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Omeprazole 💊

⚠️ Safety notes: - There is evidence omeprazole may reduce the efficacy of clopidogrel (interaction remains under review). - Always ensure dyspepsia is not due to gastric or oesophageal cancer before starting treatment.

📖 About

Always check the BNF link here.

💊 Proton Pump Inhibitor (PPI) – highly effective acid suppression.
🔄 Multiple drug interactions due to CYP450 inhibition.
✅ Now preferred over H2 blockers for peptic ulcer disease and GORD.

⚡ Mechanism of Action

⛔ Irreversible inhibitor of the gastric parietal cell H⁺/K⁺ ATPase pump.
⬇️ Blocks final step of acid secretion into gastric lumen.
⚡ Provides profound and long-lasting gastric acid suppression.

💊 Dosing – Omeprazole (verify with BNF/datasheet)

Indication	Details
🩹 Duodenal Ulcer	Omeprazole 20 mg OD × 4 weeks (most heal in this time)
🩹 Gastric Ulcer	Omeprazole 40 mg OD × 4–8 weeks
🔥 GORD	Omeprazole 20 mg OD × 4–8 weeks
🧪 Erosive Oesophagitis	Omeprazole 10–40 mg OD
🚑 Upper GI Bleed	Omeprazole • 80 mg IV infusion in 250 mL 0.9% NaCl or 5% glucose over 60 min • Then 8 mg/hour (80 mg in 250 mL over 10 h) • Continue for 72 h (≈ 7 infusion bags, ~16 × 40 mg vials)
🧬 Zollinger–Ellison Syndrome	Omeprazole start 60–120 mg/day (individualise to response)

🔄 Interactions

🔬 Inhibits CYP2C19 → ↑ levels of diazepam, phenytoin, warfarin.
⚠️ May reduce activity of clopidogrel (requires CYP2C19 activation).
⬆️ Tacrolimus levels (monitor levels).
⬆️ Can interfere with absorption of antiretrovirals requiring gastric acidity (e.g. atazanavir).

⚠️ Cautions

🏥 Always exclude gastric/oesophageal cancer before treating “dyspepsia.”
⬇️ Reduce dose in severe liver failure to 20 mg/day.
📉 Long-term PPI use linked to: – ↑ risk of hypomagnesaemia, vitamin B12 deficiency, osteoporosis & fracture risk, and Clostridium difficile infection.

🚫 Contraindications

Hypersensitivity to omeprazole or other PPIs.
Relative caution in severe hepatic impairment (dose adjustment required).

💥 Side Effects

🤢 Common: diarrhoea, nausea, vomiting, abdominal pain, flatulence.
🧠 Headache, dizziness, insomnia.
🌡️ Skin rashes, pruritus.
🦴 Long-term: osteoporosis, fracture risk, hypomagnesaemia, B12 deficiency.
🦠 Rare: C. difficile colitis, interstitial nephritis, hepatitis.
⚡ Overall: usually well tolerated in short-term use.

📑 References

BNF: Omeprazole
NICE Dyspepsia & GORD Guidelines

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