NONMEM Users Network Archive

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Re: [NMusers] variation of time values in output data

From: Leonid Gibiansky <lgibiansky_at_quantpharm.com>
Date: Mon, 20 Apr 2015 13:21:43 -0400

it could be rounding issue when the precision of the TIME in the data
file exceeds the precision of the TIME in the output of the table. You
could increase precision of the output using format statement (see
manual). Other than that, NONMEM should not change TIME variable.

Leonid

--------------------------------------
Leonid Gibiansky, Ph.D.
President, QuantPharm LLC
web: www.quantpharm.com
e-mail: LGibiansky at quantpharm.com
tel: (301) 767 5566



On 4/20/2015 12:12 PM, Diane-Charlotte Imbs wrote:
> Dear nonmem users,
>
> We used the option “-2 RATE” of NONMEM (actual rate of infusion is
> unknown): within the control stream:
>
> D1=THETA(1)
>
> Moreover, since several infusions are given to the same patients, we
> have added an inter-occasion variability on D1 (see code below)*
>
> We obtained nice fit BUT in the OUTPUT DATA: TIME values corresponding
> to blood samples (and DV) are not identical to the actual TIME values of
> the INPUT data !?
>
> It seems that NONMEM program adjusts rate values, their interoccasion
> variability, and sampling times to have a good fit
>
> *How to fix TIME value corresponding to blood samples ? Indeed, we do
> not know the actual infusion rate but we do know the sampling times.*
>
> **
>
> Can anyone tell me if I chose the right model or help me resolving this?
>
> Thanks in advance,
>
> *$PK
>
> OCC1=0
>
> OCC2=0
>
> IF(DATE.EQ.1) OCC1=1
>
> IF(DATE.EQ.2) OCC2=1
>
> D1=THETA(1)*EXP(ETA(3)+ETA(4)*OCC1+ETA(5)*OCC2)
>
> $THETA (0,168,);D1
>
> $OMEGA .1 ; iiv d1
>
> $OMEGA BLOCK(1) .01 ; iov ETA4 OCC1
>
> $OMEGA BLOCK(1) SAME ; iov ETA5 OCC2
>
>
> *Loïc FIEVET*
>
> */Interne IPR en pharmacocinétique (1^er semestre)/*
>
> *Institut Universitaire du Cancer Toulouse - Oncopole*
>
> 1 avenue Irène Joliot-Curie
>
> 31059 TOULOUSE Cedex 9
>
>
Received on Mon Apr 20 2015 - 13:21:43 EDT

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