A textbook of pharmacology and therapeutics, or, The action of drugs in health and disease / by Arthur R. Cushny.

  • Arthur Robertson Cushny
Date:
1903
Catalogue details

Licence: Public Domain Mark

Credit: A textbook of pharmacology and therapeutics, or, The action of drugs in health and disease / by Arthur R. Cushny. Source: Wellcome Collection.

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    A great deal of time and energy has been devoted to an attempt to bring the effects in the organism of certain metals (notably the alka¬ lies) into relation with their atomic weights, their valency, and other properties, but no results are to be expected from these researches, so long as their ordinary chemical reactions can only be formulated to a limited extent and imperfectly from these considerations. In particu¬ lar, it seems of little interest to determine their exact relative toxicity, since there is no question that they do not all act on the same organs, and if one act on the brain and another on the heart, one by its specific affinity for an organ and another by inducing physical changes in the fluids of the body, these differences are sufficient to nullify any rela¬ tion which they may bear to each other in regard to the exact fatal dose. As has been stated, it may be inferred with some probability that any substance belonging to certain wide chemical groups will in¬ duce symptoms in the organism resembling in general characters those of the other members provided always that it does not contain some radicle which renders it inactive, or gives it a more powerful action in some other direction. But the details of its action can be ascertained only by actual experiment, exactly as the details of its chemical be¬ havior can be known only by performing the necessary reactions; and as there is no prospect of explaining the latter from its constitution at the present time, there is still less hope that much advance will be made in the near future in formulating the laws governing the details of its pharmacological effects. CONDITIONS MODIFYING THE EFFECTS OF DRUGS. The effects of drugs on the living organism are subject to some modi¬ fications in certain individuals, and under some conditions, which it is of importance that the physician should recognize, as the dose has to be altered when they are present. One of these is the Size and Weight. If the same amount of a poison be distributed through the tissues of a large individual as of a small one, less is contained in any given organ of the former and less effect is therefore observed. This has been ascertained chiefly in animal experiment, in which the effects of drugs can be estimated much more exactly than in man, but it un¬ doubtedly holds good for human beings also. Very large individ¬ uals, then, require a somewhat larger dose than ordinary persons, while in treating individuals of small stature, the dose has to be reduced. The Age of the patient has also to be taken into account in prescrib¬ ing. Children ought to receive much smaller doses than adults. The more powerful action of drugs in children is due in part to their smaller size, in part to the more active growth of certain tissues and to the less complete development of others, such as the central nervous system. The dose for a child is generally calculated according to Young’s formula, in which a fraction obtained by dividing the age by the age + 12, is taken as the proportion of the adult dose required. Thus for a
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