Pharmacokinetics and pharmacodynamics of indinavir with or without low-dose ritonavir in HIV-infected Thai patients.
OBJECTIVE
To describe the pharmacokinetics and pharmacodynamics of indinavir with or without low-dose ritonavir in human immunodeficiency virus (HIV)-infected Thai patients.


METHODS
Thirty-six HIV-1-infected patients who participated in HIV-NAT 005 study gave informed consent to record a pharmacokinetic curve 4 weeks after starting a regimen containing either indinavir 800 mg every 8 h (n = 19) or indinavir 800 mg + ritonavir 100 mg every 12 h (n = 17). Indinavir plasma concentrations were measured by HPLC. Pharmacokinetic parameters were calculated by non-compartmental methods.


RESULTS
The median (interquartile range; IQR) body weight of the 36 patients (11 females and 25 males) was 60 (54-72) kg. Median and IQR values for indinavir AUC, Cmax and Cmin were 20.9 (13.1-27.0) mg x h/L, 8.1 (6.6-9.4) mg/L and 0.13 (0.09-0.27) mg/L, respectively, for indinavir 800 mg every 8 h, and 49.2 (42.5-60.4) mg x h/L, 10.6 (8.5-13.2) mg/L and 0.68 (0.43-0.77) mg/L, respectively, for indinavir 800 mg + ritonavir 100 mg every 12 h. These values are not largely different from values found in Caucasian patients, with the exception of relatively high peak levels of indinavir in Thai subjects. Cut-off values for optimal virological efficacy were an indinavir Cmin of 0.10 and 0.25 mg/L for the every 8 h and the every 12 h regimen, respectively; patients with an indinavir AUC greater than 30 (every 8 h regimen) or 60 (every 12 h regimen) mg x h/L were at increased risk of developing nephrotoxicity.


CONCLUSIONS
Indinavir pharmacokinetics and pharmacodynamics in Thai HIV-1-infected patients are similar to those described in Caucasian patients, despite an overall lower body weight in this population
Burger
David
D
Department of Clinical Pharmacy, 533 University Medical Centre Nijmegen, Geert Grooteplein 8, 6525 GA Nijmegen, The Netherlands. D.Burger@akf.umcn.nl
Boyd
Mark
M
Duncombe
Chris
C
Felderhof
Mariet
M
Mahanontharit
Apicha
A
Ruxrungtham
Kiat
K
Ubolyam
Sasiwimol
S
Stek
Michael
M
Cooper
David
D
Lange
Joep
J
Phanupak
Praphan
P
Reiss
Peter
P
D000328:Adult; D019540:Area Under Curve; D001835:Body Weight / Q000502:physiology; D002851:Chromatography, High Pressure Liquid; D004347:Drug Interactions; D005260:Female; D015658:HIV Infections / Q000378:metabolism*; D017320:HIV Protease Inhibitors / Q000009:adverse effects / Q000493:pharmacokinetics*; D006207:Half-Life; D006801:Humans; D019469:Indinavir / Q000009:adverse effects / Q000493:pharmacokinetics*; D007674:Kidney Diseases / Q000139:chemically induced; D008297:Male; D019438:Ritonavir / Q000009:adverse effects / Q000493:pharmacokinetics*; D013785:Thailand
D017320:HIV Protease Inhibitors; D019469:Indinavir; D019438:Ritonavir