Esomeprazole is a proton pump inhibitor (PPI) that provides potent, prolonged suppression of gastric acid. It is the S-isomer of omeprazole and was developed to deliver more consistent bioavailability and slightly greater acid suppression than the racemate. PPIs act within the secretory canaliculus of the gastric parietal cell, where they are protonated and form a covalent (irreversible) bond with the luminal H+/K+-ATPase. By inactivating this final step of acid secretion, esomeprazole reduces both basal and stimulated acid output regardless of the upstream trigger (histamine, gastrin, or acetylcholine).
After oral dosing, enteric-coated granules protect the drug from degradation in the stomach and release it in the small intestine. Peak plasma concentrations occur within 1–2 hours. Because the pump is resynthesised over time, once-daily dosing maintains acid suppression across 24 hours; twice-daily dosing may be used in refractory cases or for Helicobacter pylori eradication regimens. Compared with some PPIs, esomeprazole shows lower inter-individual variability and a higher proportion of time with intragastric pH above 4, which correlates with mucosal healing in erosive disease.
Clinically, esomeprazole is used for gastro-oesophageal reflux disease (GERD/GORD), peptic ulcer disease, prophylaxis of NSAID-associated ulcers, eradication of H. pylori (as part of combination therapy), and hypersecretory conditions such as Zollinger–Ellison syndrome. It improves heartburn and regurgitation, heals erosive oesophagitis, and prevents relapse when maintenance therapy is indicated. In hospital settings, IV esomeprazole can be used where oral administration is not possible or when rapid suppression is desired.
Symptom relief often starts within days, but complete mucosal healing typically requires 4–8 weeks. Long-term therapy should be reviewed periodically to ensure the lowest effective dose is used, balancing symptom control with recognised risks of chronic acid suppression. Lifestyle measures—weight management, head-of-bed elevation, avoidance of late meals, smoking cessation, and trigger-food reduction—enhance outcomes.
Review the ongoing indication regularly. Consider step-down to the minimum effective dose once control is achieved.
Esomeprazole is generally well tolerated. Most adverse effects are mild and self-limiting; serious reactions are uncommon but recognised, particularly with prolonged high-dose use.
Rebound acid hypersecretion can occur after abrupt discontinuation following long-term therapy; step-down or on-demand approaches may ease transition.
Educate patients on lifestyle strategies that complement PPIs (weight reduction, head-of-bed elevation, avoiding late heavy meals, limiting alcohol, and smoking cessation).
Key mechanisms are increased gastric pH altering drug absorption and CYP2C19-mediated interactions. Provide clinicians/pharmacists with a complete list of medicines and supplements.
Taking esomeprazole before meals improves binding to active proton pumps and enhances efficacy.
Missed dose: take as soon as remembered if not close to the next scheduled dose. If nearly time for the next dose, skip the missed dose. Do not take two doses together.
Accidental double dose: usually results in mild symptoms (headache, nausea, abdominal discomfort). Avoid further extra doses and contact a clinician or pharmacist if unwell.
Large overdose: serious toxicity is rare but may cause confusion, drowsiness, blurred vision, tachycardia, nausea/vomiting. Seek medical attention. Hospital management is supportive; activated charcoal may be considered within a short window post-ingestion.
Always follow the label and the prescriber’s instructions. Seek urgent care for black stools, vomiting blood, severe abdominal pain, or persistent diarrhoea.
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