Heptamidine is an effective Pentamidine-related inhibitor of the calcium-binding protein S100B (Kd: 6.9 μM). It selectively kills melanoma cells with S100B over those without S100B. It is a useful tool for the investigation of Myotonic dystrophy.
Mexiletine is a non-selective voltage-gated sodium channel blocker. It is a medicine in the class of IB anti-arrhythmic. Mexiletine may also be used in patients experiencing refractory pain and is effective to treat muscle stiffness resulting from myotonic dystrophy or non-dystrophic myotonias.