Drug General Information (ID: DDIFEW051C)
  Drug Name Conivaptan Drug Info Methylprednisolone Drug Info
  Drug Type Small molecule Small molecule
  Therapeutic Class Vasopressin Antagonists Antineoplastics
  Structure

 Mechanism of Conivaptan-Methylprednisolone Interaction (Severity Level: Major)
     CYP450 enzyme inhibition Click to Show/Hide Mechanism Graph
Could Not Find 2D Structure
      Drug Name Conivaptan Methylprednisolone
      Mechanism CYP450 3A4 inhibitor CYP450 3A4 substrate
      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 Methylprednisolone caused by Conivaptan mediated inhibition of CYP450 enzyme

Recommended Action
      Management The possibility of increased corticosteroid effects should be considered when methylprednisolone is used with potent CYP450 3A4 inhibitors. Coadministration is not recommended unless the potential benefit to the patient outweighs the risk. If concomitant use is necessary, a 50% reduction in methylprednisolone dosage has been recommended by some investigators. Patients should be monitored for signs and symptoms of hypercorticism such as acne, striae, thinning of the skin, easy bruising, moon facies, dorsocervical "buffalo" hump, truncal obesity, increased appetite, acute weight gain, edema, hypertension, hirsutism, hyperhidrosis, proximal muscle wasting and weakness, glucose intolerance, exacerbation of preexisting diabetes, depression, and menstrual disorders. Other systemic glucocorticoid effects may include adrenal suppression, immunosuppression, posterior subcapsular cataracts, glaucoma, bone loss, and growth retardation in children and adolescents. Following extensive use with a potent CYP450 3A4 inhibitor, a progressive dosage reduction may be required over a longer period if methylprednisolone is to be withdrawn from therapy, as there may be a significant risk of adrenal suppression. Signs and symptoms of adrenal insufficiency include anorexia, hypoglycemia, nausea, vomiting, weight loss, muscle wasting, fatigue, weakness, dizziness, postural hypotension, depression, and adrenal crisis manifested as inability to respond to stress (e.g., illness, infection, surgery, trauma).

References
1 Agencia Espaola de Medicamentos y Productos Sanitarios Healthcare "Centro de informacion online de medicamentos de la AEMPS - CIMA.".
2 EMEA. European Medicines Agency "EPARs. European Union Public Assessment Reports.".
3 Glynn AM, Slaughter RL, Brass C, et al "Effects of ketoconazole on methylprednisolone pharmacokinetics and cortisol secretion." Clin Pharmacol Ther 39 (1986): 654-9. [PMID: 3709030]
4 Kandrotas RJ, Slaughter RL, Brass C, Jusko WJ "Ketoconazole effects on methylprednisolone disposition and their joint suppression of endogenous cortisol." Clin Pharmacol Ther 42 (1987): 465-70. [PMID: 3311551]
5 Kotlyar M, Brewer ER, Golding M, Carson SW "Nefazodone inhibits methylprednisolone disposition and enhances its adrenal-suppressant effect." J Clin Psychopharmacol 23 (2003): 652-6. [PMID: 14624194]
6 LaForce CF, Szefler SJ, Miller MF, Ebling W, Brenner M "Inhibition of methylprednisolone elimination in the presence of erythromycin therapy." J Allergy Clin Immunol 72 (1983): 34-9. [PMID: 6602160]
7 Varis T, Backman JT, Kivisto KT, Neuvonen PJ "Diltiazem and mibefradil increase the plasma concentrations and greatly enhance the adrenal-suppressant effect of oral methylprednisolone." Clin Pharmacol Ther 67 (2000): 215-21. [PMID: 10741623]
8 Varis T, Kaukonen KM, Kivisto KT, Neuvonen PJ "Plasma concentrations and effects of oral methylprednisolone are considerably increased by itraconazole." Clin Pharmacol Ther 64 (1998): 363-8. [PMID: 9797792]