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Korean J Pain 2004; 17(2): 119-124

Published online December 1, 2004 https://doi.org/10.3344/kjp.2004.17.2.119

Copyright © The Korean Pain Society.

Effects of Intrathecal Flecainide for Pain Behavior in Formalin Test and Hemodynamics in Rat

Heon Chang Park, Chang Mo Kim, Jeong Il Choi, Seong Wook Jeong, Hong Buem Bae, Geong Duck Park, Myung Ha Yoon

Department of Anesthesiology and Pain Medicine, Medical School, Chonnam National University, Gwangju, Korea.

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background: The antinociceptive activity of drugs with a sodium channel blocker is an anti-arrhythmic agent belonging to the Ic class. Although the antinociceptive effects of flecainide have been demonstrated in a few animal pain models and clinical trials, its role in nociceptive transmission at the spinal level has not been evaluated. The purpose of this study was to evaluate the effects of intrathecal flecainide on nociception and hemodynamics. Methods: Flecainide was administered via an intrathecal catheter. The formalin test was used as an animal pain model, in which the pain was induced by a subcutaneous injection of formalin solution (5%, 50mul) into the rats' hind paw. The blood pressure and heart rate were measured using an intra-arterial catheter in the tail artery. Results: Intrathecal flecainide administered prior to the formalin injection reduced the pain behavior in a dose-dependent fashion during both phases 1 and 2. In contrast, the formalin injection administered after the intrathecally-administered flecainide did not affect the pain behavior in phase 2 at the highest dose. In addition, the intrathecal flecainide produces no significant effect on the resting blood pressure or heart rate. Conclusions: Intrathecal flecainide attenuated the pain behavior when administered before, but not after the formalin injection, and caused no significant hemodynamic changes. (Korean J Pain 2004; 17: 119 124)

Keywords: antinociception, flecainide, formalin test, hemodynamics, rat, spinal cord