H2-blockers are drugs that block the histamine receptors in the stomach to reduce acid secretion. The chemical histamine, the same substance released during an allergic reaction, stimulates certain cells in the stomach to produce acid. It does this by attaching, or binding, to a particular site on those cells - known as H,-receptors. An H^-antagonist, or blocker, works by binding to H,-receptors, and thus “blocks” the cells from producing acid.
Because H,,-blockers are used to reduce acid secretion in the stomach, they are not effective once you begin experiencing the symptoms of LPRD. To be effective, they must be taken regularly before meals. H,,- blockers cause relatively few side effects. The most common are diarrhea and other digestive disturbances, headache, dizziness, and tiredness, or hair loss with Tagamet (cimetidine) and sweating with Axid (nizatidine). One H2-blocker, Zantac (ranitidine, bismuth citrate), can cause the tongue to darken and stools to turn black. H9-blockers are often pre-
scribed in addition to PPIs. These medications come in OTC and prescription formulas. Some common H2-blockers are nizatidine (Axid), famotidine (Pepcid), cimetidine (Tagament), and ranitidine (Zantac).