Aperients

Aperients are substances which are employed to cause intestinal evacuations. Many articles of food, such as oatmeal, brown bread, and bran biscuits, and fruits such as figs, prunes, and strawberries, are used for this purpose; but the term is usually applied to denote certain medicines which act upon the intestines and cause them to expel their contents. Although considerable progress has been made in recent years in the investigation of the action of various drugs upon the intestines, we are as yet unable to give a final classification to them. For practical purposes, however, we may classify aperients as follows: (1) laxatives and (2) purgatives—(a) cathartic and (b) drastic. (1) Laxatives are substances which only slightly increase intestinal action. They act without causing any irritation or griping. The chief examples of this class are manna, magnesia, olive oil, sulphur, and castor oil in small doses. (2) Purgatives—(a) Cathartics are substances which quicken or increase the evacuations from the intestines, and in their action may cause griping. Examples of this class are aloes, castor oil in large doses, rhubarb, senna, and various species of rhamnus; (b) drastics are substances which are prompt, powerful, and effective in operation. Colocynth, croton oil, elaterium, gamboge, jalap, podophyllin, and scammony belong to this class. Besides the substances already enumerated, we must mention the saline aperients—e.g. sulphates of potassium, sodium, and magnesium, tartrates of potassium and sodium, phosphate of sodium, and citrate of magnesium. Of the above drugs, bitartrate of potassium, elaterium, and gamboge act as hydrogogues (Gr. hudōr, 'water,' and ago, 'I drive away'), as they tend to remove water from the system; and aloes, eunonymin, iridin, mercurial preparations (blue pill, calomel), podophyllin, and rhubarb, act as cholagogues (Gr. cholē, 'bile'), as they increase the evacuation of bile. Purgatives may be said to act in three ways—(1) by increasing the peristaltic action of the intestines; (2) by causing an increase of the secretion from the intestinal mucous membrane; and (3) by preventing the absorption of the fluids of the intestines. Purgatives have various uses, for they not only remove the contents of the intestines, but also prevent the accumulation of feces in them, and the irritation such accumulation causes. They are useful in cases of dropsy, to remove excessive fluids from the body. In fever they lower the temperature, and they are of use in lowering the blood pressure in certain diseases. Lastly, in cases of hernia, aneurysm, and some other disorders, they are beneficial in preventing difficulty in the act of defecation. Although the use of aperients is of undoubted benefit, yet their abuse is much to be deprecated, as to employ them habitually or promiscuously may produce serious results. There are also used as aperients many Mineral Waters (q.v.).