Omeprazole

Omeprazole is a proton pump inhibitor that suppresses gastric acid secretion by blocking the stomach’s acid-producing enzyme. It is used for reflux, peptic ulcers, and related conditions.

Hydrogen-potassium ATPase: A membrane enzyme that exchanges hydrogen ions for potassium ions, using ATP to drive gastric acid secretion. Omeprazole’s active form binds this enzyme and inhibits its acid-secreting activity.
Gastroesophageal reflux disease: A chronic condition in which stomach contents reflux into the esophagus, causing troublesome symptoms or complications. Omeprazole reduces acid exposure and is commonly used to treat reflux symptoms and esophagitis.
H2 receptor antagonist: A drug that reduces gastric acid secretion by blocking histamine H2 receptors on parietal cells. Unlike omeprazole, it blocks an upstream signal rather than the proton pump itself.
Rebound acid hypersecretion: A temporary increase in gastric acid secretion after prolonged acid-suppressing treatment is stopped. It can produce symptoms after omeprazole withdrawal and complicate decisions about stopping treatment.
Pharmacokinetics: The study of how a drug is absorbed, distributed, metabolized, and eliminated by the body. Omeprazole’s absorption and metabolism help explain its dosing and variation between individuals.
Prodrug: A medication administered in an inactive or less active form that is converted into an active drug inside the body. Omeprazole becomes active after exposure to the acidic environment of stomach secretory canaliculi.
Peptic ulcer disease: A break in the stomach or duodenal lining that extends through the mucosal layer. Acid suppression helps ulcers heal and is often combined with treatment of their underlying cause.
Antacid: A substance that neutralizes acid already present in the stomach. Antacids act quickly on existing acid, whereas omeprazole suppresses subsequent acid secretion.
Vitamin B12 deficiency: A state in which the body lacks enough vitamin B12 for normal blood-cell production and nervous-system function. Prolonged acid suppression may reduce absorption of food-bound vitamin B12 in some people.
Bioavailability: The fraction of an administered drug dose that reaches the systemic circulation in active form. Omeprazole’s formulation and first-pass metabolism affect how much drug reaches its target.

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