Back to the Top
The following message was posted to: PharmPK
Hi,
Does anybody here used pk/pd link model for delayed response at
steady state? Theoretically, keo only refer to non steady state?
Looking forward to advise
Thanks
Xia
Back to the Top
The following message was posted to: PharmPK
Xia,
I am guessing that what you call the "pk/pd link model for delayed
response" refers to the effect compartment model (Sheiner et al. 1979;
Holford & Sheiner 1981). There is no theory to say that 'keo only
refer[s] to non-steady state'. The effect compartment model can be used
to predict effects at steady state. If the driving PK model
concentrations are constant at steady state (e.g. by giving a constant
rate input) then the effect compartment concentration is usually
assumed to be the same as the PK model concentration but this is an
unusual situation. More commonly intermittent dosing is used which may
reach a steady state (i.e. rate in = rate out over the dosing
interval). In this case the PK model concs will still vary after each
dose and the effect compartment concs will also vary.
Nick
Sheiner LB, Stanski DR, Vozeh S, Miller RD, Ham J. Simultaneous
modeling of pharmacokinetics and pharmacodynamics: application to
D-tubocurarine. Clinical Pharmacology and Therapeutics
1979;25(3):358-371
Holford NHG, Sheiner LB. Understanding the dose-effect relationship:
Clinical application of pharmacokinetic-pharmacodynamic models.
Clinical Pharmacokinetics 1981;6:429-453.
--
Nick Holford, Dept Pharmacology & Clinical Pharmacology
University of Auckland, 85 Park Rd, Private Bag 92019, Auckland, New
Zealand
email:n.holford.aaa.auckland.ac.nz tel:+64(9)373-7599x86730 fax:373-7556
http://www.health.auckland.ac.nz/pharmacology/staff/nholford/
PharmPK Discussion List Archive Index page
Copyright 1995-2010 David W. A. Bourne (david@boomer.org)