PPIs are taken before breakfast Proton Pump Inhibitors Most potent antisecretory agents, substituted benzimidazoles also known as the Proton Pump inhibitors Covalently bind to the catalytic subunit of the proton pump and negate all types of acid secretion PPIs also provide more complete inhibition of acid secretion than the H2-receptor antagonists Inhibition of acid secretion is also prolonged because of the irreversible inhibition of the enzyme caused by the covalent bond to the proton pump PPIs are more effective during the day, generally prescribed before breakfast PPIs require an acidic environment within the gastric lumen in order to become activated and bind to the proton pump at the secretary canaliculus Utilization of antacids or H2-receptor antagonists in combination with PPIs could have deleterious effects by promoting an alkaline environment and thereby preventing activation of the PPI Consequently, antacids and H2-receptors antagonists should not be used in combination with PPIs. Ref: Sabiston 20th edition PGno: 1201