(The Kombé arrow-poison.) The seeds of Strophanthus hispidus De Candolle (Nat. Ord. Apocynaceae).

Composition and Properties

The active constituent of strophanthus is a glucoside, to which the name strophanthin has been given. It is contained in largest proportion in the seeds—from eight to ten per cent. The dose is 1/100 to 1/60 grain.

Strophanthin is crystallizable, slightly acid in reaction, freely soluble in water and in alcohol, but insoluble in ether, chloroform, and benzine.

Tinctura Strophanthi

Tincture of strophanthus. Strophanthus in No. 30 powder, 50 grm.; alcohol and water, of each a sufficient quantity to make up to 1,000 c. c. Dose: the initial quantity may range from one minim to ten minims, according to the manner of giving it. To maintain a uniform action, the initial dose may be larger, and the impression continued by small doses at short intervals.

An extract may be prepared by evaporation of the tincture, after the method of Rice. By a committee of the United States Pharmacopoeia Revision, experiments were made with the extract and tincture, and also with strophanthin, confirmatory of the observations of Rothziegel and Koralzewski, who had previously found that the glucoside was most active; but the physiological actions are the same.

Strophanthin can be administered subcutaneously by means of a solution of one grain to the ounce of chloroform water. Five minims contain about 1/100 grain. Such a solution will remain sterile for at least several days.

Actions and Uses

Strophanthus is bitter in taste, and, like many other bitters, promotes appetite and digestion. It is not irritating to the stomach, and apparently does not cause nausea. The property for which it is now introduced, however, is the more important one—that of cardiac tonic. Strophanthus slows the heart-beat, lengthens the interval between the contractions, and increases the energy of the cardiac muscular tissue. The arterioles are, to some extent, acted upon, and contract; but the rise of the blood-pressure is due more especially to the increased power of the cardiac contractions. The action of the heart is arrested in the diastole.

In consequence of the slower movement of the heart and the lessened caliber of the peripheral vessels, the quantity of blood distributed in a given time is relatively diminished; hence the consumption of oxygen is smaller, and the activity of the combustion-process correspondingly depressed. Strophantus is therefore an antipyretic within a quite limited range. Some diuretic power is also attributed to it.

On the foregoing physiological data the therapeutical properties are based. It has been prescribed with very distinct good effect in cases of mitral disease not compensated. Like digitalis, it lessens the ischaemia of the arteries, and increases the rate of movement of the blood in the veins; but, unlike digitalis, it does not much affect the caliber of the arterioles, and consequently does not so much increase the work of the heart by contracting them. If these valuable observations, which we owe to Prof. Fraser, be entirely confirmed by future investigations, strophantus will largely supersede digitalis in mitral lesions with its attendant disturbances.

Strophantus does not have a cumulative action, it is said; but that must depend on the frequency of administration, for if the doses are given at such a rate that the effects of one have not ceased before another is administered, clearly some accumulation of power must take place.