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Drugs, Supplies and Delivery
Omeprazole
Omeprazole is a proton pump inhibitor (PPI) widely used to reduce gastric acid secretion. It is effective in treating conditions such as gastroesophageal reflux disease (GERD), peptic ulcers, and Zollinger-Ellison syndrome. Omeprazole is known for its potency, long duration of action, and favorable safety profile. This article synthesizes information from the British National Formulary (BNF), Lippincott Textbook of Pharmacology, and Lange Basic & Clinical Pharmacology to provide a detailed overview of omeprazole, including its mechanism, uses, dosing, side effects, precautions, and drug interactions.
Omeprazole is a prodrug that is activated in the acidic environment of the stomach. It irreversibly inhibits the H+/K+-ATPase (proton pump) on the secretory surface of gastric parietal cells. By blocking this enzyme, omeprazole:
- Reduces basal and stimulated gastric acid secretion, including acid secretion induced by food, histamine, and gastrin.
- Increases gastric pH, promoting healing of acid-related damage and providing symptomatic relief (Lippincott, Lange).
Omeprazole’s effects last up to 24 hours, making it suitable for once-daily dosing (BNF).
- Gastroesophageal Reflux Disease (GERD):
- Provides symptomatic relief and promotes healing of esophagitis (BNF).
- Peptic Ulcer Disease:
- Used for the treatment and prevention of gastric and duodenal ulcers (Lippincott).
- Zollinger-Ellison Syndrome:
- Manages excessive gastric acid secretion in this rare condition (Lange).
- Helicobacter pylori Eradication:
- Used in combination with antibiotics (e.g., clarithromycin, amoxicillin) to eradicate H. pylori and prevent ulcer recurrence (BNF).
- Stress Ulcer Prophylaxis:
- Used in critically ill patients to prevent stress-related mucosal damage (Lippincott).
- Gastroesophageal Reflux Disease (GERD):
- Provides symptomatic relief and promotes healing of esophagitis (BNF).
- Peptic Ulcer Disease:
- Used for the treatment and prevention of gastric and duodenal ulcers (Lippincott).
- Zollinger-Ellison Syndrome:
- Manages excessive gastric acid secretion in this rare condition (Lange).
- Helicobacter pylori Eradication:
- Used in combination with antibiotics (e.g., clarithromycin, amoxicillin) to eradicate H. pylori and prevent ulcer recurrence (BNF).
- Stress Ulcer Prophylaxis:
- Used in critically ill patients to prevent stress-related mucosal damage (Lippincott).
- Common: Headache, nausea, diarrhea, and abdominal pain (Lippincott).
- Serious:
- Hypomagnesemia: Prolonged use may lead to low magnesium levels.
- Increased Risk of Infections: Higher risk of Clostridioides difficile and pneumonia.
- Bone Fractures: Long-term use may increase the risk of osteoporosis-related fractures (BNF).
- Hypomagnesemia: Monitor magnesium levels in patients on long-term therapy (Lippincott).
- Vitamin B12 Deficiency: Prolonged use may reduce vitamin B12 absorption; monitor levels in at-risk patients (Lange).
- Pregnancy: Use only if benefits outweigh risks; limited data available (BNF).
- Liver Impairment: Dose reduction may be necessary in patients with severe hepatic impairment (Lippincott).
- Clopidogrel: Omeprazole may reduce the antiplatelet effects of clopidogrel by inhibiting CYP2C19 (BNF).
- Warfarin: Increased risk of bleeding due to altered metabolism (Lippincott).
- Diazepam and Phenytoin: Omeprazole may increase levels of these drugs by inhibiting CYP2C19 (Lange).
- Methotrexate: Omeprazole may increase methotrexate levels, raising the risk of toxicity (BNF).
Omeprazole is the generic name for this medication. It is marketed under the brand name Losec® and Prilosec® in some regions. Generic versions are widely available and cost-effective.
