Error (72) - Overflow

From: Rebecca Wrishko <wrishko@unixg.ubc.ca> Subject: Error (72) - Overflow Date: Mon, 15 Nov 1999 17:23:29 -0800 Fellow NONMEM Users, Recently, when altering the initial theta estimates I received the following error message: forrt1: error (72): error overflow. The error resulted when the initial theta estimates were set to: $THETA (0,0.5) (0,0.5) (0,1) (0,3) with the implementation of the following pk block; $PK TVCL=THETA(1)*WT CL=TVCL*(1+ETA(1)) TVV=THETA(2)*WT V=TVV*(1+ETA(2)) TVVSS=V+THETA(3)*WT VSS=TVVSS*(1+ETA(3)) However, when the initial theta estimates were set to $THETA (0,3) (0,5)(0,10) (0,3), no error message was given. Any suggestions to the cause and possible remedy would be greatly appreciated. Also, how does NONMEM generate the predicted serum concentrations at the times for which there is a corresponding event record? I have attempted using the final parameter one- and two-compartment estimates of CL and Vss, obtained from individual and population modeling routines, to calculate expected drug concentrations and do not derive the same values as those generated from the NONMEM execution. Thank you for your assistance. Rebecca Wrishko Division of Clinical Pharmacy Faculty of Pharmaceutical Sciences University of British Columbia Vancouver, British Columbia, Canada Email: wrishko@unixg.ubc.ca