Ingleby-Talecki, Lindsey;
van Dijkman, Sven C;
Oosterholt, Sean P;
Della Pasqua, Oscar;
Winter, Christina;
Cunnington, Marianne;
Rebar, Linda;
... Chaudhary, Khuram W; + view all
(2022)
Cardiac sodium channel inhibition by lamotrigine: in vitro characterization and clinical implications.
Clinical and Translational Science
, 15
(8)
pp. 1978-1989.
10.1111/cts.13311.
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Abstract
Lamotrigine, approved for use as an antiseizure medication (ASM) as well as the treatment of bipolar disorder, inhibits sodium channels in the brain to reduce repetitive neuronal firing and pathological release of glutamate. The shared homology of sodium channels and lack of selectivity associated with channel blocking agents can cause slowing of cardiac conduction and increased proarrhythmic potential. The Vaughan-Williams classification system differentiates sodium channel blockers using biophysical properties of binding. As such, Class Ib inhibitors including mexiletine do not slow cardiac conduction as measured by the electrocardiogram (ECG), at therapeutically relevant exposure. Our goal was to characterize the biophysical properties of NaV 1.5 block and to support the observed clinical safety of lamotrigine. We used HEK-293 cells stably expressing the hNaV 1.5 channel and voltage clamp electrophysiology to quantify the potency (IC50 ) against peak and late channel current, on-/off-rate binding kinetics, voltage-dependence and tonic block of the cardiac sodium channel by lamotrigine; and compared to clinically relevant Class Ia (quinidine), Ib (mexiletine) and Ic (flecainide) inhibitors. Lamotrigine blocked peak and late NaV 1.5 current at therapeutically relevant exposure, with rapid kinetics and biophysical properties similar to the Class Ib inhibitor mexiletine. However, no clinically meaningful prolongation in QRS or PR interval was observed in healthy subjects in a new analysis of a previously reported thorough QT clinical trial (SCA104648). In conclusion, the weak NaV 1.5 block and rapid kinetics do not translate into clinically relevant conduction slowing at therapeutic exposure and support the clinical safety of lamotrigine in patients suffering from epilepsy and bipolar disorder.
| Type: | Article |
|---|---|
| Title: | Cardiac sodium channel inhibition by lamotrigine: in vitro characterization and clinical implications |
| Location: | United States |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1111/cts.13311 |
| Publisher version: | https://doi.org/10.1111/cts.13311 |
| Language: | English |
| Additional information: | © 2022 GSK. Clinical and Translational Science published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/). |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > UCL School of Pharmacy UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > UCL School of Pharmacy > Pharmacology |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10161292 |
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