Icotidine (also known as SKF 93319) was developed as histamine H1- and H2-receptor antagonist and possessed antinociception properties. Due to its antagonist activity, was suggested that compound could have therapeutic in some inflammatory skin diseases such as the urticarias and mastocytosis.

Berlafenone (previously known as GK 23 G), a sodium channel antagonist was studied as a class Ic antiarrhythmic agent, but development has been discontinued.

Ripazepam (CI 683 or pyrazapon) is a pyrazolodiazepine that has anxiolytic effects. It is related to certain benzodiazepines such as zolazepam. In animal studies, it showed anxiolytic effects without sedative or depressant effects. In rats, it did not elicit a tumorigenic potential. Although ripazepam was found significantly superior to placebo and was well tolerated in neurotic patients, it has never been marketed for clinical use.

Zatebradine is a bradycardic compound that blocks hyperpolarization-activated inward current (If) through cyclic nucleotide-gated cation (HCN) channels in sinoatrial node cells. Additionally, it can block voltage-gated outward K+ (IK) currents and related neuronal hyperpolarization-activated inward current (Ih) channels but exhibits little or no activity for L-type Ca2+ (ICa) currents. When assessed through telemetric ECG recording in mice, zatebradine reduced heart rate from 600 to 200 beats per minute with an ED50 value of 1.8 mg/kg and induced increasing arrhythmia at concentrations >10 mg/kg.

Berlafenone (previously known as GK 23 G), a sodium channel antagonist was studied as a class Ic antiarrhythmic agent, but development has been discontinued.

Icotidine (also known as SKF 93319) was developed as histamine H1- and H2-receptor antagonist and possessed antinociception properties. Due to its antagonist activity, was suggested that compound could have therapeutic in some inflammatory skin diseases such as the urticarias and mastocytosis.

Zatebradine is a bradycardic compound that blocks hyperpolarization-activated inward current (If) through cyclic nucleotide-gated cation (HCN) channels in sinoatrial node cells. Additionally, it can block voltage-gated outward K+ (IK) currents and related neuronal hyperpolarization-activated inward current (Ih) channels but exhibits little or no activity for L-type Ca2+ (ICa) currents. When assessed through telemetric ECG recording in mice, zatebradine reduced heart rate from 600 to 200 beats per minute with an ED50 value of 1.8 mg/kg and induced increasing arrhythmia at concentrations >10 mg/kg.