Drug General Information (ID: DDI935A4IY)
  Drug Name Isradipine Drug Info Itraconazole Drug Info
  Drug Type Small molecule Small molecule
  Therapeutic Class Antihypertensive Agents Antifungal Agents
  Structure

 Mechanism of Isradipine-Itraconazole Interaction (Severity Level: Major)
     CYP450 enzyme inhibition Click to Show/Hide Mechanism Graph
Could Not Find 2D Structure
      Drug Name Isradipine Itraconazole
      Mechanism 1 CYP450 3A4 substrate CYP450 3A4 inhibitor
      Key Mechanism Factor 1
Factor Name Cytochrome P450 3A4
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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 Isradipine caused by Itraconazole mediated inhibition of CYP450 enzyme
     Additive cardiorespiratory depression effects Click to Show/Hide Mechanism Graph
Could Not Find 2D Structure
      Drug Name Isradipine Itraconazole
      Mechanism 2 Cardiac depressant effects Cardiac depressant effects
      Key Mechanism Factor 2
Factor Name Cardiorespiratory depression effects
Factor Description Cardiorespiratory depression is a reduction or inhibition of the normal function of the heart and lungs. The heart and lungs are the most important organs of the body's circulatory system, and when excessively depressed may result in decreased heart rate, decreased blood pressure, heart failure, slowed breathing (little to no visible chest movement), apnea, narrowed or pinpoint pupils, and seizures.
      Mechanism Description
  • Additive cardiorespiratory depression effects by the combination of Isradipine and Itraconazole 

Recommended Action
      Management Caution is advised if itraconazole must be used concomitantly with CCBs. Close monitoring of clinical response and tolerance is recommended, and patients should be advised to seek medical attention if they experience edema or swelling of the lower extremities sudden, unexplained weight gain difficulty breathing chest pain or tightness or hypotension as indicated by dizziness, fainting, or orthostasis. Appropriate dosage adjustment of the CCB may be necessary when used with itraconazole. Some authorities consider concomitant administration of bepridil and itraconazole to be contraindicated during and for 2 weeks after treatment with itraconazole.

References
1 Cerner Multum, Inc. "Australian Product Information.".
2 Product Information. Sporanox (itraconazole). Janssen Pharmaceutica, Titusville, NJ.
3 Rosen T "Debilitating edema associated with itraconazole therapy." Arch Dermatol 130 (1994): 260-1. [PMID: 8304774]