Pildralazine is a hydralazinelike antihypertensive vasodilator containing a free hydrazine group. Potency of the compound was shown to be from 6 to 10 times greater than that of hydralazine although, from a qualitative point of view, the two drugs act similarly. Pildralazine was shown to be inactive on nictitating membrane contractions induced by sympathetic stimulation or by adrenaline injection into the lingual artery. However, it antagonized the vascular effects of adrenaline, angiotensin and vasopressin in pithed rats and spinal cats. Pildralazine significantly inhibited the onset of severe hypertension in rats; the combination of pildralazine with moderately effective doses of propranolol or dihydrochlorothiazide completely prevented the blood pressure increase. Whereas a lack of carcinogenic activity has been reported for pildralazine in 1983, a report published in Germany in 1985 states the drug to be mutagenic with auxotrophic mutants of S.Typhimurium and E.coli.

Diprafenone closely resembles propafenone in both structure and function. It is beta adrenoceptor antagonists and sodium channel antagonists. Diprafenone is highly protein bound in plasma. It has demonstrated efficacy against supraventricular and ventricular arrhythmias in clinical trials. Diprafenone produced first-degree atrioventricular block in 6/20 patients tested with coronary artery disease and sustained ventricular tachycardia. Intravenous application of diprafenone significantly increased atrioventricular nodal conduction time as well as the effective refractory periods of the right ventricle and the accessory pathway in both the antegrade and retrograde directions in 15 patients with the Wolff-Parkinson-White syndrome and symptomatic supraventricular tachycardia.

Hexadiline was used as an internal standard in liquid chromatography-mass spectrometry.

Leptacline is the respiratory analeptic.

Dopropidil is an antianginal calcium ion modulating agent, possessing intracellular calcium antagonist activity and anti-ischemic effects in several predictive animal models. Dopropidil had similar vasorelaxant potency as bepridil in the rabbit aorta depolarized by K(+), but was less potent than verapamil, nifedipine, and diltiazem in this respect. Dopropidil has an unusual pharmacological profile, which includes both antiarrhythmic and anti-atherosclerotic properties. In vitro studies show that dopropidil inhibits both smooth and cardiac muscle contractions induced by activation of voltage operated channels, and inhibits the “slow” inward calcium current in the latter tissue, suggesting that dopropidil blocks membrane calcium ion channels. Dopropidil-induced inhibition of collagen and thrombin-induced platelet aggregation at higher concentrations also suggests actions other than calcium channel blockade since platelets lack voltage operated channels. Dopropidil also reduces fatty streak formation in the aorta of cholesterol fed rabbits, an action which may be related to the demonstrated antioxidant properties of this compound. Long-term toxicity studies in rats and dogs showed only mild toxic signs, notably a decrease in food consumption, slight sedation, and some vomiting in the latter species. Dopropidil had been in phase II clinical trials for the treatment of angina pectoris and arrhythmias. However, these studies were discontinued.

Bendazol (or dibazol), a vasodilator that used in Russia. This drug is indicated for the treatment of arterial hypertension, hypertensive crisis, spasms of internal organs (stomach ulcer, intestinal spasms), and diseases of the nervous system: residual effects of poliomyelitis. Bendazol lowers blood pressure by reducing cardiac output and expansion of peripheral vessels.

Prifuroline is a benzofuran derivative patented by French pharmaceutical company Laboratoires Jacques Logeais S. A. As an antiarrhythmic agent. After intravenous administration to pentobarbital-anesthetized dogs, Prifuroline produced a significant dose-related decrease in heart rate and in sinus node recovery time. Prifuroline dose-dependently antagonizes the arrhythmogenic action of aconitine in rats when administered either intravenously or intraduodenally. Prifuroline also diminishes ventricular susceptibility to electrical stimulation in open-chest rats; its effect is comparable to that of disopyramide and amiodarone at the same dose levels. Prifuroline was also able to restore sinus rhythm in guinea-pigs after intracardiac conduction blockade with acetylcholine, although being devoid of anticholinergic activity.

Emakalim (EMD 56431) is ATP-sensitive potassium channel opener. It exerts vasorelaxant and cardioprotective effects. Emakalim was being developed for the treatment of hypertension and ischaemic heart disorders.