Hello NMUsers
I am trying to reanalyse some data using the M3 method (Ahn et al, Likelihood
based approaches to handling data below the quantification limit using NONMEM
VI, J Pharmacokinet Pharmacodyn. 2008). I had previously used M6 and wanted to
try something potentially more robust.
I'm h
Ann,
This error message usually means try NONMEM thinks your OMEGA initial
estimates are weird. A leading suspect would be the OMEGA estimates for
the two lag time parameters. Try fixing both of them to zero and see if
that gets your model going. If that doesn't work then you could try
fixin
Colleagues
I am installing NONMEM 7 for a colleague on a Windows 7 (64-bit) machine.
ifort is installed -- however, during the installation I encountered an error
message:
> Intel(R) Visual Fortran Compiler Professional Edition for Windows*
> modification can continue, but take note:
> The foll
Dear Nick
Many thanks for your reply :) The reason I am using $DES is because as my next
step will evaluate adding transit compartments to the model. I'm currently
trying to sort the late kinetics before I tackle the early disposition. I've
already investigated transit models with this data
Ann,
Try adding an additive error parameter. Data around the BQL are crying
out for an additive baseline noise component. A simple proportional
error model doesn't make any sense as concs approach LLOQ. By definition
the residual error CV must be increasing around the LLOQ.
e.g.
$THETA (0,
Ann,
I had run into similar problems. Here're some suggestions for you to
consider:
1. I had included only one post-Cmax BLQ value. It worked for my case.
2. One consultant proposed some boundaries on the parameters to constrain
the search. He also suggest me to stabilize my model first. It
Ann,
In addition to my early suggestion to include an additive error in your
residual error model here is another reason for doing that.
If you have any observations before the lag time then NONMEM will always
complain if you only have a proportional residual error model. This is
because the
