Nevirapine, stavudine and lamivudine pharmacokinetics in African children on paediatric fixed-dose combination tablets.
OBJECTIVE
Triomune Baby and Junior have been developed in response to the urgent need for appropriate paediatric fixed-dose combination antiretroviral tablets, with higher nevirapine to stavudine and lamivudine ratios than adult tablets, in accordance with paediatric recommendations. We determined whether this ratio results in optimal exposure in the target population.


METHODS
Seventy-one Zambian children were treated with Triomune Baby or Junior dosed according to weight bands. After 4 weeks or more, a 12-h pharmacokinetic curve was recorded. Antiretroviral plasma concentrations were assayed by high-performance liquid chromatography.


RESULTS
Six children were excluded because of poor adherence. Of the remaining 65, 24 (37%) were female, 24 (37%) weighed less than 15 kg and most were malnourished. Mean (range) nevirapine C12h, Cmax and AUC12h of 6.0 (1.4, 16.9) mg/l, 10.0 (3.8, 22.5) mg/l and 94.4 (32.1, 232) mg/l per hour were higher than those reported in adults. Nevirapine C12h was subtherapeutic (< 3.0 mg/l) in four children (6%). Mean stavudine and lamivudine C12h, Cmax, AUC12h (< 0.015 mg/l, 0.45 mg/l, 1.05 mg/l per hour and 0.09 mg/l, 1.33 mg/l, 5.42 mg/l per hour) were comparable to adults. There was no evidence of a difference in nevirapine AUC12h across weight bands (P = 0.2), whereas the difference in stavudine (P = 0.0003) and lamivudine AUC12h (P = 0.01) was driven by the single weight band with unequal dosing.


CONCLUSIONS
Nevirapine concentrations were higher but more variable than in adults; the pharmacokinetic parameters of stavudine and lamivudine were comparable to adults. As nevirapine underdosing is of greater concern than overdosing, the Triomune Baby and Junior ratio appears to be appropriate for children weighing 6 kg and over. Further research is required for children under 6 kg.
L'homme
Rafaëlla F A
RF
Department of Clinical Pharmacy, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands.
Kabamba
Desiré
D
Ewings
Fiona M
FM
Mulenga
Veronica
V
Kankasa
Chipepo
C
Thomason
Margaret J
MJ
Walker
A Sarah
AS
Chintu
Chifumbe
C
Burger
David M
DM
Gibb
Diana M
DM
D000293:Adolescent; D023241:Antiretroviral Therapy, Highly Active; D019540:Area Under Curve; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D004334:Drug Administration Schedule; D004338:Drug Combinations; D016903:Drug Monitoring / Q000379:methods; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000378:metabolism; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D019259:Lamivudine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008297:Male; D019829:Nevirapine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D018894:Reverse Transcriptase Inhibitors / Q000493:pharmacokinetics* / Q000627:therapeutic use; D018119:Stavudine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D015024:Zambia
D004338:Drug Combinations; D018894:Reverse Transcriptase Inhibitors; D019259:Lamivudine; D019829:Nevirapine; D018119:Stavudine