Histamine 2 Blockers.

Zantac 75, 150, 300
Pepcid 10, 20, 40
Tagament
Axid

Histamine 2 blockers (H2 Blockers) are used for dyspepsia 
and for allergic reactions.  These products cut the
production of stomach acids.  For different people different
H2 blockers work better.  Pepcid seems to be the most
effective, however, for different people, different
products may or may not be more effective.

It takes around 1 hour to work.