Drug General Information (ID: DDIH2UGQX1)
  Drug Name Atorvastatin Drug Info Fosamprenavir Drug Info
  Drug Type Small molecule Small molecule
  Therapeutic Class Statins/Antihyperlipidemic Agents Anti-Hiv Agents
  Structure

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

Recommended Action
      Management The benefits of using atorvastatin in combination with protease inhibitors should be carefully weighed against the potentially increased risk of myopathy including rhabdomyolysis. A lower dosage of atorvastatin should be considered if concomitant use is required. Atorvastatin labeling recommends that the dosage not exceed 20 mg/day when used in combination with fosamprenavir or with dual protease inhibitor therapy consisting of ritonavir plus darunavir, saquinavir, or fosamprenavir. Use of atorvastatin with the fixed combination of atazanavir-cobicistat is not recommended. The dosage should not exceed 40 mg/day when used with nelfinavir. Fluvastatin, pitavastatin, and pravastatin may be safer alternatives, since they are not metabolized by CYP450 3A4. All patients receiving statin therapy should be advised to promptly report any unexplained muscle pain, tenderness or weakness, particularly if accompanied by fever, malaise and/or dark colored urine. Therapy should be discontinued if creatine kinase is markedly elevated in the absence of strenuous exercise or if myopathy is otherwise suspected or diagnosed.

References
1 Barry M, Mulcahy F, Merry C, Gibbons S, Back D "Pharmacokinetics and potential interactions amongst antiretroviral agents used to treat patients with HIV infection." Clin Pharmacokinet 36 (1999): 289-304. [PMID: 10320951]
2 Cerner Multum, Inc. "UK Summary of Product Characteristics.".
3 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]
4 Fichtenbaum CJ, Gerber JG, Rosenkranz SL, et al. "Pharmacokinetic interactions between protease inhibitors and statins in HIV seronegative volunteers: ACTG Study A5047." AIDS 16 (2002): 569-577. [PMID: 11873000]
5 Malaty LI, Kuper JJ "Drug interactions of HIV protease inhibitors." Drug Safety 20 (1999): 147-69. [PMID: 10082072]
6 Mangum EM, Graham KK "Lopinavir-Ritonavir: a new protease inhibitor." Pharmacotherapy 21 (2001): 1352-63. [PMID: 11714208]
7 Piliero PJ "Interaction between ritonavir and statins." Am J Med 112 (2002): 510-1. [PMID: 11959074]
8 Product Information. Agenerase (amprenavir). Glaxo Wellcome, Research Triangle Pk, NC.
9 Product Information. Crixivan (indinavir). Merck & Co, Inc, West Point, PA.
10 Product Information. Fortovase (saquinavir) Roche Laboratories, Nutley, NJ.
11 Product Information. Lexiva (fosamprenavir). GlaxoSmithKline, Research Triangle Park, NC.
12 Product Information. Norvir (ritonavir). Abbott Pharmaceutical, Abbott Park, IL.
13 Product Information. Prezista (darunavir). Ortho Biotech Inc, Bridgewater, NJ.
14 Product Information. Reyataz (atazanavir). Bristol-Myers Squibb, Princeton, NJ.
15 Product Information. Viracept (nelfinavir). Agouron Pharma Inc, La Jolla, CA.
16 US Food and Drug Administration "FACT SHEET FOR HEALTHCARE PROVIDERS EMERGENCY USE AUTHORIZATION FOR PAXLOVID.".