THEORY OF TREATMENT OF COUGH 289 



_ Many authors simply make two divisions of expectorants, class- 

 ing all except the sedative expectorants as stimulant, and following 

 with the statement that the sedative expectorants increase secretions 

 and the stimulant expectorants check the secretions. The terms 

 sedative and stimulant as applied to expectorants do not have any 

 reference to their effect upon the secretions but to their action upon 

 the organism as a whole. 



The depressant expectorants (sedatives) promote the secretions, 

 render them less viscid, and consequently more easily removed. In 

 addition to this many of them are soothing to the irritated mucous 

 membrane. Most of them will be recognized as emetics, and prob- 

 ably they owe much of their power of increasing secretions to their 

 nauseating properties. They are used in much smaller doses as 

 expectorants than as emetics. In man and those animals which 

 vomit an active emetic will often aid the expulsion of tenaceous 

 mucus (croup in children). Sedative expectorants are indicated 

 in acute bronchitis or in the early stages of other diseases in which 

 there is a hard dry cough, considerable irritation and little or no 

 discharge. In these conditions as in all other active inflammations 

 there is considerable swelling and irritation. The sedative expec- 

 torants lower arterial pressure, lessen the blood stipply and increase 

 the secretions which have been partly or entirely suspended. 



Those classed as stimulant expectorants are largely eliminated 

 through the bronchial mucous inembrane and are thought to stimulate 

 the mucosa, increase blood pressure and increase secretions. They 

 are believed to produce this action either by stimulation of the 

 relaxed mucosa or by exerting an antiseptic action upon the secre- 

 tions. They are indicated in relaxed conditions of the mucosa, as 

 in the second stage of acute diseases of the respiratory system or 

 in chronic bronchitis. The alkalies are especially useful to lessen 

 the viscidity of the mucus, render it more fluid and more easily 

 expelled. Stimulating expectorants are not indicated in acute condi- 

 tions because to stimulate an already inflamed mucous membrane 

 would do more harm than good. 



With the exception of atropine and acids, those classified as 

 diminishing secretion belong to the group of antiseptics and volatile 

 oils and depend upon their elimination through the bronchial mucous 

 membrane for action. Theoretically, at least, they are indicated m 

 cases of purulent discharge from the respiratory tract but whether 

 they act as expectorants or are eliminated in the secretions m suHi- 

 cient amounts to stimulate the mucous membrane or act as antiseptics 

 has not been proven. Clinically they appear of considerable impor- 



^^ Theory of the Treatment of Cough. Cough may be de- 

 fined as a reflex act involving the respiratory center, resulting m a 

 violent and forceful expulsion of air from the lungs. It consists ol 



