■ib GENERAL ACTION OF DRUGS 



salicylic acid), expelling or inhibiting the formation of toxins or in 

 some way improving digestion (nitrohydrochloric acid). The conditions 

 in which they act most favorably are indigestion and constipation, with 

 or without icterus and clay colored stools. Such conditions were formerly 

 thought to be due primarily to disordered liver or "biliousness," but the 

 cases amenable to treatment really arise in the beginning from functional 

 disorder of the stomach or intestines. 



General Uses of Purgatives. 



1. To empty the bowels. — In this way are removed fecal accumula- 

 tions and poisonous matters resulting from bacterial infection, and from 

 fermentative and putrefactive changes in the intestinal contents in indi- 

 gestion. Foreign bodies, bile, pathological discharges and intestinal para- 

 sites are also expelled. 



Peristaltic action is quickened in chronic constipation, while spas- 

 modic and painful conditions (colic) are relieved by ridding the bowels 

 of the source of irritation causing the trouble. 



2. To remove fluid from the body. — This effect is more marked 

 after the use of concentrated solutions of saline purgatives and other 

 hydragogues. Concentration of the blood and resulting absorption of 

 dropsies of renal and cardiac origin, or inflammatory effusions, may be 

 accomplished by these agents. 



3. To revulse. — ^That'is, to cause dilatation of the blood vessels in 

 the intestinal walls and so withdraw blood from remotely congested areas, 

 as in meningitis. The drastics are appropriate for this service. Pain 

 and nervous phenomena in other regions are sometimes benefited by the 

 counter-irritant action of drastic cathartics. 



4. To deplete.- — Cathartics, particularly concentrated saline solu- 

 tions, deplete the body both locally and generally by withdrawal of serum 

 from the blood vessels. Purgatives tend to combat inflammation (anti- 

 phlogistic action) in this way by lowering blood tension whila they also 

 favor reduction of a febrile temperature by removal of toxins. Local 

 depletion by salines is especially indicated in diarrhea and dysentery, in 

 hemorrhoids (sulphur, liquid petrolatum), and in the first stages of acute 

 inflammation of the digestive tract. Plethora and obesity are often 

 treated by a depletive method with cathartics. 



5. To eliminate. — Deleterious material in the blood resulting from 

 renal insufficiency, and probably from infection in acute diseases, may be 

 eliminated to a considerable extent by purgatives. So also may the hemic 

 sources of puerperal eclampsia, uremia, lymphangitis and hemoglobinemia 

 be excreted. 



Contra-indications. — These refer rather to the special agent than to 

 any disorder, for there is scarcely a condition in which some cathartic is 

 not permissible. 



Drastics are inadmissible under the following circumstances: in 

 catarrhal conditions of the respiratory and digestive tracts, intestinal 

 hemorrhage, collapse, anemia, hernia, prolapse of rectum, metritis, 

 nephritis, pregnancy, general debility, and in wounds of and operations 

 upon the pelvic or abdominal viscera. 



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