtazapine should be monitored more closely following initiation, discontinuation, or dosing change of CYP450 inhibitors, and the mirtazapine dosage adjusted as necessary.

References
1 Okubo M, Murayama N, Miura J, Chiba Y, Yamazaki H "Effects of cytochrome P450 2D6 and 3A5 genotypes and possible coadministered medicines on the metabolic clearance of antidepressant mirtazapine in Japanese patients." Biochem Pharmacol 93 (2015): 104-9. [PMID: 25475885]
2 Product Information. Remeron (mirtazapine). Organon, West Orange, NJ.
3 Product Information. Varubi (rolapitant). Tesaro Inc., Waltham, MA.
4 Sitsen JM, Maris FA, Timmer CJ "Concomitant use of mirtazapine and cimetidine: a drug-drug interaction study in healthy male subjects." Eur J Clin Pharmacol 56 (2000): 389-94. [PMID: 11009047]
5 Stormer E, von Moltke LL, Shader RI, Greenblatt DJ "Metabolism of the antidepressant mirtazapine in vitro: contribution of cytochromes P-450 1A2, 2D6, and 3A4" Drug Metab Dispos 28 (2000): 1168-75. [PMID: 10997935]