baseline models

From: Vinogradova Svetlana Date: September 22, 2011 technical Source: mail-archive.com
Dear Nonmem users, thank you much for your help, I have two more questions about baseline models. Now I've decided to fnd first the best baseline model, and then I'm going to analyse all the data. I'm dealing with heart rate (HR), and increasing (or decreasing) of HR because of treatmnet. 1) in standard model basenight parameter is limited to be positive, but I think it could be negitive, so is it ok? 2) when I run simple model with only BN and BD, BD is estimated to be about 70. It's ok, 'cause is ~mean HR. But when I try to introduce placebo effect, BD turnes out to be ~6, P0 ~ 60. OFV is better for placebo model, but physioligicaly it's not right! What should I do in such cases? Thank you much, Svetlana