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 FAES FARMA Maximo Aguirre 14. 48940 Leioa Spain Francois Gaudreault <[email protected]> Enviado por: [email protected] 19/12/2011 21:40 Para <[email protected]> cc Asunto [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
