The bark of Aspidosperma quebracho bianco Schlechtendal (Nat. Ord. Apocynaceae).

Preparations

Tincture.—One part of quebracho to five parts of alcohol. Dose, τη v— 3 j. (Not official.)

Extractum Aspidospermatis Fluidum

Fluid extract of aspidosperma. Dose, τη j to τη x or more.

The fluid extract is a more eligible preparation than the alkaloid aspidospermine, which represents in part only the powers of the drug.

Composition

Quebracho seems peculiarly rich in alkaloids, but it is doubtful whether any one represents in its entirety the physiological powers of the bark itself. The most important are aspidospermine, discovered by Fraude in 1878, and quebrachine, separated by Hesse in the following year. Hesse describes several other active constituents or alkaloids, but the two just mentioned are the most important.

Adulterations

Soon after the first specimens were sent to Europe, the sudden demand which sprang up induced sophistication, and quebracho-wood and quebracho Colorado were substituted for the genuine. This substitution proved the less important, since these preparations acted in a similar manner, and were only weaker (Pen-zoldt). The early physiological investigations must, therefore, be interpreted by the light of this difference in the action of the several substances comprehended in the term quebracho.

Physiological Actions

Quebracho has the stomachal effects of the bitters in general: it promotes appetite and increases the digestive powers. The alkaloids diffuse promptly into the blood. The action of the heart is lowered; the pulse in the normal state is less frequent; at first, the tone of the artery is higher and the blood-pressure is raised, but as the action is continued, especially from lethal doses in animals, the force of the circulation declines and the pressure falls. The respiration is also slowed, and the sense of need of air is less imperative. The hurry of circulation and of respiration, and the feeling of oppression induced by active exercise, are modified by quebracho. Picot-Berthold studied these actions on his own person. Ascertaining first the rate of increase of the respiratory movements and of the circulation induced by active exercise of a definite amount, he next determined the influence of the remedy on these functions when the same amount of exercise had been taken. While without quebracho his pulse and respiration rose respectively to 42 and 94, under the action of the medicament they were 30 and 80. Not only was the rate of movement lessened, but the accompanying distress for want of air was decidedly ameliorated.

Guttmann, who has made an elaborate study of aspidospermine, finds that in both cold- and warm-blooded animals it is an active poison of the respiratory and circulatory apparatus. In cold-blooded animals the respiratory actions are most pronounced, and death is produced by the effect of the poison on the respiratory center. Slowing of the heart's action proceeds pari passu with the diminution of the respiratory energy, and the cessation of the heart's movements is finally due to the impression of the poison on the intra-cardiac motor ganglia. In warm-blooded animals (cats) the influence of the poison on the heart is primary. The slowing of the pulse is not due to any effect which it has on the vagi, but to the paralyzing action which it exerts on the cardiac motor ganglia. With the slowing of the heart the temperature declines, and, with the diminution of respiration, dyspnoea comes on. Then the accumulation of carbonic acid in the blood induces stupor, and in animals convulsions. The reflex function is lowered in cold- but not in warm-blooded animals; sensibility is unaffected in the latter, but motor paralysis finally occurs in both classes. Death is due to paralysis of the heart.

Therapy

The applications of quebracho in the treatment of disease were originally empirical, but they are clearly deducible from its physiological actions. It has long been known as a fever-medicine and as a remedy for dyspnoea, in the province of Santiago, Chili, where it was first obtained by Dr. Schickendanz. It has been used as a stomachic tonic, like the bitters in general, but more especially like cinchona, to increase the appetite and digestion in atonic dyspepsia. It is, however, chiefly important as a remedy for dyspnoea.

Picot, Skoda, Krauth, Penzoldt, and many others, have used it in various instances of difficult breathing, with remarkable palliation. In emphysema, spasmodic asthma, uraemic asthma, in spasmodic cough, chronic bronchitis, with asthmatic breathing, it has afforded very considerable relief. It has appeared to be much less useful, if not injurious, in the dyspnoea from valvular disease of the heart, and has had no effect in the dyspnoea of old subjects due to atheroma of the vessels. Krauth, however, has used it with advantage in the dyspnoea due to hypertrophy of the heart and in the difficulty of breathing in a case of albuminuria consecutive to scarlatina. The relief to dyspnoea in all cases, Penzoldt thinks, is referable to the increased consumption of oxygen by the blood, but a more rational explanation would seem to be the action on the respiratory center, and the diminution in the sense of need of air.