title: Tenofovir use in human immunodeficiency virus-1-infected children in the United kingdom and Ireland.
abstract: BACKGROUND
  Tenofovir disoproxil fumarate (TDF) is neither licensed for use nor extensively studied in HIV-infected children. The only available formulation is an adult tablet, introducing the possibility of dosing errors in children. TDF interacts with other antiretrovirals and has been associated with decline in renal function and CD4 count. We describe the use of TDF in a cohort of HIV-1-infected children in the United Kingdom and Ireland.
  
  
  METHODS
  Children ever prescribed TDF and followed in the Collaborative HIV Pediatric Study cohort since 2001 were included in analyses of dosing, adverse events, and virologic and immunologic response. Suspected adverse drug reactions to TDF reported to the Medicines and Healthcare products Regulatory Agency during the same time were also reviewed.
  
  
  RESULTS
  One hundred fifty-nine of 1253 children had taken TDF. They were older and had clinically more advanced disease than the rest of the cohort. Eighteen percent received >120% and 37% received <80% of the suggested pediatric dose (8 mg/kg). Thirty-seven percent of new TDF regimens contained didanosine (ddI), though few since 2005. Twelve of 159 (7.5%) children experienced serious adverse events and stopped TDF permanently, 11 taking concurrent lopinavir-ritonavir, and 10 ddI; 5 had renal toxicity. Viral load suppressed to < or =50 copies/mL at 12 months in 38% of those starting TDF. Median increase in CD4 count at 12 months was +110 cells/mL (interquartile range, 9-270), but only 3 cells/mL in those taking concurrent ddI.
  
  
  CONCLUSIONS
  TDF seems to be an effective antiretroviral drug in this pediatric cohort, although considerable underdosing and overdosing occurs. A small number of children experienced serious adverse events while taking TDF; half were renal toxicity, most associated with concurrent ddI and lopinavir-ritonavir use.
authors.affiliation: Royal Liverpool Children's NHS Trust, Liverpool, England. Andrew.riordan@rlc.nhs.uk
authors.forename: Andrew
authors.initials: A
authors.lastname: Riordan
authors.forename: Ali
authors.initials: A
authors.lastname: Judd
authors.forename: Katherine
authors.initials: K
authors.lastname: Boyd
authors.forename: David
authors.initials: D
authors.lastname: Cliff
authors.forename: Katia
authors.initials: K
authors.lastname: Doerholt
authors.forename: Hermione
authors.initials: H
authors.lastname: Lyall
authors.forename: Esse
authors.initials: E
authors.lastname: Menson
authors.forename: Karina
authors.initials: K
authors.lastname: Butler
authors.forename: Di
authors.initials: D
authors.lastname: Gibb
mesh_terms: D000225:Adenine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000293:Adolescent; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D002648:Child; D024882:Drug Resistance, Viral; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000821:virology; D006801:Humans; D007494:Ireland; D008297:Male; D063065:Organophosphonates / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D010372:Pediatrics; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D000068698:Tenofovir; D016896:Treatment Outcome; D006113:United Kingdom
chemical_list: D019380:Anti-HIV Agents; D063065:Organophosphonates; D018894:Reverse Transcriptase Inhibitors; D000068698:Tenofovir; D000225:Adenine