Azamethonium (known in Europe as pendiomid), a substance with the ganglia-blocking effect that was used in Europe to treat patients with acute pulmonary embolism. Information about the nowadays application of this drug is not available.

Traxoprodil (CP-101,606) is a potent, selective N-Methyl-D-aspartate (NMDA) receptor (NR2B subunit) antagonist under development by Pfizer for its potential as a neuroprotectant in head injury and neurodegenerative disease. It is in phase II trials in the US and in phase I in Japan for the potential treatment of head injury, such as, Depressive Disorder, Major and Parkinson's Disease. CP-101,606 does not protect against glutamate-induced neurotoxicity in cultured cerebellar neurons, up to a dose of 10 uM. These results are consistent with CP-101,606 being a potent NMDA antagonist, selective for the type of NMDA receptor associated with the hippocampus. Some further investigation revealed that CP-101,606 was associated with a dose-related dissociation and amnesia. These results support the hypothesis that glutamate antagonists may be useful antidyskinetic agents. However, future studies will have to determine if the benefits of dyskinesia suppression can be achieved without adverse cognitive effects.

Risotilide is a Class III antiarrhythmic agent that inhibits the voltage-dependent potassium channel. Risotilide prolongs cardiac action potentials and refractory periods. It was shown to reduce ventricular vulnerability in a study on arrhythmogenic effects of left ventricular hypertrophy (LVH) in the intact heart in cats. Phase I and II trials have been conducted, but development of this drug has been discontinued.

Edonentan (BMS 207940) is a highly selective biphenylsulfonamide endothelin A receptor antagonist. (11)C- and (18)F-labeled analogs of edonentan were evaluated of novel PET radioligands for imaging the endothelin-A receptor. Edonentan was in clinical trials for the treatment of heart failure however its development has been discontinued.

Guanoxyfen sulfate is an antidepressant, antihypertensive. Guanoxyfen sulfate is an inhibitor of vasoconstrictor responses to sympathetic nerve stimulation. It could potentiate the actions of adrenaline and noradrenaline. It also could increase the blood glucose concentration and decrease the appetite.

Emilium is an antiarrhythmic agent and cardiac depressant.

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.

Drobuline is a potent cardiac depressant (anti-arrhythmic) agent, which has been found to be effective against ventricular arrhythmias in dogs. This compound is a racemic mixture having a single center of optical activity. The two isomers of drobuline were found to be equally potent in converting cardiac arrhythmias in dogs after intravenous administration. The major route of biotransformation of drobuline in the dog was shown to be conjugation with glucuronic acid.

Sematilide (CK-1752) was developed as a novel class III antiarrhythmic agent for the arrhythmia treatment. Sematilide blocks the inward rectifier potassium channel (IK1). The further development of the drug was discontinued.

Suricainide (also known as AHR 10718) is an aminoalkylurea derivative patented by A. H. Robins Co., Inc. as an antiarrhythmic agent. Suricainide induces a use-dependent decrease in Vmax and significantly decreased Purkinje fiber conduction velocity and action potential duration. Suricainide had no effect on slow response action potentials induced by isoproterenol but ventricular muscle action potentials were significantly prolonged by Suricainide. Suricainide significantly decreased normal automaticity, catecholamine-enhanced automaticity, and abnormal automaticity induced by barium or myocardial infarction. In preclinical modes, Suricainide suppresses the aconitine-induced canine atrial arrhythmia.