Re: Simultaneous pk model of 2 drugs
Hi Chris,
I think that the most straight-forward way to handle this is to have two sets
of compartments and write the $DES block manually (or writing the algebraic
equations if it's a one- or two-compartment model).
It wouldn't be straight-forward to model if the subjects receive the drugs at
the same time. If the drugs are received at separate times (like different
periods of a study or even different studies), then the DVID flag idea would
work, too.
There are only five EVID values as far as I know, and there's not a subtle way
to use them for two doses, I don't think:
• 0= observation
• 1= dose
• 2= other (I usually use it to reset the compartment)
• 3= reset the subject
• 4= reset and dose at the same time
Thanks,
Bill
Quoted reply history
> On Sep 2, 2016, at 1:22 PM, Penland, Chris <[email protected]>
> wrote:
>
> Greetings NMusers,
>
> Does nonmem have the capacity, unbeknownst to me, for modeling two
> simultaneous drugs?
>
> I would like some suggestions about how to define the dataset and model for a
> subcutaneous drug and oral drug being administered on different schedules. I
> would use DVID = 1 and 2 for the two plasma pk observations. I figure this
> soft of thing had to be dealt with in the past when trying to model dynamic
> DDIs (vs, just taking one of the drugs as a covariate on the other’s
> parameters).
>
> One approach is to specify the compartments for each to be dosed into then
> have those feed the central, but I’m curious to see if there is something
> more subtle in the nonmem syntax. Is there something about EVID, that I don’t
> know that would help (beyond EVID=1 for dosing)
>
> What if you had two oral drugs? Would you treat the two dosing compartments
> as separate and possibly link them together at the parameter/covariance level?
>
> Thanks,
> Chris
>
>
> Chris Penland, PhD
> ECD / Quantitative Clinical Pharmacology
> Waltham, MA USA
>
>
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