Ambasilide, a class III antiarrhythmic, has been shown to block multiple cardiac channels in a variety of animals including humans. Ambasilide is a potassium channel antagonist. Ambasilide has multichannel blocking properties including beta-adrenergic antagonism.

Clofilium is a quaternary ammonium compound that acts as potassium channel blocker. Clofilium is a class III agent. Clofilium increases atrial and ventricular effective refractory period without changing conduction time and, despite no apparent change in premature ventricular complex frequency, it can abolish the ability to induce ventricular tachycardia by programmed stimulation and is also well tolerated.

Dimethadione (5,5-dimethyl-2,4-oxazolidinedione) is the N-demethylated metabolite of the anticonvulsant trimethadione. Dimethadione is considered to be a blocker of T-type calcium channel. Dimethadione also inhibits a specific potassium channel (Ikr) in HERG-transfected cells. It exerts teratogenic effect especially congenital heart defects. Dimethadione can be used for the measurement of regional tissue pH using positron emission tomography.

NS-1643 is an activator of the human ether-a-go-go related gene (ERG1, KCNH2, hERG) KV11.1 channel. NS-1643 shows significantly increase both steady-state and peak tail currents of hERG channels but exhibits only a trivial effect on Kv4.3 and Kv1.5 channels. Causes a significant reduction in action potential duration in patch clamp assays in Xenopus oocytes, HEK293 cells, and guinea pig cardiomyocytes that can be reversed by the addition of E-4031, a specific blocker of hERG channels. Also shown to activate IKr channel in cardiomyocytes and increase post-repolarization refractory time thereby alleviating hyper-excitability and producing antiarrhythmic effects. NS-1643 can also restore IKr reduced by down-regulation of IKr expression. NS-1643 also activates the KV11.2 (ERG2, KCNH6) channel, but evokes a distinctly different response from that of KV11.1. NS-1643 is commonly used for Biochemicals applications.

Sophocarpine is a dehydrogenation derivative of the bis-quinolizidine alkaloid matrine. Sophocarpine is also an active component in sophora alkaloids, which possess a variety of pharmacological effects such as anti-inflammation, immunity regulation, antivirus, and anti-tumor actions. Sophocarpine is able to block HERG K+ channel. It is Na+ channel inward current inhibitor. It activates the AMPK signaling pathway and inhibits the TLR4-downstream pathway.

Verticine is a steroidal alkaloid compound extracted from the Fritillaria species of medicinal plants. Verticine was not only able to block the Nav1.7 ion channel but also preferably inhibited the Kv1.3 ion channel. It inhibits the production of inflammatory cytokines induced by LPS through blocking MAPKs and NF-κB signaling pathways. Verticine inhibited the hERG peak tail currents in a concentration dependent manner. Verticine exhibits anti-inflammatory, antitussive, antihypertensive and pain suppression properties.

Bufalin is a traditional oriental medicines, originally isolated from the Chinese toad venom. Bufalin is a cardiotonic steroid that has the potential to induce differentiation and apoptosis of tumor cells. Research on bufalin has so far mainly involved leukemia, prostate cancer, gastric cancer and liver cancer, and has been confined to in vitro studies. The bufadienolides bufalin and cinobufagin have been shown to induce apoptosis in a wide spectrum of cancer cell. Bufalin has being shown to be a potent small-molecule inhibitor of the steroid receptor coactivators SRC-3 and SRC-1. Bufalin is a component of Huachansu, a Chinese medicine that comes from dried toad venom from the skin glands of Bufo bufo gargarizans Cantor or B.melanotictus Schneider, has been used in the treatment of various cancers in China.

NS3623 is a human ether-a-go-go (hERG) KV11.1 potassium channel activator. It was shown that treatment of transgenic mouse model of sickle cell disease (SAD mice) with NS3623 improves erythrocyte hydration and diminishes sickling, probably by lowering of the Cl-conductance, which limits salt and concomitant water loss mediated by the Gardós channel, that makes NS3623 antisickling agent in vivo

Cyclovirobuxine D (CVB-D) is an active compound extracted from Buxus microphylla, which has been used of cardiac insufficiency and arrhythmias in China. The antiarrhythmic and proarrhythmic potential of this drug might be concerned with prolongation of action potential duration and QT interval. Human-ether-a-go-go-related gene (HERG) has an important role in the repolarization of the cardiac action potential. CVB-D inhibits HERG encoded potassium channels and this action might be a molecular mechanism for the previously reported APD prolongation and QT interval prolongation with this drug. Currently pharmacological studies on CVB-D have been conducted extensively for treatment of cancers. However, whether and how CVB-D affects other cellular processes and the tumorigenesis pathway of cancer cells is still largely unknown.