Re: Interoccasion variability

Date: Fri, 17 Sep 1999 11:13:44 -0400 (EDT) From: Jogarao Gobburu 301-594-5661 FAX 301-480-8329 <GOBBURUJ@cder.fda.gov> Subject: Re: Interoccasion variability Kevin, You can model IOC as follows using NONMEM: Lets say, you are interested in estimating IOC of CL across three occassions (OCC1,OCC2,OCC3) coded using dummy variables, then ... $PK TVCL = ... CL = TVCL*EXP(ETA(1)+ETA(2)*OCC1+ETA(3)*OCC2+ETA(3)*OCC3) ... $OMEGA BLOCK(1) 0.09 ; interindividual variability (IIV) $OMEGA BLOCK(1) 0.05 ; OCC1 $OMEGA BLOCK(1) SAME ; OCC2 $OMEGA BLOCK(1) SAME ; OCC3 You need to use the option SAME for OCC2,OCC3 as you want to preserve the distribution but sample ETAs for each occassion. There is an example in the Help Guide which might be useful. Regards, Joga Gobburu Pharmacometrics, CDER, FDA