NONMEM Users Network Archive

Hosted by Cognigen

Re: Truncated Emax

From: Ignacio Ortega-FAES <IOrtega>
Date: Tue, 20 Dec 2011 08:02:41 +0100

Dear Francois,

Maybe this work can put some light to your question

Yassen A. Pharmacokinetic-Pharmacodynamic modeling of the antinociceptive
effect of buprenorphine and fentanyl in rats, role of receptor
equilibration kinetics JPET 2005; 313: 1136-1149.

Ignacio Ortega
Pharmacokinetics and Drug Metabolism Area
Research, Development and Innovation Department
Maximo Aguirre 14. 48940 Leioa

Francois Gaudreault <f_gaudreault11
Enviado por: owner-nmusers
19/12/2011 21:40


[NMusers] Truncated Emax

Dear NM users

I am currently developing a PK PD model for local anesthetics using a
sequential approach with ADVAN6. The PD model is a sigmoid Emax with an
effect compartment (Ce).

The intensity and duration of nerve blockade are monitored throughout the
perioperative period in patients using a quantitative pharmacodynamic
endpoint, i.e, the current perception threshold (CPT) REF: Can. J. Anesth, =

57 (S1) 2010). Briefly, CPT is evaluated before and after the
administration of the local anesthectic. Data are normalized by baseline
using the following equation :
(observed-baseline) / (max-baseline) *100 (%)

Here is the problem. The device only goes to a maximum of 10 mA. In some
patients, the real Emax is much higher. Any ideas on how handle a
truncated Emax ?

Thanks in advance

François Gaudreault, Ph.D. Candidate
Pharmacométrie / Pharmacometrics
Charger de cours / Lecturer
Faculté de pharmacie / Faculty of Pharmacy
Université de Montréal

Received on Tue Dec 20 2011 - 02:02:41 EST

The NONMEM Users Network is maintained by ICON plc. Requests to subscribe to the network should be sent to:

Once subscribed, you may contribute to the discussion by emailing: