caa a22 4500 477056792 CHVBK 20180405111348.0 cr unu---uuuuu 170330e19961001xx s 000 0 eng 10.1007/s002280050177 doi (NATIONALLICENCE)springer-10.1007/s002280050177 Concentration-effect relationship of the positive chronotropic and hypokalaemic effects of fenoterol in healthy women of childbearing age [Elektronische Daten] [T. Bouillon, I. Meineke, R. Port, R. Hildebrandt, K. Günther, U. Gundert-Remy] Objective: To analyse fenoterol-induced tachycardia and hypokalaemia, the most important and most frequent adverse effects of tocolytic therapy with β2-adrenoceptor agonists in females of childbearing age. Methods: The study was performed as a double blind, randomised, placebo controlled, cross over trial. Seven healthy women aged 22-38 y, received intravenous infusions of fenoterol at 3 different rates within the therapeutic range for tocolysis (0.5,1.0, and 2.0 μg⋅min−1) and placebo. The time courses of the plasma concentrations of fenoterol and potassium, and the heart rate were analysed with mixed effects pharmacokinetic-pharmacodynamic (PKPD) modeling using NONMEM. Results: The plasma concentration-time course followed a linear two compartment model. Fenoterol-induced tachycardia was described by a linear concentration-effect model with baseline. The estimated baseline and slope parameters were 78 beats⋅min−1 and 0.032 beats⋅min−1⋅μg−1⋅l, respectively. Fenoterol-induced hypokalaemia could be described by a physiological indirect response model including feedback; the Estimated basal plasma potassium concentration was 3.93 mmol⋅l−1 and the slope factor for the fenoterol-induced relative increase in the efflux of potassium from the extracellular space was 6.22*10−4 ng⋅l−1. Conclusion: The estimated population parameters permitted calculation of the expected time course of tachycardia and hypokalaemia in women after the initiation of tocolysis with fenoterol over the clinically relevant concentration range, and prediction of its variability. Based on simulation, our model predicted that a continous infusion of 2.0 μg⋅min−1 (highest rate examined) would increase heart rate to 113 beats⋅min−1 at steady state and lower the plasma potassium concentration to 2.77 mmol⋅l−1 1.5 h after beginning the infusion. Thereafter, the plasma potassium concentration would slowly return to normal. Springer-Verlag Berlin Heidelberg, 1996 Key words Fenoterol nationallicence Tachycardia nationallicence Hypokalaemia nationallicence β2-adrenoceptor agonist nationallicence NONMEM nationallicence pharmacokinetic/pharmacodynamic modeling nationallicence Bouillon T. Department of Clinical Pharmacology, University of Göttingen, Göttingen, Germany, DE aut Meineke I. Department of Clinical Pharmacology, University of Göttingen, Göttingen, Germany, DE aut Port R. German Cancer Research Institute, Heidelberg, Germany, DE aut Hildebrandt R. Department of Gynecology and Obstetrics, Freie Universität Berlin, Berlin, Germany, DE aut Günther K. Department of Experimental and Clinical Pharmacology, Bundesgesundheitsamt, Berlin, Germany, DE aut Gundert-Remy U. Department of Clinical Pharmacology, University of Göttingen, Göttingen, Germany, DE aut https://doi.org/10.1007/s002280050177 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s002280050177 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bouillon T. Department of Clinical Pharmacology, University of Göttingen, Göttingen, Germany, DE aut NATIONALLICENCE 700 1- Meineke I. Department of Clinical Pharmacology, University of Göttingen, Göttingen, Germany, DE aut NATIONALLICENCE 700 1- Port R. German Cancer Research Institute, Heidelberg, Germany, DE aut NATIONALLICENCE 700 1- Hildebrandt R. Department of Gynecology and Obstetrics, Freie Universität Berlin, Berlin, Germany, DE aut NATIONALLICENCE 700 1- Günther K. Department of Experimental and Clinical Pharmacology, Bundesgesundheitsamt, Berlin, Germany, DE aut NATIONALLICENCE 700 1- Gundert-Remy U. Department of Clinical Pharmacology, University of Göttingen, Göttingen, Germany, DE aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer