title: Effect of efavirenz on the pharmacokinetics of ketoconazole in HIV-infected patients.
abstract: OBJECTIVE
  To investigate the effect of efavirenz on the ketoconazole pharmacokinetics in HIV-infected patients.
  
  
  METHODS
  Twelve HIV-infected patients were assigned into a one-sequence, two-period pharmacokinetic interaction study. In phase one, the patients received 400 mg of ketoconazole as a single oral dose on day 1; in phase two, they received 600 mg of efavirenz once daily in combination with 150 mg of lamivudine and 30 or 40 mg of stavudine twice daily on days 2 to 16. On day 16, 400 mg of ketoconazole was added to the regimen as a single oral dose. Ketoconazole pharmacokinetics were studied on days 1 and 16.
  
  
  RESULTS
  Pretreatment with efavirenz significantly increased the clearance of ketoconazole by 201%. C(max) and AUC(0-24) were significantly decreased by 44 and 72%, respectively. The T ((1/2)) was significantly shorter by 58%.
  
  
  CONCLUSIONS
  Efavirenz has a strong inducing effect on the metabolism of ketoconazole.
authors.affiliation: Department of Medicine, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand. srsomcha@medicine.psu.ac.th
authors.forename: Somchai
authors.initials: S
authors.lastname: Sriwiriyajan
authors.forename: Werawath
authors.initials: W
authors.lastname: Mahatthanatrakul
authors.forename: Wibool
authors.initials: W
authors.lastname: Ridtitid
authors.forename: Sutep
authors.initials: S
authors.lastname: Jaruratanasirikul
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000188:drug therapy; D000328:Adult; D000480:Alkynes; D019380:Anti-HIV Agents / Q000494:pharmacology*; D000935:Antifungal Agents / Q000493:pharmacokinetics*; D019540:Area Under Curve; D048588:Benzoxazines / Q000494:pharmacology*; D002180:Candidiasis, Oral / Q000150:complications / Q000188:drug therapy; D003521:Cyclopropanes; D004347:Drug Interactions; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy; D006207:Half-Life; D006801:Humans; D007654:Ketoconazole / Q000493:pharmacokinetics*; D019259:Lamivudine; D008297:Male; D008875:Middle Aged; D018119:Stavudine
chemical_list: D000480:Alkynes; D019380:Anti-HIV Agents; D000935:Antifungal Agents; D048588:Benzoxazines; D003521:Cyclopropanes; D019259:Lamivudine; D018119:Stavudine; C098320:efavirenz; D007654:Ketoconazole