Esomeprazole
Esomeprazole is the S-enantiomer of omeprazole, a proton pump inhibitor used in adults and children for gastro-oesophageal reflux disease, peptic ulcer disease, NSAID-induced ulcer prophylaxis and Helicobacter pylori eradication.
- Chemical formula
- C17H19N3O3S
- CAS number
- 119141-88-7
- ATC code
- A02BC05
- Molecular weight
- 345.42 g/mol
- Drug class
- Proton pump inhibitor
- Also known as
- S-omeprazole, Esomeprazol
What is it?
Esomeprazole is the pure S-enantiomer of omeprazole, approved in 2001 for clinical use. It is supplied as oral capsules, tablets, oral suspension and parenteral solution. Esomeprazole is dispensed both with and without prescription depending on dose and country, and is part of the World Health Organization List of Essential Medicines. It is widely used for acid-related disorders and is one of the most prescribed proton pump inhibitors globally.
Mechanism of action
Esomeprazole is a substituted benzimidazole prodrug that is activated in the acidic environment of the gastric parietal cell, where it irreversibly inhibits the H+/K+-ATPase enzyme — the proton pump responsible for the final step in gastric acid secretion. Because new pumps are continuously synthesised, acid secretion gradually returns after discontinuation. The S-enantiomer has more consistent metabolism than racemic omeprazole, with higher bioavailability after multiple doses.
Pharmacokinetics
Esomeprazole is absorbed orally as enteric-coated formulations to protect against gastric acid degradation, with peak plasma concentrations reached after one to two hours. Bioavailability is approximately 64% after a single dose and increases to 89% with repeated dosing. Plasma protein binding is approximately 97%. The drug is metabolised by CYP2C19 (predominantly) and CYP3A4 to inactive metabolites. The terminal half-life is approximately one hour, but the antisecretory effect lasts much longer.
Indications
Esomeprazole is approved in adults and children for the treatment of gastro-oesophageal reflux disease, including erosive oesophagitis healing and maintenance of healing, peptic ulcer disease, prevention of NSAID-induced ulcers, Zollinger-Ellison syndrome and as part of triple-therapy regimens for Helicobacter pylori eradication. According to clinical guidelines, the lowest effective dose for the shortest necessary duration should be used, with periodic reassessment of long-term therapy.
Safety profile
Common adverse effects include headache, gastrointestinal symptoms and dizziness. Long-term use has been associated with potential reductions in vitamin B12 and magnesium absorption, an increased risk of bone fractures, kidney injury and possible enteric infections including Clostridioides difficile. According to the prescribing information, long-term proton pump inhibitor therapy should be regularly reassessed, with monitoring of magnesium and bone health where indicated. Drug interactions through CYP2C19, including with clopidogrel, should be reviewed.
Products containing this ingredient
Frequently asked questions
How is esomeprazole different from omeprazole? ▾
Esomeprazole is the pure S-enantiomer of racemic omeprazole, while omeprazole contains both R and S enantiomers. The S form has more consistent metabolism with higher bioavailability after multiple doses, particularly in CYP2C19 extensive metabolisers. Clinical efficacy is broadly comparable at equivalent doses, although esomeprazole may produce slightly faster healing in erosive oesophagitis. Choice between the two is made by the prescriber.
Can esomeprazole be taken long-term? ▾
Esomeprazole is commonly used for prolonged periods in chronic GORD, Barrett's oesophagus and peptic ulcer prophylaxis with NSAIDs. Long-term use has been associated with potential reductions in vitamin B12 and magnesium absorption, an increased risk of bone fractures and possible enteric infections. According to international guidelines, long-term proton pump inhibitor therapy should be regularly reassessed, with the lowest effective dose used.
Does esomeprazole interact with clopidogrel? ▾
Esomeprazole is a CYP2C19 inhibitor, and CYP2C19 is responsible for activating the antiplatelet prodrug clopidogrel. Pharmacokinetic studies have shown reduced active metabolite concentrations and antiplatelet effect when these two drugs are co-administered. According to the prescribing information and several regulatory communications, the combination should be avoided when possible; alternative proton pump inhibitors such as pantoprazole are preferred in patients on clopidogrel.
When should esomeprazole be taken? ▾
Esomeprazole is most effective when taken approximately 30 to 60 minutes before a meal, ideally before breakfast, because the proton pumps are most active during meals. According to the prescribing information, capsules should be swallowed whole with water, although they can be opened and the granules sprinkled on soft food in patients with swallowing difficulties. The granules must not be crushed or chewed.
What are the main contraindications for esomeprazole? ▾
Esomeprazole is contraindicated in known hypersensitivity to esomeprazole, omeprazole or substituted benzimidazoles, and in concurrent use with rilpivirine. Caution is required in severe hepatic impairment, in long-term use with monitoring of magnesium and bone density, and during pregnancy and breastfeeding. According to the prescribing information, the medical history must be reviewed by a clinician before any prescription.
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