Antacids can cause side effects such as constipation and diarrhea. Histamine-2 (H2) blockers, also called H2-receptor antagonists, are another OTC acid reflux medication. They work by binding to ...

1942—Antergan becomes the first antihistamine tested in humans and goes on the market. 1972—James Black discovers the H2 receptor and characterizes its antagonist, burimamide. 1999 ...