288 DRUGS ACTING UPON RESPIRATORY SYSTEM 



the respiratory tract as in pneumonia, where it may be combined 

 with strychnine, and serve as a valuable stimulant to respiration, and 

 at the same time prevent effusion and vasomotor and cardiac depres- 

 sion. Atropine is also a valuable vasomotor, cardiac, and respira- 

 tory stimulant in cases of poisoning by depressant drugs (ether, 

 chloroform, aconite, eserine, arecoline, pilocarpine). 



Respiratory Depressants. These are agents that depress the 

 respiratory center. The most important drugs of this group are: 



Opium Bromides 



Chloral Hyoseine 



There are many other drugs that depress the center and produce 

 asphyxia in toxic doses but they are never used in medicine for 

 that purpose. The chief indications for these agents as pulmonary 

 depressants are in diseases of the respiratory tract to allay cough. 

 Most of them have been discussed in other places. 



EXPECTORANTS 



Expectorants are agents that increase, decrease or modify the 

 secretions of the air passages. The exact manner of their action 

 is unknown although most of them probably act reflexly from an 

 irritant (nauseant) action in the stomach. This has been demon- 

 strated to be the case with ammonium compounds, antimony, ipecac 

 and senega. They may be divided into those that increase and 

 liquefy the secretions,' as in dry cough, and those which diminish 

 secretions. They may also be divided as follows : 



1. Increasing Secretions. 



A. Depressant 



Nauseant or Ipecacuanha 



Sedative Apomorphine 



Tartar Emetic 



Senega 



Lobelia 



B. Indifferent Neutral salts (iodides) 



Carbonates 

 Pilocarpine 



0. Stimulant Ammonium salts (carbonate and chloride) 



Digitalis 

 Squill 



2. Decreasing Secretions. 



Atropine Aromatic products 



Acids Benzoic acid 



Turpentine Benzoates 



Terpine hydrate Balsams 

 Essential oils Tar 



(SoUmann) 



