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• Gastroesophageal Reflux Disease (GERD): Treatment of erosive and non-erosive reflux esophagitis; maintenance of healing.
• Peptic Ulcer Disease: Treatment of active duodenal and benign gastric ulcers.
• Helicobacter pylori Eradication: Used in combination with antibiotics for H. pylori infection.
• Zollinger-Ellison Syndrome: Management of pathological hypersecretory conditions.
• NSAID-associated Ulcers: Prevention and treatment in patients requiring chronic NSAID therapy.
• Off-label: Functional dyspepsia, stress ulcer prophylaxis in critically ill patients, laryngopharyngeal reflux, Barrett’s esophagus symptom management.

• Route: Oral (capsules, tablets, suspension), IV (in select formulations).
• Adults:
• GERD: 20 mg once daily for 4–8 weeks; maintenance 20 mg daily.
• Duodenal ulcers: 20 mg daily for 4 weeks; may extend to 8 weeks.
• Gastric ulcers: 40 mg daily for 4–8 weeks.
• H. pylori eradication: 20 mg twice daily plus antibiotics for 10–14 days.
• Zollinger-Ellison: Initial 60 mg daily; titrate as needed up to 120 mg/day.
• Pediatrics:
• 1 month to 16 years: Dose based on weight (e.g., 0.7–1 mg/kg/day).
• Elderly: No dose adjustment needed.
• Renal impairment: No dose adjustment needed.
• Hepatic impairment: Reduce dose to 10–20 mg daily in severe liver disease.

Omeprazole is a proton pump inhibitor that irreversibly blocks the H⁺/K⁺-ATPase enzyme system of gastric parietal cells, suppressing gastric acid secretion regardless of the stimulus. This reduction in acid allows healing of ulcers and relief of reflux symptoms.

• Absorption: Well absorbed; bioavailability ~30–40% initially, increasing with repeated dosing.
• Peak plasma concentration: 0.5–3.5 hours.
• Half-life: ~0.5–1 hour (effect lasts longer due to irreversible binding).
• Metabolism: Extensive hepatic metabolism via CYP2C19 and CYP3A4.
• Excretion: Primarily renal (80%) and fecal.

• Pregnancy: Low risk based on available data; no known teratogenic effects. Use when benefits justify risks.
• Lactation: Excreted in small amounts in breast milk; generally considered safe.

• Proton Pump Inhibitor (PPI), benzimidazole derivative.

• Hypersensitivity to omeprazole or other PPIs.
• Concurrent use with rilpivirine.
• Known severe hepatic impairment without dose adjustment.

• Risk of Clostridioides difficile infection with prolonged use.
• Possible increased risk of bone fractures with long-term use.
• Monitor magnesium levels during extended therapy.
• Potential for vitamin B12 deficiency with prolonged treatment.
• Rebound acid hypersecretion may occur after stopping therapy.

• Common: Headache, abdominal pain, nausea, diarrhea, constipation, flatulence.
• Rare: Hypomagnesemia, liver enzyme elevation, rash, dizziness.
• Serious: Interstitial nephritis, bone fractures, C. difficile-associated diarrhea.

• Reduces activation of clopidogrel (avoid coadministration).
• May increase levels of warfarin, diazepam, phenytoin.
• Decreases absorption of drugs requiring acidic environment (e.g., ketoconazole).
• Metabolized via CYP2C19 and CYP3A4; inhibitors or inducers of these enzymes affect levels.

• FDA alerts highlight risks of long-term use including hypomagnesemia and fractures.
• Guidelines recommend lowest effective dose and duration.
• Remains on WHO Essential Medicines List.

• Store at 20°C to 25°C (68°F to 77°F), protected from moisture and light.
• Do not freeze.
• For suspensions, refrigerate after reconstitution and use within prescribed time.