nonpositive value for CL / abort

From: "nelamangala nagaraja" <nvnagaraj@hotmail.com> Subject: nonpositive value for CL / abort Date: 9 Jul 1998 11:09:59 -0400 Hello everyone, I have started using NONMEM-V for population pharmacokinetics. I have been facing some problem in specifying a negative slope to any regression equation (like relationship between clearance and age). The output message says a nonpositive value for clearance and aborts the run. I tried both ways: (1) introducing (-) sign in the equation itself and (2) giving the negative value for lower constraint for the slope (THETA). The output message remains the same. Is it due to the large variability in the data or there is some other way of solving this problem. I should mention that the installation was done through SETUP.BAT (shortcut method). It would be nice if you could suggest me to solve this problem. Thanks for the help. With Regards, N.V. Nagaraja, Post Doc. Res. Assoc. Dept. of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL 32610 E-mail: nvnagaraj@hotmail.com Phone: (352)846-3257 Fax: (352)392-4447.