PPIs include brand names such as Nexium and Prilosec. The medications, available both over the counter and by prescription, are most effective when taken on an empty stomach. PPIs circulate in the blood to block the stomach's acid pumps, which are activated when you eat.

Why are PPI taken before meals?

PPIs are most effective when the parietal cells are stimulated to secrete acid, as they are after a meal; as such, PPIs should be administered before a meal [9] . Acid inhibition by PPIs decreases gastric acid levels without the disruption of G-cells. ...

What happens if you take PPI after eating?

Taking them in this manner is usually ineffective. This is because if you take a PPI at the start of a meal or after eating, by the time it starts working, your stomach has already released most of its acid.