title: Population pharmacokinetics of lopinavir in combination with rifampicin-based antitubercular treatment in HIV-infected South African children.
abstract: OBJECTIVE
  The population pharmacokinetics (PK) of lopinavir in tuberculosis (TB)/human immunodeficiency virus (HIV) co-infected South African children taking super-boosted lopinavir (lopinavir/ritonavir ratio 1:1) as part of antiretroviral treatment in the presence of rifampicin were compared with the population PK of lopinavir in HIV-infected South African children taking standard doses of lopinavir/ritonavir (ratio 4:1).
  
  
  METHODS
  Lopinavir concentrations were measured in 15 TB/HIV-co-infected paediatric patients who were sampled during and after rifampicin-based TB treatment and in 15 HIV-infected children without TB. During TB therapy, the dose of ritonavir was increased to lopinavir/ritonavir 1:1 in order to compensate for the induction of rifampicin. The children received median (interquartile range=IQR) doses of lopinavir 292 mg/m(2) (274, 309) and ritonavir 301 mg/m(2) (286, 309) twice daily. After TB treatment completion the children received standard doses of lopinavir/ritonavir 4:1 (median [IQR] lopinavir dose 289 mg/m(2) [286, 303] twice daily) as did those without TB (median [IQR] lopinavir dose 265 mg/m(2) [249, 289] twice daily).
  
  
  RESULTS
  Lopinavir oral clearance (CL/F) was about 30% lower in children without TB than in co-infected children treated with super-boosted lopinavir. However, the predicted lopinavir C(min) was above the recommended minimum therapeutic concentration during TB/HIV co-treatment in the 15 children. Lopinavir CL/F increased linearly during the dosing interval.
  
  
  CONCLUSIONS
  Increasing the ritonavir dose to achieve a lopinavir/ritonavir ratio of 1:1 when given in combination with rifampicin-based TB treatment did not completely compensate for the enhancement of lopinavir CL/F caused by rifampicin. The time-dependent lopinavir CL/F might be due to a time-dependent recovery from ritonavir inhibition of lopinavir metabolism during the dosing interval.
authors.affiliation: Department of Pharmaceutical Biosciences, Uppsala University, Box 591, BMC, 751 24 Uppsala, Sweden.
authors.forename: Doaa
authors.initials: D
authors.lastname: Elsherbiny
authors.forename: Yuan
authors.initials: Y
authors.lastname: Ren
authors.forename: Helen
authors.initials: H
authors.lastname: McIlleron
authors.forename: Gary
authors.initials: G
authors.lastname: Maartens
authors.forename: Ulrika S H
authors.initials: US
authors.lastname: Simonsson
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000188:drug therapy / Q000378:metabolism*; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000378:metabolism*; D017320:HIV Protease Inhibitors / Q000493:pharmacokinetics; D006801:Humans; D007223:Infant; D061466:Lopinavir; D008297:Male; D011744:Pyrimidinones / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D012293:Rifampin / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D019438:Ritonavir / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D013019:South Africa; D013997:Time Factors; D016896:Treatment Outcome; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy / Q000378:metabolism*
chemical_list: D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D011744:Pyrimidinones; D061466:Lopinavir; D019438:Ritonavir; D012293:Rifampin