50 GENERAL, ACTIONS OF DRUGS 



copious foul secretion is treated with volatile oils, which 

 exert an antiseptic action on the air passages. Expectorants 

 are usually administered with other agents influencing the 

 respiratory tract ; e.g., drugs relieving cough and spasm and 

 those stimulating the respiratory movements or circulation. 



Drugs Stimulating the Eespiratoet Centres. 



Strychnine Stramonium 



Atropine Ammonium carbonate 



Belladonna btrong ammonia 



Hyoscyamus 



External counter-irritation and heat. 



Drugs Depressing the Kespiratoky Centres. 



Many drugs depress and paralyze the respiratory centres 

 in large doses, but they are seldom used medicinally for 

 this purpose. 



Uses. — Drugs stimulating the respiratory centres and 

 movements are of great value in diseases of the chest — 

 especially bronchitis— attended with obstruction in the air 

 passages and cyanosis. They promote coughing and efforts 

 at expulsion of secretion aud facilitate the entrance of 

 oxygen into the blood. Some, possibly ammonia, stimulate 

 the movements of the cilise lining the tiacheal mucous 

 membrane. 



Strychnine is, perhaps, the most powerful respiratory 

 stimulant ; atropine is indicated where exudation is abundant, 

 while ammonium carbonate is prescribed to increase secre- 

 tion. Certain drugs sometimes cause in large doses Cheyne- 

 Stokes breathing in animals, e.g., opium, chloral, bromides, 

 digitalis, ammonium carbonate and strychnine, owing to 

 disturbance of the respiratory centre. 



Drugs Relaxing Spasm of the Bronchial Muscular 

 Tunic and Eelieving Cough. 



LOCALLY 



White of egg Linseed tea 



Mucilage Syrups 



External counter-irritation and heat 



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