Re: Non-influential Eta

Mahesh, If you are using NONMEM VI then you are OK because the bug has been fixed in the distributed source code. If you are using NONMEM V and the source code has been patched as recommended by Icon/Globomax/NONMEM Project group then the bug will not affect you. You only need to worry if you (or your IT support) have not paid attention to the announcements made about NONMEM bugs and how to fix them. The simplest and most reliable way to keep your system up to date is to use NMQUAL for installation. http://www.metruminstitute.org/downloads/nmqual/ Nick Samtani, Mahesh [PRDUS] wrote: > Dear NMusers, > > I am trying to sequentially model the PD of a drug that has a simple inhibitory Emax effect. There is a clear placebo response from the control group and placebo effect goes away once patients stop taking their placebo pills (Hence the TY code below). Both drug & placebo effect (decrease from baseline) are bigger in patients with higher baseline. I want the etas on placebo and drug parameters (C1 and SMAX) to be correlated with baseline (BS) eta, which is done using the Block Band matrix. I think this problem may have the non-influential eta bug (eta on Smax for placebo subjects???). When I run the code below, the model runs quite well. How do I know if I have been bit by the bug and how can I fix it. > > Kindly advice...Mahesh > > $SUBR ADVAN4 TRANS4 > > $PK > CALLFL = -2 > > ; PK PARAMETERS DRUG SPECIFIC VALUES REMOVED > KA = # > CL = # > Q = # > V3 = # > V2 = # > F1 = # > F2 = 1-# > D2 = # > ALAG1 = # > > L1 = THETA(1)*EXP(ETA(1)) > SC50 = THETA(2)*EXP(ETA(2)) > > C1 = THETA(3)*EXP(ETA(3)) DURA = THETA(4) > > BS = THETA(5)*EXP(ETA(4)) > SMAX = THETA(6)*EXP(ETA(5)) > > $ERROR > > ; BS IS THE BASELINE > ; TY IS THE PLACEBO RESPONSE > ; HFN IS HILL FUNCTION FOR DRUG EFFECT > > IF (TIME.LE.DURA) THEN > TY=C1/L1*(1-EXP(-L1*TIME)) > ELSE > TY=C1/L1*(1-EXP(-L1*DURA))*EXP(-L1*(TIME-DURA)) > ENDIF > > HFN=(SMAX*F)/(F+SC50) > > EFF=BS-TY-HFN > IPRE = -5 > IF (EFF.GT.0) IPRE=LOG(EFF) > Y=IPRE+ERR(1) > > $OMEGA ; DRUG SPECIFIC VALUES REMOVED > # > # > > $OMEGA BLOCK(3) ; DRUG SPECIFIC VALUES REMOVED > > # # # 0 # # -- Nick Holford, Dept Pharmacology & Clinical Pharmacology University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New Zealand [EMAIL PROTECTED] tel:+64(9)373-7599x86730 fax:+64(9)373-7090 www.health.auckland.ac.nz/pharmacology/staff/nholford