Pincainide is a new beta-amino anilide with local anesthetic properties. It has been shown to be 3 times more potent than lidocaine as a local anaesthetic on desheathed frog sciatic nerve. It was found to be effective against arrhythmias induced in guinea-pigs by ouabain infusion or by administration of adrenaline and chloroform. Pincainide not only inhibited the influx of Ca 2+ and increased 45Ca efflux, thus reducing the contractile responses induced in rat aorta by noradrenaline and high K +, but it also inhibited other effects related to the noradrenaline-induced release of intracellular Ca 2+ stores. Further studies, however, must be performed in experimental models of arrhythmias before the effectiveness of pincainide as an antiarrhythmic drug can be established.

S-aranidipine or (S)-MPC-1304 is an enantiomer of MPC-1304 (methyl 2-oxopropyl 1,4-dihydro-2,6-di-methyl-4-(2-nitrophenyl)-3,5-pyridinedicarboxylate), a calcium entry blocker. The Ca2+ entry blocking activity of the (S) enantiomer of MPC-1304 was approximately 150 times greater than that of its (R) enantiomer. Likewise, the antihypertensive effect of the (S) enantiomer was twice as great as that of MPC-1304 (racemate) in conscious spontaneously hypertensive rats, while the (R) enantiomer was ineffective. Thus, most of the pharmacological activity of MPC-1304 resides in its (S) configuration.

R-aranidipine or (R)-MPC-1304 is an enantiomer of MPC-1304 (methyl 2-oxopropyl 1,4-dihydro-2,6-di-methyl-4-(2-nitrophenyl)-3,5-pyridinedicarboxylate), a calcium entry blocker. R-aranidipine is inactive enantiomer.

Phenthiazamine was developed by Sekizawa et al. as a centrally acting anesthetic for fish. The time required to reduce the positive ganglionic potential in the sympathetic ganglion by phenthiazamine was prolonged in the presence of higher concentrations of Ca2+. The Ca2+-dependent action potential of guinea-pig ureter was reduced by this compound, whereas it did not affect the Na+-dependent action potential.

Fenoverine is a potent musculotropic, the anti-spasmodic agent that restores smooth muscle motility and relieves the distressing symptoms associated with irritable bowel syndrome (IBS) and primary dysmenorrhea. Fenoverine is a non-anticholinergic phenothiazine derivative that may also inhibit calcium channel currents. Fenoverine primarily affects the gastrointestinal tract, bile duct, and female genital organs. Fenoverine has been repeatedly implicated in the occurrence of rhabdomyolysis, a potentially fatal adverse effect, in France. Thes drug has been therefore unavailable in France since December 1995 but commonly used in the treatment of gastrointestinal spasmodic disorders in Taiwan.

Suloctidil is considered to be calcium antagonist. In addition to its vascular antispasmodic activity, suloctidil affects blood platelets and enhances brain energy metabolism. Suloctidil was being evaluated in many clinical trials for use in dementia and thrombotic disorders. Suloctidil induces hepatotoxicity.

Phenthiazamine was developed by Sekizawa et al. as a centrally acting anesthetic for fish. The time required to reduce the positive ganglionic potential in the sympathetic ganglion by phenthiazamine was prolonged in the presence of higher concentrations of Ca2+. The Ca2+-dependent action potential of guinea-pig ureter was reduced by this compound, whereas it did not affect the Na+-dependent action potential.