ACETANILID AND ANTIPYRINE 117 



The skin vessels are dilated in fever probably through action on 

 the heat regulating center. 



Nervous System. Acetanilid is a powerful analgesic, and a 

 slight sedative to the nerves and cord. Small doses are slightly 

 stimulant to the brain, larger ones may be sedative and tend to 

 produce drowsiness. Large or toxic doses may excite convulsions 

 which appear to be of spinal origin in some cases, of cerebral origin 

 in others. 



Temperature. In health singlfe or moderate doses do not have 

 any influence upon temperature, but in fever acetanilid is a very 

 strong antipyretic. Its antipyretic action is due almost entirely 

 to action npon the heat regulating center. It does not in any 

 way reduce heat production because it does not reduce metabolism. 

 It is believed that it aids the heat regulating center to improve 

 its control over the mechanisms of heat dissipation, which are the 

 ones at fault in infectious fevers. This central action is shown 

 by the fact that it does not lower normal temperature, if the cord 

 is divided, and by the fact that there is no effort made by the 

 organism to produce more heat, shivering, etc., as when the tem- 

 perature is lowered by cold applications. The reduction of tempera- 

 ture may be accompanied by sweating but this is of central origin 

 and temperature will still be lowered if the sweating is prevented 

 by atropine. Its effects are usually produced promptly and last for 

 several hours. 



Absorption, Elimination and Metabolism. It is absorbed 

 rapidly and soon escreted as oxidized products. It is a feeble diu- 

 retic, increases urea and uric acid, and renders the urine darker in 

 color. 



Therapeutics. 



1. In fevers to reduce the temperature when dangerously high 

 and to promote the comfort of the animal by lessening pain, 



2. Analgesic. It is especially valuable for the relief of the " so- 

 called " functional pains in man, neuralgias, etc., but is less im- 

 portant to veterinarians for this purpose although Quitman gives 

 acetanilid analgesic properties in horses. 



3. Laminitis. It has been reported as very successful in the 

 German army for the treatment of this disease. In this case large 

 doses (3iv — viij) are given three or four times daily. 



4. Externally, As a dusting powder for wounds, gaUs, etc., 

 either alone or in combination with boric acid, talcum, etc. 



ANTIPYRINA. ANTIPYRINE 



Synonym. Analgesin 



This is also a coal tar product. It is obtained by the action of 

 phenyl hydrazine upon diacetic ether and then methylating the re- 



