Therapeutical agents defined.

(Part I: A study of drugs)

Other tomes: Felter - Petersen

HAEMATICS restore the quality of the blood to normal condition. They exert a direct influence on the composition of the blood: e.g., preparations of iron, of manganese, cod-liver oil, etc.

ALKALIES act, in the concentrated form, as caustics (escharotics), but when diluted, as antacids. Dilute alkalies, if given before meals, however, will stimulate the production of the acid gastric juice. The carbonates of potassa and soda and the bicarbonates, also preparations of the alkaline earths, such as lime-water and mixtures of magnesium carbonate, are good examples. Some of the salts of the alkalies have a remote antacid effect, becoming decomposed in the blood and excreted in the urine, which they render less acid.

ACIDS.—These have an action opposite to that of the alkalies. When much diluted, they are administered for the purpose of checking hyperacidity of the stomach, by stimulating the production of the alkaline pancreatic juice and checking the acid gastric juice. Examples: Dilute hydrochloric acid, phosphoric acid.

DIGESTANTS.—Agents which effect solution (digestion) of food in the alimentary canal. Examples: Pepsin, pancreatin, trypsin, papain, etc.

ANTIPYRETICS.—Agents which reduce the temperature of the body, either by reducing the circulation or diminishing tissue change, or metabolism, or favoring the loss of heat through radiation, conduction, etc. Examples: Quinine, aconite, antipyrine, antimony, etc.

ALTERATIVES.—A term used to designate a class of agents which alter the course of morbid conditions, modifying the nutritive processes while promoting waste, by stimulating secretion, absorption, and the elimination of morbid deposits; especially used in the chronic diseases of the skin. Employed in the treatment of phthisis, syphilis, gout, neuralgia, asthma, etc. Examples: Arsenious acid, mercury, iodine and the iodides, sarsaparilla, guaiac, colchicum, stillingia, etc.

CEREBRAL EXCITANTS.—Agents which increase the functional activity of the cerebrum, without causing any subsequent depression of brain function. Examples: Camphor, valerian, caffeine, cannabis (in small doses), etc.

CEREBRAL DEPRESSANTS have an opposite effect to the preceding, lessening brain activity. Some of the drugs of this class are employed as hypnotics or as analgesics.

NARCOTICS.—Agents which lessen the sensibility to pain and cause sleep. A narcotic will abolish pain, while an anodyne will frequently merely overcome wakefulness. Examples: Opium, cannabis indica, belladonna, humulus, etc.

HYPNOTICS.—Agents which induce sleep and will often abolish pain and cause neither deliriant nor narcotic effects. Examples: Chloral, sulphonal, trional, the bromides, etc.

ANALGESICS.—Agents which relieve pain by their effect upon the sensory centers; the term is synonymous with anodynes. The general anodynes, which taken internally, affect the whole organism; local anodynes affect the part to which they are applied. Examples: Opium, belladonna, hyoscyamus, aconite, antipyrine, acetanilid, aspirin, chloral hydrate, etc.

ANAESTHETICS.—Agents which suspend consciousness and temporarily destroy sensation. The local anaesthetics affect only the part to which they are applied. Examples: Ether, chloroform, nitrous oxide, etc. Local anaesthetics: Cocaine, carbolic acid, ether spray, etc.

MOTOR EXCITANTS.—Agents which increase the functional activity of the spinal cord and the motor apparatus, invigorating the action of the heart and lungs. Examples: Nux vomica, strychnine, etc.

MOTOR DEPRESSANTS have an opposite effect to the motor excitants, lowering the functional activity of the spinal cord and motor apparatus. Examples: Alcohol, opium, aconite, conium, belladonna, etc.

ANTISPASMODICS.—Agents acting on the nervous system in various ways. They prevent or allay irregular action or spasm of voluntary and involuntary muscles. This is accomplished frequently by a sedative influence upon the nerve centers, while a few others exert their influence by stimulating the nerve centers employed to relieve spasms. Examples: Alcohol, ether, valerian, camphor, asafoetida, musk, the bromides, hydrocyanic acid, etc.

TONICS.—Agents which increase the vigor and tone of the system by improving the appetite, favoring digestion and assimilation, and adding strength to the circulatory system. Examples: Gentian, columbo, quinine, etc.

