DIGITALIS 



75 



5. A local irritant action. 



External and Local Action. There is no action upon the 

 unbroken skm, but it is an irritant to the mucous membranes and 

 subcutaneous tissues. When administered subcutaneouslv, it causes 

 pam at the site of injection and through its irritant action may cause 

 destruction of tissue with the formation of a slough or sterile abscess. 



^%f%%ft^^ 



Fig. 6.— Normal blood-pressure tracing. The upstroke represents the heart sys- 

 tole, dowDstroke the commencement of diastole. 



(Reproduced, by permission, from Pittenger's Biochemic Drug Assay Methods. Published 

 by P. Blaliiston's Sons and Co.) 



Fig. 7. — Action of digitalis, therapeutic stage. Note the increased length of up- 

 stroke (increased strength of contraction) ; also the increased space between 

 the upstrokes (prolonged diastole). 



(Reproduced, by permission, from Pittenger's Biochemic Drug Assay Methods. Published 

 by P. Blakiston's Sons and Co.) 



Consequently, hypodermic medication is to be avoided. Digitoxin is 

 the most irritating and digitalein the least irritating of the glucosides. 

 Digestive System. Digitalis is a slight gastro-intestinal irri- 

 tant, sometimes producing gastritis and diarrhea. On this account 

 the drug is not well tolerated by certain animals. Emesis may 



