i found the answer finally! it's because zantac is a histamine blocker also that primarily works in the stomach and can work elsewhere but doesn't do well on its own. "zantac is an antihistamine primarily effective for the histamine receptors in your stomach. they're called h-2 receptors. the histamine receptors in your blood vessels & nerve endings are primarily h-1 receptors with some h-2 receptors. when h-1 active anthistamines like benadryl or allegra are not sufficient to control hives zantac can be added for a little extra control. alone it's not very good. " here's a page of similar answers from doctors with more detail. <link> zantac is an antihistamine primarily effective for the histamine receptors in your stomach. they're called h-2 receptors. the histamine receptors in your blood vessels & nerve endings are primarily h-1 receptors with some h-2 receptors. when h-1 active anthistamines like benadryl or allegra are not sufficient to control hives zantac can be added for a little extra control. alone it's not very good source: healthtap <link>
my doctor told me to take both zyrtec and zantac (heartburn med. ) togther for my allergies will the combination help?