Omeprazole, sold under the brand names Prilosec and Losec among others, is a medication used in the treatment of gastroesophageal reflux disease (GERD), peptic ulcer disease, and Zollinger–Ellison syndrome. It is also used to prevent upper gastrointestinal bleeding and is commonly administered as an enteric coated oral formulation to protect the acid-labile prodrug until it reaches the intestinal absorption site. Chemically it is a substituted benzimidazole (C17H19N3O3S, molecular weight about 345.4 g/mol) and is formulated as a racemate; the S-enantiomer is marketed separately as esomeprazole. Omeprazole is a proton pump inhibitor that irreversibly inhibits the gastric H+/K+ ATPase on parietal cells after acid-mediated activation, producing a sustained reduction in gastric acid secretion beyond its plasma half life. It is extensively metabolized in the liver primarily via CYP2C19 and CYP3A4, which contributes to interindividual variability in exposure and to clinically relevant drug interactions. Typical pharmaceutical descriptions note onset of anti-secretory effect within 1 to 4 hours after dosing with maximal acid suppression achieved after several days of repeated dosing; formulations and stability depend on protection from acid and oxidation.
Parent: Omeprazole
Parent: Omeprazole
Parent: Omeprazole
Parent: Omeprazole / Esomeprazole
Parent: Omeprazole / Esomeprazole
Parent: Omeprazole / Escitalopram
Parent: Omeprazole
Parent: Omeprazole
Parent: Omeprazole
Parent: Omeprazole Magnesium / Omeprazole
Parent: Omeprazole
Parent: Omeprazole
Parent: Omeprazole
Parent: Omeprazole
Omeprazole and its pharmaceutical preparations are monitored for a defined set of related substances and degradation products that arise from oxidation, dealkylation, and ring transformations, the most common being omeprazole sulfone, omeprazole sulfoxide, 5-hydroxyomeprazole, and O-desmethyl or N-desmethyl derivatives. Industry and pharmacopeial monographs typically apply reporting thresholds in the 0.05 to 0.10 percent range by weight for individual impurities and often specify acceptance limits for individual known impurities in the approximate range of 0.1 to 0.5 percent, with total related substances commonly limited to about 1.0 to 2.0 percent depending on the product and regulatory jurisdiction. Oxidative degradants such as the sulfone and sulfoxide are specifically controlled at tighter levels because they form under stressed storage conditions, and stability indicating assays routinely use reversed phase HPLC with UV detection and LC-MS for identification and quantitation.
Omeprazole is used to reduce gastric acid secretion in conditions such as GERD, peptic ulcer disease, and Zollinger Ellison syndrome, and to prevent upper gastrointestinal bleeding in at-risk patients; it is prescribed for healing acid related lesions and for maintenance therapy where indicated.
The most notable risks with longer term use are nutrient and infection related: reduced absorption of magnesium, calcium, and vitamin B12 can occur, and there is a modestly increased risk of enteric infections such as Clostridioides difficile; acute adverse effects can include headache, nausea, and abdominal pain.
Daily dosing is common and appropriate for many chronic acid related conditions but long term use should be reviewed with a clinician to assess ongoing need, monitor for adverse effects, and consider lowest effective dose or step down strategies when possible.
Prilosec is a brand name for omeprazole; the active chemical entity omeprazole is the same whether supplied as a brand product or as a generic, though formulations and excipients may differ among manufacturers.
