Re: Re: [NMUSERS] Questions on fitting pediatric PK data using NONMEM

Winnie, If you are serious about modelling PK in children then I suggest you become familiar with some basic concepts of scaling for size and maturational changes with age (see Anderson & Holford 2008). These can be readily implemented in NONMEM. In preparing your data the important thing is to record the actual dose -- not the dose scaled per kg or per sq m. You should also try to get body weight and height and post-menstrual age if you are dealing with neonates. Nick Anderson BJ, Holford NH. Mechanism-Based Concepts of Size and Maturity in Pharmacokinetics. Annu Rev Pharmacol Toxicol. 2008;48:303-32. [EMAIL PROTECTED] wrote: > Hello all > > I work with small number of pediatric inpatients with few samples from each > patient of various age and weights. > > I am a novice in using NONMEM. > > I would appreciate advice on fitting the data using various dose inputs - > should we normalize > the dose and other parameters by weights ? Since the range is large > in my datasets, the variability could be quite large without using /kg > dosing. > > Example > 24 patients with different age and size (paediatrics) on Cyclosporin IV > infusion over 2 hours > with 5 levels taken at similar times post 1st (and only dose). Although > dose at 1.5mg/kg, > the actual amount of dose given for each patient varies. Looking at the raw > data and log conc vs time graphs, > it appeared 2-compartment would be suitable. However, Volume of > distributions and clearances > varies with units without normalization to body weight (kg) or body size > (BSA). > > Any thoughts or suggestions would be much appreciated. > Thank You! > > Winnie > > Winnie Seto, BScPhm, PharmD, MSc, ACPR, R.Ph. > Therapeutic Drug Monitoring Coordinator & > Critical Care Unit Pharmacist > The Hospital for Sick Children > 555 University Avenue > Toronto, Ontario > Canada M5G 1X8 > phone: 416-813-6236 > fax: 416-813-5880 > > This is a medical communication. This e-mail message is for the sole use of > the intended recipient(s) and may contain privileged and confidential > information. Any unauthorized review, use, disclosure or distribution is > prohibited. If you are not the intended recipient, please contact the > author by reply email and destroy all original and copies of this email > message. -- 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