Re: Is “DOSE=0” accepted by NONMEM?
Dear Zheng,
NONMEM wants an amount there, or it won't interpret that record as a dose. On
the other hand, if you don't put anything into the system, or you do not
initialise the compartments (see below), nothing is going to happen.
If you want to use a dose to initialise the system, them you can put AMT=1 and
use the bioavailability parameter to decide how much to put it F1= YYY.
YYY can be then be a number in the data or a parameter.
If you want to use parameters, I suggest that you look into how to model
baselines
Dansirikul C, Silber HE, Karlsson MO. 2008. Approaches to handling
pharmacodynamic baseline responses. J. Pharmacokinet. Pharmacodyn. 35:269–283.
In the same paper there are also snippets of code on how to initialise
compartments with the command
A_0(1) = YYY
which is a somewhat neater option.
I would prefer the second option A_0_1, but I guess if you use some of the
basic ADVANs, NONMEM may expect a dose and give you an error if it doesn't find
one.
Good luck.
Paolo
Quoted reply history
On 2015/09/07 08:30, Zheng Liu wrote:
Dear NONMEM users,
I have a group of patients, whose plasma drug levels are measured and known at
time=0 (no further drug is given to the patients afterwards.). I try to know,
after how long time the drug will be completely cleared out from these
patients. Naturally I used NONMEM to fit the patients' V and CL, in order to
get plasma concentration change profile.
However seems NONMEM only accepts DOSE is a positive number. If DOSE=0, NONMEM
can't perform the fitting. Can anyone kindly give me some suggestions to solve
this problem? Thanks a lot in advance!
PTID DV AMT time EVID
2 . 0
0 1
2 6.8 0 0 0
2 1.1 0 3 0
2 0 0 6 0
3 . 0 0 1
3 1.08 0 0 0
3 0.16 0 3 0
3 0.03 0 6 0
3 0 0 9 0
Zheng
--
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Paolo Denti, PhD
Pharmacometrics Group
Division of Clinical Pharmacology
Department of Medicine
University of Cape Town
K45 Old Main Building
Groote Schuur Hospital
Observatory, Cape Town
7925 South Africa
phone: +27 21 404 7719
fax: +27 21 448 1989
email: [email protected]<mailto:[email protected]>
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