title: Influence of antiretroviral drugs on the pharmacokinetics of prednisolone in HIV-infected individuals.
abstract: BACKGROUND
  Corticosteroids are cytochrome P450 3A4 substrates, which have been associated with toxicities in patients receiving cytochrome P450 3A4 inhibitors such as human immunodeficiency virus protease inhibitors. In a study in healthy volunteers, ritonavir significantly increased prednisolone exposure.
  
  
  METHODS
  We investigated the influence of antiretroviral (ARV) medications on prednisolone pharmacokinetics in 3 groups of 10 human immunodeficiency virus-infected subjects. One group received lopinavir/ritonavir, and another efavirenz, as part of their ARV regimen; a third group did not receive ARV medications. Each subject received a single 20-mg prednisone dose followed by serial blood sampling for prednisolone. Prednisolone pharmacokinetics were compared among the groups.
  
  
  RESULTS
  Area under the concentration-time curve was significantly lower in efavirenz recipients versus subjects receiving lopinavir/ritonavir (geometric mean ratio = 0.60, P = 0.01). Average prednisolone area under the concentration-time curve was higher in subjects taking lopinavir/ritonavir versus subjects not on ARVs; however, this difference was not significant (P > 0.05).
  
  
  CONCLUSIONS
  These data indicate that prednisolone concentrations may fluctuate widely when human immunodeficiency virus-positive individuals established on efavirenz therapy change to lopinavir/ritonavir or vice versa.
authors.affiliation: Pharmacy Department, Warren G Magnuson Clinical Center, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Kristin H
authors.initials: KH
authors.lastname: Busse
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Formentini
authors.forename: Raul M
authors.initials: RM
authors.lastname: Alfaro
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Kovacs
authors.forename: Scott R
authors.initials: SR
authors.lastname: Penzak
mesh_terms: D000328:Adult; D000480:Alkynes; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D048588:Benzoxazines / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D003521:Cyclopropanes; D004347:Drug Interactions; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000378:metabolism* / Q000821:virology; D017320:HIV Protease Inhibitors / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D061466:Lopinavir; D008297:Male; D008875:Middle Aged; D011239:Prednisolone / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011744:Pyrimidinones / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D019438:Ritonavir / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; D017320:HIV Protease Inhibitors; D011744:Pyrimidinones; D018894:Reverse Transcriptase Inhibitors; D061466:Lopinavir; D011239:Prednisolone; C098320:efavirenz; D019438:Ritonavir