328 HEMOSTATICS OR STYPTICS 



dation for their use with the exception of the fact that they do arrest 

 hemorrhage when applied locally. The tannic acid preparations un- 

 dergo changes before they are absorbed which render them useless 

 for hemorrhages beyond the digestive tract. On the other hand, 

 there is little reason to believe that the mineral astringents circulate 

 in the blood in sufficient concentration to be in any way effective. 



2. Agents to Lower Blood Pressure. This is not a very im- 

 portant group therapeutically but they should not be overlooked. 

 They might be used unless the hemorrhage has been profuse. One 

 of the first considerations of the treatment of internal hemorrhage 

 is to put the patient at rest and keep it as quiet as possible, since 

 rest favors the formation of a clot, while motion favors bleeding or 

 breaking dovro. of the clot. Some of the hypnotics are particularly 

 serviceable for this purpose. Morphine is exceptionally useful in 

 dog and man. The bleeding part should be raised as much as possi- 

 ble as this tends to lower blood pressure in the part. 



Vasodilators do not give very satisfactory results. As hemostat- 

 ics they should dilate all the vessels except the bleeding ones but of 

 course this action is impossible to obtain. They would be indicated, 

 if at all, in hemorrhages from vessels not easily dilated as in the 

 muscles and lungs. 



3. Vasoconstrictors. These are in a class similar to the dila- 

 tors. That is, for therapeutic action to control hemorrhage, they 

 should constrict the bleeding vessels but dilate the others. The great 

 obstacle in the path of the constrictors in arresting hemorrhages is 

 that a general vasoconstriction is accompanied with a rise of blood 

 pressure. Consequently although these agents may constrict the 

 bleeding vessels, in so doing they raise arterial tension to such an 

 extent as to equal if not more than compensate for any effect the 

 constriction would have upon the bleeding part. 



There are a few exceptions to the last statement, however, as 

 there is no doubt but that ergot and hydrastinine are very efficacious 

 in post partum hemorrhage, but their value in other hemorrhages is 

 very doubtful. 



Adrenaline belongs to this group and clinical experience seems 

 to indicate that it is of considerable value in distant hemorrhage al- 

 though it does increase blood pressure. 



4. Coagulants. These drugs increase the coagulability of the 

 blood which is desired when there is severe bleeding from slight 

 wounds as in purpurea hemorrhagica, hemophilia, epistaxis, hemopta- 

 sis, renal and intestinal hemorrhage, etc. The principal drugs used 

 for this purpose are gelatin, calcium lactate and calcium chloride. 

 With the exception of gelatin, stypticin and the calcium salts, the dif- 

 ferent members of these groups have been discussed in other places. 



