CIRCUMSTANCES MODIFYING THE ACTION 

 OF DRUGS. 



Mode of Administration. 



The following table gives the various methods of admin- 

 istering drugs in order of their rapidity of absorption, 

 beginning with the method by which absorption is most 

 rapid, and following with those by which absorption is less 

 and finally least rapid. 



1. By injection into the veins. 



2. By inhalation. (Volatile drugs.) 



3. By injection into subcjutaneous tissues. 



4. By injection into the trachea. 



5. By the mouth. 



6. By the rectum. 



7. By the skin. 



1. Injection into the veins, or intravenous injection 

 (usually into the jugular vein), is now rarely practised, since 

 a violent action is induced by the sudden entrance of a drug 

 into the circulation, and phlebitis, embolism and thrombosis 

 may result. The intravenous use of hot normal salt solution 

 is frequently valuable in haemorrhage, shock, and poisoning 

 (see p. 701). 



2. Volatile drugs are absorbed with great rapidity and 

 effect owing to the enormous vascular surface of the lungs 

 in contact with the inhaled vapor. Ether, chloroform, 

 ammonia and amyl-nitrite are given by this method. Inhala- 

 tion of medicated steam and sprays, used mainly for their 

 local action on the respiratory tract, are also absorbed to 

 some extent by the bronchial mucous membrane and lungs. 



3. Subcutaneous or hypodermatic injection is suitable 



