Introduction-Anaphylactic
reaction
· IgE
-mediated type I hypersensitivity reaction.
· Effects
are due to wide spread degranulation of mast cells.
· A
dose independent unpredictable adverse drug reaction
Mechanism:
Commonly associated with a previous exposure to a
similar group of drugs or chemicals. Foreign proteins act as antigens and
stimulate production of IgEantibodies. They bind to mast cells and
basophils, and with subsequent exposure massive degranulation occurs due to
these already formed antibodies reacting with new antigens.
There is a massive release of mediators : Eg –
Histamine, leukotrienes, tryptase, protease.
They give rise to bronchoconstriction,
vasodilatation and increased capillary permeability.