ANTIPERIODICS.—Agents which prevent or check the return of diseases which recur periodically, possibly by a toxic action upon the microbes in the blood, which are supposed to cause the disease; but little is known of their mode of action. The typical antiperiodic, quinine, has, however, a decided effect upon the heart and brain, as well as other parts of the nervous system.

CARDIAC STIMULANTS, as the name implies, are agents which increase the heart's action, the force and frequency of the pulse. Examples:Ether, alcohol, atropine, sparteine, nitroglycerine, etc.

CARDIAC SEDATIVES allay and control palpitation and overaction of the heart. Examples: Aconite, veratrum viride, digitalis, antimony, etc.

VASCULAR STIMULANTS.—Agents which dilate the peripheral vessels and increase the peripheral circulation. Members of this class also strengthen the heart's action, and are advantageously employed in debilitated conditions of the central organs of the circulation. Examples: Alcohol, preparations of ammonia, caffeine, digitalis, strophanthus, epinefrin, etc.

VASCULAR SEDATIVES.—Agents which lessen the capillary circulation and raise the blood pressure by stimulating the vasomotor center or its mechanism and the walls of the vessels. Examples: Ergot, digitalis, opium, salts of iron, etc.

DIURETICS.—Agents which increase the secretion of urine, acting either directly upon the secreting cells of the kidneys or by raising the general or local arterial tension. Employed in acute congestion and inflammation of the kidneys and in dropsies. Examples: Squill, scoparius, triticum, and organic salts of the alkalies.

RENAL DEPRESSANTS.—Agents which lower the activity of the renal cells, thereby lessening the urinary secretion. Examples: Morphine, quinine, ergot, etc.

VESICAL TONICS AND SEDATIVES.—Agents acting upon the bladder, in the one case increasing the tone of the muscular fibers and in the other lessening the irritability of that organ. Examples: Tonics-strychnine, cantharis, belladonna, etc.; sedatives-opium, buchu, uva ursi, pareira, etc.

RENAL SEDATIVES.—Agents which exert a sedative action upon the whole urinary tract. Examples: Copaiba, cubebs, etc.

DIAPHORETICS AND SUDORIFICS.—Agents which increase the action of the skin and promote perspiration. Examples: Dover's powder, jaborandi, camphor, sweet spirits of niter, etc,

ANHIDROTICS.—Agents which check perspiration. Examples: Acid camphoric, atropine, zinc salts, acids, alum, etc.

ANTILITHICS.—Agents used to prevent the formation of insoluble concretions or to dissolve concretions when formed in the ducts. Examples: Salts of lithia, potassium, benzoic acid, etc.

EXPECTORANTS.—Agents which are employed to facilitate the expulsion of bronchial secretions and to modify the character of these when abnormal. Examples: Ammonium chloride, the aromatic balsams, squill, licorice, senega, etc.

PULMONARY SEDATIVES.—Agents which allay the irritability of the respiratory center and the nerves of the lungs and bronchial tubes. Examples: Belladonna, opium, hyoscyamus, hydrocyanic acid, etc.

ERRHINES AND STERNUTATORIES.—The latter are agents which affect locally the nasal mucous membrane, producing sneezing; the former produce an increase of nasal secretion and discharge. They- also indirectly stimulate the vasomotor centers and at the same time excite the respiratory centers. Examples: Ipecacuanha, sanguinaria, veratrine, etc.

SIALAGOGUES.—Agents which promote the secretion and flow of saliva from the salivary glands. Examples: Pyrethrum, mezereum, the mercurials and antimonials, etc.

EMETICS.—Agents which cause vomiting, acting directly upon the nerves of the stomach or acting through the blood upon the vomiting center, or by reflex irritation of the vomiting center. Examples: Mustard, zinc sulphate, apomorphine, ipecacuanha, tartar emetic, etc.

PURGATIVES produce evacuation of the contents of the intestinal canal by increasing secretion along the tract, by exciting peristaltic action, etc. Examples: Podophyllum, colocynth, jalap, croton oil, magnesium sulphate, etc.

ASTRINGENTS.—Agents which produce contraction of muscular fiber, which coagulate albumen and lessen secretion from mucous membranes, arresting discharges. Examples: Tannic and gallic acids, alum, lead acetate, persulphate of iron, etc.

STOMACHICS.—Agents which increase the appetite and promote gastric digestion. They also check fermentation and dispel accumulation of flatus. Examples: Peppermint, cardamom, ginger, capsicum, etc.

