How quickly does pepcid work? If it is close to the time for your next dose, skip the missed dose and go back to your normal time. Pin On Products Original strength pepcid ac® and maximum strength pepcid ac® contain an h2 blocker that begins to work in 15 minutes and helps control acid all day or all night. Does pepcid ac work immediately . Pepcid does help reduce facial flushing from asian glow but it comes with its own health. When it comes to taking pepcid with alcohol, there have been conflicting results as to whether it has an interaction. Can you take 2 pepcid ac a day? Pepcid is the brand name for famotidine.it works as an antihistamine to reduce the production of acid and prevent irritation.pepcid is approved to treat conditions like gerd, stomach ulcers, esophagitis, and other digestive conditions. * pepcid complete® combines an h2 blocker with an antacid that starts neutralizing acid in seconds, so it works even faster. Is that normal to take so long? Or...