From Thu Oct 24 02:26:12 1996
Subject: Deriving Cmax and the corresponding variability

Dear NONMEM users

I would like to derive Cmax (including the corresponding variability) as secondary parameter from a given NONMEM-analysis. Is there experience how to do it ?

Your comments and suggestions are greatly appreciated.

Thanks in advance,


From lewis Thu Oct 24 09:41:25 1996
Subject: Cmax

Some very simple models, such as the 1 compartment elimination with first order absorption, can be solved explicitly for Cmax as a function of whatever parameterization you are using. In such a case it is simple to reparameterize with Cmax as a parameter and one of the previous parameters, e.g., V, solved in terms of it and the other parameters. Where there is no explicit solution for Cmax (most cases), it will be harder. There is no problem finding Cmax: just simulate your model on a fine time grid and "read off" the value. To estimate its variability is more difficult: all I can think of is a bootstrap approach which is a general method for finding the variance of an estimator of any statistic whatever based on the data.

Good luck,