Pop PK/PD integrated plus differential equations

From:"Kakkar, Tarundeep" Subject:[NMusers] Pop PK/PD integrated plus differential equations Date:Tue, 11 Jun 2002 16:11:29 -0400 Hi, Is there a way in NONMEM where I can instruct it to fit an integrated equation (e.g, for a 2 comptt. model) for the PK data and a differential equation to fit the PD data simultaneously. I'm using ADVAN6 at this moment and the run time is long (I even fixed population PK estimates), therefore, I have been using POSTHOC estimates for PK at this moment. Thanks Tarun

From:"Sam Liao" Subject:RE: [NMusers] Pop PK/PD integrated plus differential equations Date: Fri, 14 Jun 2002 09:34:15 -0400 Tarun: I have used hybrid equations under $DES block to save run time in PK/PD modeling. Just make sure to define the integrated equation in the $DES block, not in the $PK block. I used the two-stage approach as you did in PK/PD modeling. But, I have not done simultaneous fit of PK and PD data using the hybrid equations. I would be interested to hear any discussion of the advantage of this approach over the two-stage approach. The run time is long even with the two-stage approaches. Best regards, Sam Liao, Ph.D. PharMax Research 270 Kerry Lane, Blue Bell, PA 19422 phone: 215-6541151 efax: 1-720-2946783