MadSci Network: Medicine |
You see anaphylaxis is an advanced form of allergic reaction, when the histamine has already been released from the mast cells and other inflammatory cells. Administering an antihistamine, depending on its mechanism of action, can not necessarily displace the histamine that has already bound with the histaminic receptors and the effects that take place subsequently down stream. Anaphylaxis causes a circulatory collapse and to prevent catastrophic loss of blood pressure and vascular tone you need to administer epinephrine to counter act the loss of blood pressure. While antihistamines are part of the treatment for anaphylaxis they are not the only treatment and cannot compeletely overcome the deleterious effects of anaphylaxis. Hope this helps, If you have some further questions please feel free to ask. thanks
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