Re: AW: [NMusers] Time 'T' in $Error

From: Jeroen Elassaiss-Schaap <jeroen_at_pd-value.com>
Date: Tue, 28 Jul 2015 15:26:00 +0200

Dear Katrin,


You still could code your model in $ERROR using TIME, as your diurnal
rhythm is proportional to baseline.

If you would like to explore indirect models, you could try the harmonic
approach as described in Chakraborty et al. 1999 -
http://europepmc.org/abstract/med/10533696; the beauty is that you can
model the baseline in $PRED and use these estimates right into $DES for
your drug effect on kin.

For blood pressure rhythms you might also want to try the more flexible
model laid out by Sallstrom et al. 2005,
http://europepmc.org/abstract/med/16328099.

Hope this helps,
Jeroen


--

http://pd-value.com
jeroen_at_pd-value.com
_at_PD_value
+31 6 23118438
-- More value out of your data!


Op 28-07-15 om 08:07 schreef Katrin Volz:
>
> Dear Bill, dear all
>
> Thanks so much for your answer.
>
> More concrete I would like to model blood pressure including a
> circadian rhythm. Therefore I would like to use a sine or cosine
> function with ‘T’ instead of ‘Time’.
>
> SinfS = ( 1 + Amplitude * sin ( (2*PI/Period) * (T-Phase) ) ) ; sine
> or cosine function
>
> SBP = (SBas + SinfS) * (1-EffS)
> ; SBP = systolic
> blood pressure, SBas = Baseline systolic blood pressure, (1-EffS = effect)
>
> I could also model this effect using a turnover model and avoid this
> problem, but I would like to evaluate this kind of PD model (if there
> is any meaningful way to code).
>
> I also had the idea to code this sine function as a function of time
> in a compartment and rename this compartment in $Error, but I am not
> sure if there is any way to do this.
>
> Thanks again and best regards.
>
> Katrin
>
> *Von:*Denney, William S. [mailto:William.S.Denney_at_pfizer.com]
> *Gesendet:* 27 July 2015 17:34
> *An:* Katrin Volz <ankekatrin.volz_at_uni-saarland.de>;
> nmusers_at_globomaxnm.com
> *Betreff:* RE: [NMusers] Time 'T' in $Error
>
> Hi Katrin,
>
> $ERROR is executed once per data row. The time when $ERROR is run is
> the TIME value (the discrete times of the measurement). For this
> specific example, you can just use TIME. You will need to code your
> $DES block so that what you’re wanting to integrate as a function of
> time is in a compartment amount (e.g. A(1)). With your example, it’s
> hard to see how T is used in the $DES, but perhaps you could share the
> real example to give a bit more concrete advice on how to integrate
> the answer into your code.
>
> Thanks,
>
> Bill
>
> *From:*owner-nmusers_at_globomaxnm.com
> <mailto:owner-nmusers_at_globomaxnm.com>
> [mailto:owner-nmusers_at_globomaxnm.com] *On Behalf Of *Katrin Volz
> *Sent:* Monday, July 27, 2015 10:46 AM
> *To:* nmusers_at_globomaxnm.com <mailto:nmusers_at_globomaxnm.com>
> *Subject:* [NMusers] Time 'T' in $Error
>
> Dear NMuser,
>
> I would like to model a PD effect using a function which includes
> continuous time ‘ T ’.
>
> The PD Effect is coded in $Error.
>
> In general like this:
>
> *$ERROR*
>
> MyFunction = xxx + T
>
> PDEffect = Basline * MyFunction
>
> But ‘T’ cannot be used in $Error.
>
> I tried to code the function with ‘T’ in $DES and rename it to use it
> in $ERROR:
>
> *$DES*
>
> MyFunction = xxx + T
>
> *$ERROR*
>
> MyNewFunction = MyFunction
>
> PDEffect = Baseline * MyNewFunction
>
> but it didn’t worked (to rename was not permitted by NONMEM).
>
> Does anyone of you has an idea how to solve this problem?
>
> Thanks and best regards.
>
> Katrin
>
> Anke-Katrin Volz
>
> PhD Student
>
> Saarland University
>
> Clinical Pharmacy
>
> Campus C2 2 | Room 0.31
>
> D- 66123 Saarbrücken
>
> mail ankekatrin.volz_at_uni-saarland.de
> <mailto:ankekatrin.volz_at_uni-saarland.de>
>
> fon +49 [0]681 302 22 84
>
> fax +49 [0]681 302 70 258
>
> www.clinicalpharmacy.me <http://www.clinicalpharmacy.me>
>


Received on Tue Jul 28 2015 - 09:26:00 EDT

This archive was generated by hypermail 2.3.0 : Fri Sep 27 2019 - 16:45:17 EDT