title: CYP2C metabolism of oral antidiabetic drugs--impact on pharmacokinetics, drug interactions and pharmacogenetic aspects.
abstract: BACKGROUND
  The cytochrome P4502C enzymes account for the metabolism of approximately 20% of therapeutic drugs including certain oral antidiabetic drugs (OADs).
  
  
  METHODS
  This review focuses on the effect of CYP2C enzymes on metabolism of sulphonylureas (SUs), meglitinides, and thiazolidinediones (TZDs) discussing their impact on pharmacokinetics, drug interactions and toxicological profiles. Pharmacogenetic aspects reflecting individual gene variants and variable drug effects are also considered.
  
  
  CONCLUSIONS
  Genetic polymorphisms of CYP2C9 enzymes (*2/*2, *2/*3, *3/*3) influence the glycaemic response to SUs and impair their substrate metabolism. Restricted data from small-sized studies with heterogenous definitions of hypoglycaemia revealed no clear association between CYP2C9 genotypes and the risk of hypoglycaemia. Functional polymorphisms of CYP2C8- and CYP2C9 drug metabolizing genes affect markedly pharmacokinetics of meglitinides. Compared to wild-type carriers, patients treated with TZDs and carrying the common CYP2C8*3 and *4 variants showed a reduced glycaemic control. The strong CYP2C8 and OATP1B1 inhibitor gemfibrozil increases substantially the plasma concentrations of repaglinide and TZDs. Numerous metabolic drug interactions exist between SUs and commonly prescribed drugs, especially anti-infectives. The complex pharmacokinetic and pharmacogenetic properties and the unfavourable short and long term risk profile of glibenclamide and glimepiride raise the question whether their use can be justified any longer.
authors.affiliation: Lippe-Detmold Hospital, First Department of Medicine, Röntgenstr. 18, Detmold, 32756, Germany. Andreas.Holstein@t-online.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Holstein
authors.forename: Winfried
authors.initials: W
authors.lastname: Beil
authors.forename: Peter
authors.initials: P
authors.lastname: Kovacs
mesh_terms: D000284:Administration, Oral; D001549:Benzamides / Q000009:adverse effects / Q000493:pharmacokinetics; D001786:Blood Glucose / Q000032:analysis; D002219:Carbamates / Q000009:adverse effects / Q000493:pharmacokinetics; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D004347:Drug Interactions; D015248:Gemfibrozil / Q000009:adverse effects / Q000493:pharmacokinetics; D006801:Humans; D007004:Hypoglycemic Agents / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D008658:Inactivation, Metabolic; D010597:Pharmacogenetics; D010880:Piperidines / Q000009:adverse effects / Q000493:pharmacokinetics; D020641:Polymorphism, Single Nucleotide; D013453:Sulfonylurea Compounds / Q000009:adverse effects / Q000493:pharmacokinetics; D045162:Thiazolidinediones / Q000009:adverse effects / Q000493:pharmacokinetics
chemical_list: D001549:Benzamides; D001786:Blood Glucose; D002219:Carbamates; D007004:Hypoglycemic Agents; D010880:Piperidines; D013453:Sulfonylurea Compounds; D045162:Thiazolidinediones; C400322:cytochrome P-450 CYP2C subfamily; C072379:repaglinide; C057619:glimepiride; C030516:meglitinide; D003577:Cytochrome P-450 Enzyme System; D015248:Gemfibrozil