Comparative effects of felodipine,nitrendipine and nifedipine in healthy subjects: concentration-effect relationships of racemic drugs and enantiomers |
| |
Authors: | P. A. Soons A. F. Cohen D. D. Breimer |
| |
Affiliation: | (1) Center for Bio-Pharmaceutical Sciences, Division of Pharmacology, University of Leiden, Leiden, The Netherlands;(2) Centre for Human Drug Research, Leiden, The Netherlands;(3) Present address: Department of Clinical Pharmacokinetics, Glaxo Group Research Ltd., Greenford, Middlesex, UK |
| |
Abstract: | Summary The effects of racemic (rac) felodipine, rac-nitrendipine and nifedipine (all 20 mg solution p.o.) on non-invasively measured blood pressure and heart rate were investigated in a randomised, double-blind, cross-over study in 12 normotensive, young, healthy males. Compared to baseline values, heart rate increased more after rac-felodipine treatment (+47% at maximum) than rac-nitrendipine (+40%) and nifedipine (+38%); only small and variable changes in blood pressure were observed with any of the drugs. The baseline-corrected area under the heart rate-time curve up to 4 h after the administration of rac-felodipine was 197% and 180% larger than after nifedipine and rac-nitrendipine treatment, respectively. The effects on heart rate could be fitted individually to a sigmoidal Emax-model without hysteresis for all drugs under investigation. The relative potencies of the unbound drugs for their indirect effects on heart rate were 1:7:43 for nifedipine, rac-nitrendipine and rac-felodipine, respectively. The active (S)-enantiomers of felodipine and nitrendipine appeared to be 9-and 60-times as potent as nifedipine in this respect, assuming no (inter)activity of the (R)-enantiomers. Individual and mean changes in blood pressure were small, they were not related to plasma concentrations, and did not differ between treatments.Pharmacokinetic data obtained in this study are reported in the accompanying paper |
| |
Keywords: | Felodipine Nitrendipine Nifedipine enantiomers blood pressure heart rate concentration-effect relationship healthy volunteers |
本文献已被 SpringerLink 等数据库收录! |
|