ADMINISTRATION OF PURGATIVES 235 



1. Believe constipation. In acute simple constipation a cathar- 

 tic or enema is always indicated. The vegetable laxatives are gen- 

 erally employed in chronic constipation if dietetic measures fail. 



2. Remove irritants from the intestinal tract. Purgatives are 

 indicated to remove irritants either in case of poisoning where the 

 poison has escaped from the stomach or in early stages of acute 

 diarrhea. 



3. Promote absorption. In this case the hydrogogues, and es- 

 pecially the salines, are indicated in case of cardiac and renal drop- 

 sies. They remove fluid from the blood and promote the absorption 

 of lymph from the tissues by depleting the blood. They do not 

 often prove serviceable in serous effiisions of an inflammatory 

 nature as in pericarditis and pleurisy. 



4. Remove waste products from the hlood, as in uremia, puer- 

 peral eclampsia or azoturia to remove' toxic material. 



5. Relieve cerebral congestion. In this case the hydrogogue 

 purgatives are indicated, since they tend to draw the blood to the 

 bowels and to deplete the brain. They are also useful in cerebral 

 hemorrhages, as they tend to prevent further extravasation of 

 blood. 



6. Lower temperature in fever. Both purgatives and diuretics 

 lower temperature in fever in some unknown manner. 



7. Deplete the gastroduodenal mucosa, where the congested and 

 swollen mucosa obstructs the outflow of bile resulting in jaundice. 

 In this condition the salines and especially the sodium salts are most 

 ■efficient carthartics. 



8. Relieve hemorrhoids or piles. In this case the milder cathar- 

 tics such as sulphur, senna, compound licorice powder, etc., should 

 be used. 



Administration of Purgatives. Purgatives are most fre- 

 quently given per os, although some are administered per rectum, 

 subcutaneously and intravenously. The vegetable preparations are 

 usually given as a pill or solution, although powders are occasionally 

 prescribed. The oils are given in a drench and the salines in solu- 

 tion. 



Classification. Cathartics have been grouped according to 

 their chemistry, method of causing action, and according to their 

 intensity of action and the character of feces obtained; but, since 

 the intensity of action and character of action depend largely upon 

 the dose, a classification so based must necessarily be imperfect. 

 The following classes have been defined: laxatives, purgatives, dras- 

 tics and hydrogogues. 



Laxatives. These are the least irritating and least active of the 

 cathartics. They produce stools quite normal in appearance and 

 consistence. This group includes many foods, such as bran, 

 molasses, and fruit. Most important drugs of this group are : 



