Cardiovascular Agent

a medicinal preparation used in the treatment of heart failure and disorders of vascular tension. Cardiovascular agents include cardiac glycosides, vasodilators, and vasoconstrictors. Most cardiac glycosides and digitalis glycosides are similar in structure and activity; they differ primarily in side effects, the speed and duration of activity, and the tendency toward cumulation.

Cardiovascular agents increase the force and reduce the frequency of cardiac contractions; they also improve metabolism in cardiac muscular tissue. They are used under medical supervision in cases of heart failure and abnormal cardiac rhythm (for example, in treating the tachyarrhythmic form of atrial fibrillation and the supraventricular form of paroxysmal tachycardia).

The most effective cardiovascular agents are digitalis powder, tincture, and extract, as well as such secondary digitalis glycosides as digitoxin and digoxin. Also effective are preparations containing a combination of glycosides (for example, lanatosides) and preparations of Strophantus, Adonis (for example, adonisid), Convallaria (for example, corglykon), and Erisimum (for example, erisimin).

Vasodilators relax the smooth musculature of the coronary and peripheral arteries and reduce vasospasms. For example, an attack of angina pectoris is arrested by the use of such quick-acting vasodilators as nitroglycerin and amyl nitrite. Attacks are prevented during chronic coronary insufficiency by the administration of Euphyllin, papaverine, and vasodilators with long-term action, such as pentacrythrityl tetranitrate and sustac.

Many preparations, for example, chromonar (Intensain), not only strengthen coronary blood flow but also improve metabolic processes in the heart, reduce the oxygen requirement of the myocardium, and strengthen collateral circulation. Propranolol (Inderal), a β-adrenergic blocking agent, simultaneously improves metabolic processes in the heart and reduces the contractile activity of the myocardium. Pyridinol carbamate (anginine) improves microcirculation.

Medicinal treatments for injuries to peripheral arteries include the application of vasodilators and substances that stimulate the formation of collaterals and improve microcirculation. Preparations that excite the vasomotor center, for example, cardiamin, corazole, and camphor, are prescribed in cases of vascular insufficiency accompanied by hypotonia. In cases of acute vascular insufficiency (collapse), quick-acting vasoconstrictors, such as noradrenaline, phenylephrine hydrochloride, and angiotensin amide, are administered.