This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
Other evils arise from the abuse of these medicines. Allowing that they act equally on the whole system, and equally elevate all the functions, they of course promote digestion, increase the quantity and stimulant quality of the blood, augment the nutrition of all the organs, and thus put the system into a state in which, from its universal exaltation, a slight irregularity may cause the excess of excitement to fall, with an overwhelming force, on some important organ, and thus seriously endanger health, if not life, before the compensating provision of impaired excitability has had time to come into play. But supposing, as generally happens, that the tonic operates with especial force on some one organ, or series of organs, the constant excitement sustained in it attracts an excess of blood and of nervous influence, which may in the end occasion inflammation. When the stimulation is powerful, the resulting inflammation may be acute; but, as resulting from tonics, it is generally chronic.
Thus, the abuse of the medicine may lead in the end to general debility, and at the same time chronic inflammation of particular organs; a complication which it is difficult to treat, and which can, in fact, be treated successfully only by withdrawing the cause, either abruptly or gradually, and trusting to the recuperative powers of the system.
The principles above stated are strongly illustrated by the results of the abuse of the Portland powder, formerly much employed in the treatment of gout. This powder consisted of a combination of vegetable bitters and aromatics, and was to be taken continuously for two years, at the end of which time a permanent cure might be expected. Dr. Cullen states that the cases of nine or ten persons had come under his knowledge, who took the remedy the required length of time, having previously been subject to regular attacks of inflammatory gout yearly, or twice a year. After a longer or shorter continuance of the remedy, they had missed the paroxysms, and, at the end of the two years, were entirely free from them, and had no attack afterwards for the remainder of their lives. But in every instance their health was impaired; they were much troubled with dyspeptic and nervous disorder, and low-ness of spirits; and, in less than a year from the completion of the course, without exception, they began to exhibit dropsical symptoms, which gradually increased, in the form of hydrothorax or ascites with anasarca, and in two or at most three years proved fatal. (Culleris Mat. Med.) It is not difficult to explain the result in these cases. The constant use of the stimulant impaired and finally exhausted the excitability of the system; debility with anaemia ensued; and with these were probably combined chronic visceral inflammation, especially of the stomach, liver, and heart, resulting from the sustained irritation of the medicine, and the superadded irritation of the gout, invited from an external to an internal seat.
It is inferrible from the above course of reasoning, the correctness of which has been abundantly confirmed by experience, that tonics should never be given in a state of sound health with the hope of increasing strength, nor for too great a length of time even in diseased conditions, in which they may have been originally indicated, for fear of inducing secondary debility and perhaps chronic inflammation.
But, nevertheless, these remedies are of great value in various conditions of depressed and torpid function and debility. It may be said that here also, as well as in health, the principles above developed are applicable; and that the ultimate effect ought to be, by an impairment of the excitability, still further to depress and weaken the system. It can, however, be shown that this is not a legitimate deduction.
1. It has been stated that the characteristic office of tonics is moderately and somewhat durably to increase the vital actions. Their first direct effect, therefore, in depressed function, is to obviate this condition. As strength consists in the normal state of the ultimate organic constituents of the tissues, which can be sustained only by a due degree of all the vital processes which contribute to the nutrition or maiutenance of parts, and tonics have the property of stimulating these processes, it follows that, when they are deficient, and debility has ensued as a result, tonics may prove not only stimulant but positively strengthening, provided the depressing causes do not outlast the excitability of the part or parts affected. Let us apply this principle.
In numerous diseases, there is a depressed condition of function, with or without positive debility, which depends upon a cause either essentially temporary or removable. Such a condition exists, for example, in low states of fever of a typhoid character, in which a depressing poison is probably acting upon the system, and in the suppurative stage of inflammation, and in gangrene, in which the strength is exhausted by copious discharge, or prostrated by the sedative influence of the mortification. In either of these cases, life may be in imminent danger; but, as the operation of the cause is temporary, if the vital functions can be sustained until this ceases or is removed, the patient may be saved Tonics may afford the support requisite for this purpose. They excite the depressed functions, and strengthen by due nutrition the debilitated structures; and, long before the excitability, through which they operate, has had time to suffer materially from the stimulus, the cause ceases, and the system is left in a condition in which it can repair itself.
2. We not unfrequently meet with cases of depression and debility, continuing after the cause has ceased. The system, or a part of it is, as it were, left paralyzed. It seems as though a habit of insufficient action had been established, which the inherent force of the system could not throw off. Living, like dead matter, has a sort of vis inertiae, which disposes it to continue in any condition in which it may have compulsorily continued for a considerable time. Under these circumstances, a little gentle stimulus serves to rouse it out of its torpor; and once again fairly in action, it will go on without further aid. As a watch stopped in the winding, and continuing quiescent, will resume its accustomed motions with a little shaking; so the system, reduced by disease, and remaining torpid after the disease has ceased, will react with a slight excitation, and enter again into its ordinary round of action. Tonics are often sufficient to give the requisite impulse. Hence, in part at least, their use in the torpor of system, or that of a particular organ, so common in convalescence from acute disease.