well starting with problem of anaphylctic shock it can be due to some anaesthetics used prior to dental procedures such as lignocaine the best way to counter this is giving an i.m. injection of adrenaline 0.5ml of 1:1000 solutionis life saving.

also adrenaline is used fr control of haemmorage ,proper functioning of LA,s used in acute bronchial asthma
so east or best adrenaline is best and about your 500mg query idont find any drug but if used in incrememnts for 3 days hemisuccinate or antihistamine can be usED
PRAKHAR THAKUR BDS 2nd year INDIA
Email address;
pthakur842@gmail.com-weighting for your reccomendations