Last reviewed 2026-04-22 · How we verify

Nexium®

Nexium inhibits gastric acid secretion by blocking proton pumps in the stomach lining.

Nexium inhibits gastric acid secretion by blocking proton pumps in the stomach lining. Used for Gastroesophageal reflux disease (GERD), Peptic ulcer disease, Zollinger-Ellison syndrome.

At a glance

Mechanism of action

Esomeprazole, the active ingredient in Nexium, is a proton pump inhibitor (PPI) that irreversibly binds to and inactivates the H+/K+-ATPase enzyme in gastric parietal cells. This blocks the final step of gastric acid production, significantly reducing stomach acid levels. It is used to treat conditions caused by excess gastric acid and to promote healing of acid-damaged tissues.

Approved indications

• Gastroesophageal reflux disease (GERD)
• Peptic ulcer disease
• Zollinger-Ellison syndrome
• Prevention of NSAID-induced ulcers

Common side effects

• Headache
• Diarrhea
• Nausea
• Abdominal pain
• Constipation

Key clinical trials

• Endoscopic Evidence of Maintenance of Healing With Oral NEXIUM in Patients 1 to 11 Years Old With Erosive Esophagitis. (PHASE3)
• The Bioavailability and Effect on Pouch pH of Esomeprazole After Gastric Bypass (PHASE4)
• Study Comparing Esomeprazole Associated With Sodium Bicarbonate From Eurofarma and Esomeprazole in Treatment of Gastroesophageal Reflux Disease ESOBIC (PHASE3)
• A Phase III Clinical Trial for Efficacy and Safety Evaluation of JP-1366 Tablets on Reflux Esophagitis (PHASE3)
• PROGRESSive Withdrawal Esomeprazole and Acid-related Symptoms (PHASE4)
• The Efficacy of the 7 Days Tailored Therapy as the 1st Eradication of H. Pylori Infection (NA)
• A Study in Healthy Men to Test How Esomeprazole Influences the Amount of BI 1819479 in the Blood (PHASE1)
• The Selection Criteria for the Second-look Endoscopy Among Patients With Bleeding Peptic Ulcers

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.