PPI with CYPP450 enzyme inhibiting activity (LQ)
a. Omeprazole has maximum enzyme inhibiting action on CYPP450 among PPI. The drug can inhibit metabolism of warfarin and therefore can lead to bleeding. Pantoprazole is claimed to have lesser possibility of drug interactions and stable pharmacokinetics.
b. Rabeprazole has best 24 hours pain relief and the drug has marginally better efficacy than other proton pump inhibitors. Esomeprazole is an optical isomer of omeprazole (BG Katzung’ 10th Edition, 2010).
c. Proton pump inhibitors have revolutionized the management of acid-peptic disorders in recent years. They have a broadly similar mechanism of action and are extensively metabolized in the liver via cytochrome P450 2C19 and 3A4 enzymes. A wide inter-individual variability in pharmacokinetics due to polymorphism in cytochrome P450 2C19 has been demonstrated for the first-generation proton pump inhibitors.
d. As a therapeutic group, the PPIs are highly useful for the relief of symptoms and healing of gastro esophageal reflux disease, gastric and duodenal ulcer disease, eradication of Helicobacter pylori infection, prevention and treatment of NSAID associated damage, management of hypersecretory states such as Zollinger-Ellison syndrome, and care of patients with non-variceal upper gastrointestinal bleeding, or non-ulcer dyspepsia.
e. Since their release, various studies have confirmed that PPIs are superior to H 2 -receptor antagonists as acid inhibitory agents. Their ability to control 24-hour intragastric pH and, in particular, maintain a pH above 4 is important for healing of acid peptic lesions in the oesophagus.
(Remember: Omeprazole has maximum enzyme inhibiting action on CYPP450 among PPI)