Why does Pepcid AC stop you from turning red when you drink?

I—like many people—am missing the enzyme to break down alcohol in your system. This means that I get drunk very easily, and also turn very red when I am drinking. A friend who has the same problem recently told me that if you take a Pepcid AC (which is a heartburn medication), you won’t flush when you drink. I tried it—it totally works. But why? It seems like turning red has nothing to do with acid reflux.