336 IRRITANTS AND COUNTERIRRITANTS 



Those used for local systemic effect are : 



Chrysarobin Balsam of Peru 



Oil of cade Jequirty 



CANTHARIS 



Synonyms. Spanish Flies, Cantharides 



This is official as the dried beetles, Cantharis vesicatoria, largely 

 secured from the southern part of Europe. Its active principle is 

 cantharidin, an anhydrid of cantharidic acid. It is a crystalline body 

 forming soluble salts with alkalies. 



Preparations. 



Tindura Cantharidis 10 per cent. H. 1l\,xxx — 3j ; 2. — . 

 D. triij— tn,v; 0.13 — 1. 



Ceratum Cantharidis. Cantharides 36 gms., Glacial acetic 

 acid 2.5 mils, oil of turpentine 1.5 mils, yellow wax and 

 rosin each 17.5 gms., and benzoinated lard 20 gms. 



Collodium Cantharidatum, 60 per cent. Cantharides. 



Externally and Locally. Applied to the skin, cantharides pro- 

 duces irritation, redness and burning, followed by vesication. If 

 the action is allowed to continue, it may lead to pustulation, or ul- 

 ceration and sloughing. When applied in properly prepared oint- 

 ment, vesication will be produced in from 3 — 12 hours. The effects 

 are not believed to extend very deeply, but it is one of the most 

 useful blisters in veterinary medicine. But if the blister is too 

 strong or used too freely, inflammation of the deeper layers of the 

 skin may occur with suppuration and in extreme cases sloughing; 

 the hair bulbs become injured and a permanent blemish results. It 

 is also irritant to the mucosa. If applied to too large an area of 

 the skin, absorption may occur and result in the symptoms to be 

 described under internal action. 



Internally. There is no effect of therapeutic doses upon the 

 digestive tract except that of mild irritation. Through its elim- 

 ination by the urinary tract, small doses are slightly diuretic, genito- 

 urinary stimulant and aphrodisiac according to some authorities, 

 although any aphrodisiac power is due to its irritant action on the 

 mucosa as it escapes from the body. The action of large doses is 

 discussed under toxicology. 



Absorption and Elimination. Cantharides is absorbed from 

 all surfaces. It is sometimes absorbed from the skin in sufficient 

 amounts to give trouble and is always contraindicated in nephritis. 

 It is almost entirely eliminated by the kidneys. 



Toxicology. The symptoms of poisoning may be divided into 

 two groups: those produced upon the digestive tract before absorp- 

 tion and those produced upon the genito-urinary tract during elim- 



