NONMEM -Reply

From: "Jogarao V. Gobburu" <GOBBURUJ@gunet.georgetown.edu> Subject: NONMEM -Reply Date: 9 Jul 1998 12:44:42 -0400 Dear Nagaraja, One problem could be the way you set your ETA for CL. If the ETA for CL is assumed to be additive (normal distr.), then it is finitely possible to encounter negative values of CL. A way of avoiding it is by using a proportional ETA: CL=THETA()*EXP(ETA()).This may be more meaningful too, in that, PK/PD parameters generally are log-normally distributed. I hope this helps. With regards, Joga Jogarao Gobburu, Center for Drug Development Science, Georgetown Univ., Washington DC.