time variant covariate ?

Date: Thu, 10 Jun 1999 12:35:30 -0400 From: Nagaraja <nagaraja@ufl.edu> Subject: time variant covariate ? Dear NONMEM users, I am modeling the quinine population pharmacokinetics. I would like to analyze the relationship between the volume of PK parameters and the hematocrit. However, I have different values of hematocrit at each of the time points. Is it possible to input time variant covariable in a population analysis. Or is it better to analyze the relationship as PK-PD between quinine concentrations and the hematocrit. I am waiting for your kind suggestions and Thanks in advance. Raj N.V. Nagaraja, Post Doc. Res. Associate Dept of Pharmaceutics, University of Florida, Gainesville, FL-32610