Dexilant (dexlansoprazole) is a Proton Pump Inhibitor which works by stopping some of the acid producing cells that line the stomach wall from working. It is not an instant remedy like an antacid and requires a few days' build up in the system to become effective.   If you are finding your acid is under control in the morning when you take your drugs but not in the evening, have you experimented by taking half your medication in the morning and half in the evening? In theory it shouldn't make a difference but it's what many patients do when they are on large doses of PPI.   Dexilant is the newest PPI but newest doesn't always equate to best. Although all research evidence has shown all PPIs to be as effective as each other, for some reason some people seem to get on better with one rather than another. Pantoprazole (protonix) is better tolerated by some.   Of course, you can treat acid reflux with an antacid (such as Tums) or an alginate (such as Gaviscon) for instant relief but don't take them within a couple of hours of your PPI.   But you can also try to determine what's causing your reflux. Keep a food diary to see if you can determine trigger foods. And I assume you are following lifestyle advice? - Lose weight, wear loose clothing, don't do any exercise that will compress the stomach after eating.   Years ago, when I was first put on PPIs, I used to have horrednous heartburn, like a blow torch down my throat, that would flare up at different times. This was esophagitis which took weeks to calm down.