Significant levels of intracellular stavudine triphosphate are found in HIV-infected zidovudine-treated patients.

Design And Objective: It has been previously shown that zidovudine (ZDV) and its phosphorylated metabolites can be chemically reduced into the corresponding stavudine (d4T) forms in solution. The aim of this study was to search for intracellular d4T-triphosphate (TP) in patients receiving ZDV therapy as part of highly active antiretroviral therapy and to examine the ratio of concentrations of d4T-TP : ZDV-TP in these patients.

Methods: Seven ml of blood were sampled between 0.