Re: Weight normailized doses in modeling

From: jlukas@usal.es Subject: Re: [NMusers] Weight normailized doses in modeling Date: Mon, 29 Oct 2001 11:28:54 MET Hello Thomas, Your model (1 comp PK) has no way of "knowing" the units of the object you are giving it as dose=AMT, so the parameters will not be scaled per kg. On the contrary, the magnitude of your AMT entry in nonmem may be incorrect with respect to your concentrations (which I assume are not scaled per kg) so the parameters may simply come out wrong. You could obtain scaled per kg parameters by setting e.g. TVCLW=THETA(1)*WT etc. within the model (and then maybe having to account for this in the S1 scales depending on what the units of your dose finally are and whether you also scaled V). In terms of how you actually introduce the AMT item, if you now have it in mg/kg for example then use S1=V/WT to scale for WT, if your concentrations are not already scaled. In any case, obviously, the units of the your modeled and observed concentrations must match. Apart from the references that Nick suggests you may also want to look at the theophylline problem in the nonmem manuals. I hope this helps! Cheers, John Lu kas Dept of Pharmacy University of Salamanca Spain + 34 647545633