RE: covariance step
Hello
You should increase the upper boundaries. Also you might try using
allometric models while fixing some of the parameters, if data is
limited.
Atul
Venkatesh Atul Bhattaram
Pharmacometrics
Office of Clinical Pharmacology
US Food and Drug Administration
"The contents of this message are mine personally and do not necessarily
reflect any position of the Government or the Food and Drug
Administration."
Quoted reply history
-----Original Message-----
From: [email protected] [mailto:[email protected]]
On Behalf Of Varsha Mehta
Sent: Thursday, July 16, 2009 1:21 PM
To: [email protected]; [email protected]
Subject: [NMusers] covariance step
Dear NONMEM users:
I have a data set for 30 infants where I am running a 2 COMPT PK model.
I got the following error message for the covariance step. I need some
help with trying to fix this error. Any suggestions? should I increase
the upper boundries of initial estimates?
MINIMIZATION SUCCESSFUL
NO. OF FUNCTION EVALUATIONS USED: 289
NO. OF SIG. DIGITS IN FINAL EST.: 3.0
0PARAMETER ESTIMATE IS NEAR ITS BOUNDARY
THIS MUST BE ADDRESSED BEFORE THE COVARIANCE STEP CAN BE IMPLEMENTED
any help is appreciated.
Thanks
Varsha Mehta, MS(CRDSA), Pharm.D., FCCP
Clinical Associate Professor
Pharmacy, Pediatrics and Communicable Diseases
Clinical Pharmacist Neonatal Critical Care
University of Michigan
(O) 734-936-8985
(F) 734-936-6946
[email protected]
**********************************************************
Electronic Mail is not secure, may not be read every day, and should not
be used for urgent or sensitive issues