Voltage-gated sodium channels enable the translocation of sodium ions across cell membranes and play crucial roles in electrical signalling by initiating the action potential. In humans, sodium channel mutations give rise to a number of cardiovascular diseases, hence they are important targets for pharmaceutical drugs. The NavMs channel has been shown to be a good model for human channels, based on its high levels of sequence, structural and functional similarities to the human Nav1.5 isoform. Complexes of NavMs have been studied using crystallography, cryo-electron microscopy, and biophysical techniques including circular dichroism spectroscopy, bioinformatics, and molecular dynamics calculations, enabling idenfication of binding sites, molecular interactions, and the functional effects of both on-target and off-target drugs which bind to sodium channels. These studies can provide crucial infomation for the development of new pharmaceuticals and for the understanding of side-effects of currently-prescribed drugs.