HEPATIC STIMULANTS (Cholagogues).—Agents which excite the liver and increase the functional activity of that organ so that the amount of bile is augmented, etc. Hepatic stimulants increase the activity of the liver-cells, while cholagogues remove the bile from the duodenum. Examples: Podophyllum, aloes, jalap, colocynth, mercurous chloride, etc.

HEPATIC DEPRESSANTS.—Agents which reduce the functional activity of the liver, having the opposite effect of the foregoing, that of diminishing the formation of the bile, urea, and glycogen. Examples: Opium, quinine, arsenic, antimony, etc.

ECBOLICS, OR OXYTOCICS.—Agents which stimulate the pregnant uterus and produce contraction of that organ, either by direct irritation of the muscles of the womb, or indirectly by affecting the uterine center of the cord. Examples: Ergot, cotton-root bark, savin, cimicifuga, etc.

EMMENAGOGUES.—Agents which stimulate the uterine muscular fibers and restore the normal menstrual function. Examples: Ergot, apiol, iron, etc.

APHRODISIACS.—Agents used to excite the function of the genital organs when they are morbidly depressed. Examples: Phosphorus, zinc phosphide, salts of iron, gold, or arsenic, etc.

ANAPHRODISIACS.—Agents which diminish the sexual desire. Examples: The bromides, camphor, etc.

MYDRIATICS.—Agents which cause dilatation of the pupil; used to temporarily destroy accommodation by causing paralysis of the ciliary muscle. Examples: Atropine and homatropine.

MYOTICS.—Agents acting in a manner contrary to that of the above, producing contraction of the pupil by stimulating the circular muscular fibers of the iris and at the same time contracting the ciliary muscle. Examples: Pilocarpine, eserine, etc.

IRRITANTS.—Agents which are applied locally to the skin to produce certain effects, as rubefacients (simply reddening the skin); epispastics (blistering); pustulants (causing blebs in which is found pus); escharotics, or caustics (actually destroying the tissue). Examples: Mustard (rubefacient); cantharides (epispastic); croton oil (pustulant); caustic potassa, carbolic acid, and strong mineral acids (escharotics).

LOCAL SEDATIVES.—Agents which diminish irritation in the part to which applied, relieving local inflammation. Examples: Acetate of lead, opium, belladonna, etc.

DEMULCENTS.—Bland remedies used to allay and mechanically protect inflamed surfaces. They are used also internally for this purpose, as in acute inflammation of the alimentary canal. Examples: Mucilages of acacia, flaxseed, Iceland and Irish moss, elm, etc.

EMOLLIENTS resemble the above; are used externally to soften and soothe the irritated and abraded skin. Examples: Lard, olive oil, cacaobutter, etc.

ANTISEPTICS.—Agents which arrest putrefaction, either by preventing the growth of micro-organisms causing putrefactive decomposition or by destroying these micro-organisms. Examples: Carbolic acid, corrosive sublimate, etc.

DISINFECTANTS.—Some authorities limit the use of this term to those agents which destroy the micro-organisms. The terms antiseptic and disinfectant are frequently used interchangeably. Examples: Corrosive sublimate, carbolic acid, iodoform, zinc chloride, eucalyptol, etc.

ANTIZYMOTICS.—A term applied to agents which arrest fermentation. Examples: See above.

ANTHELMINTICS.—Agents which destroy such parasitic worms as infest the alimentary canal. Taeniafuges destroy tape-worms; vermifuges expel these intestinal parasites. Examples: Santonin, spigelia, chenopodium, etc. Taeniafuges: Filix mas, pelletierin, cusso, etc.

ANTIPARASITICS.—Agents which destroy those parasites which infest the human body externally. Examples: Mercurial preparations, chrysarobin, carbolic acid, cocculus, etc.


Thus far we have only very briefly called attention to therapeutical and physiological action of drugs, giving but a few examples. We will temporarily leave the further consideration of this, and for the time refer to the therapeutical agents themselves. (Sayre, in order to be comprehensive, briefly defines all chemicals, synthetic or organic, then used in medicine. I have deleted much of this as the primary value and the preponderance of the text is plant and animal drugs,—MM)

A Manual of Organic Materia Medica and Pharmacognosy, 1917, was written by Lucius E. Sayre, B.S. Ph. M.