3. Therapeutic Application

Digitalis has been known as a medicine from the earlier modern times; though the ancients were probably altogether ignorant of its powers. it was recommended in scrofula by Van Helmont and Boerhaave, and is said to have held a place in the London Pharmacopoeia in 1121, though afterwards discarded. it never, however, was in general use; and attracted little attention from the profession until the appearance of Dr. Withering's monograph in 1715, recommending it as a most valuable remedy in dropsy. its important sedative properties were soon developed; and, both as a diuretic and a sedative, it now takes a rank inferior only to a few of our most esteemed medicines.

Digitalis is indicated, as a sedative, whenever inordinate action of the heart is to be reduced, or high nervous excitement to be allayed, provided that time be allowed for the safe employment of the remedy. it is contraindicated in great feebleness of the heart's actions, and prostrated states of nervous power; and hence is hazardous near the close of exhausting diseases, though it might seem to be called for by frequency of the pulse and nervous disturbance. Nor, in consequence of its slow action, can it be relied on in cases, in which an immediate and energetic impression upon the nervous centres, or upon the heart is required. it is also contraindicated when there is high vascular irritation or inflammation of the stomach.

Inflammation. This affection would appear to offer obvious indications for the use of digitalis, both from the circulatory and nervous excitement which enters into its constitution; and the sedative powers of the medicine had no sooner been determined, than attention was strongly directed to it as a means of cure in this affection. it was, indeed, hoped that it might prove a substitute for the lancet, and thus cure the disease without debilitating the patient. Experience, however, soon disappointed these beautiful expectations; and digitalis was found not to be a reliable remedy in inflammation. The reason of this is obvious. it is not solely a reduction of the circulation, or of nervous excitement, that is wanted in this pathological condition. There is an indication, also, for altering the character of the blood. This is done by bleeding, the antimonials, and other arterial sedatives; and this is what digitalis fails to do. Another objection to relying upon it, in the phlegmasiae, is the frequent necessity for a promptness of treatment to which digitalis is unsuited, because hazardous, if used in large doses with a view to immediate effect. While we are cautiously administering the remedy, and watching for the effects of its repeated doses, the time for efficient interference often passes, and its influence may thus come too late. Nevertheless, it is sometimes very serviceable in inflammatory diseases, as an adjuvant to other measures, or even as a substitute for the lancet, when this could not have been employed, or can be employed no longer. Whenever, in these diseases, there is an indication for reducing the pulse, and the blood is too much impoverished to admit of further change, but yet not so depraved as to be unfit for the support of the functions, as it is in the typhoid state, then digitalis may be given, and will not unfrequently prove useful. Another condition often attendant on inflammation calls specially for this remedy. I allude to serous effusion, of which digitalis powerfully promotes the absorption, partly perhaps by depressing the pulse, but chiefly by its diuretic action. Unless there is frequency of pulse to be subdued, with a condition contraindicating the loss of blood, or serous effusion which it is desirable to remove by absorption, this medicine is of little use in the phlegmasiae; when these two conditions are conjoined, it is often highly serviceable.

In pneumonia, it has been recommended either in one large dose, so as to bring the system promptly under its depressing influence, or in very minute doses repeated every hour, till the same effect is produced; but we have, I think, safer and much more reliable means for accomplishing the same object; and I do not, therefore, think the treatment advisable. it has been particularly recommended in this disease in connection with kermes mineral.

But in pleurisy and pericarditis, with copious effusion, especially in their advanced stage or chronic condition, digitalis is often very useful, particularly in connection with calomel. Squill often also answers the same purpose, as regards the absorption of the liquid, but it is less suitable than digitalis, when there is a frequent pulse requiring reduction. in cases where the choice between digitalis and squill is doubtful, the two remedies may be given conjointly, and both often with calomel.

In meningeal inflammation, especially in children, the same indication often exists; much of the danger here being attributable to the pressure of the effused serum upon the brain.

Acute rheumatism often calls for digitalis, in that anemic condition in which bleeding is inappropriate, and especially when conjoined with pericardial or endocardial inflammation. Under these circumstances, it is all-important to quiet the heart, the movements of which are acting as a perpetual source of irritation to the inflamed membranes. it may here in general be usefully associated with calomel, and almost always with nitre.

Scrofulous inflammation is often attended with a frequent pulse, which it is generally not permitted to reduce by bleeding, and in which even the antimonials may be contraindicated, either by their tendency to nauseate, or their effect in impairing the blood. Digitalis may be usefully employed in these cases, in connection with the appropriate tonics and alteratives. it has already been stated, that scrofula was the complaint in which digitalis was first used.

Fevers. in the febrile state, not less than in the inflammatory, there would seem to be an indication for the sedative effects of digitalis on the heart and nervous system; but experience has not pronounced more decidedly in its favour, in the idiopathic fevers, than in the phlegmasiae. Something more than a reduction of the pulse is necessary here also; and, in the highest stage of excitement, digitalis would generally fail to produce even this effect, unless in hazardous doses. When, however, the violence of the disease has abated, while the pulse remains very frequent, digitalis may sometimes be usefully employed, if there be no typhous complication present. it is peculiarly applicable, combined with tonics, to those cases of imperfect convalescence from fever in which the pulse continues obstinately frequent.