Esomeprazole

Esomeprazole, sold under the brand name Nexium [or Neksium] among others,^[2] is a medication which reduces stomach acid.^[11] It is used to treat gastroesophageal reflux disease, peptic ulcer disease, and Zollinger–Ellison syndrome.^[11][12] Its effectiveness is similar to that of other proton pump inhibitors (PPIs).^[13] It is taken by mouth or injection into a vein.^[11]

Common side effects include headache, constipation, dry mouth, and abdominal pain.^[11] Serious side effects may include angioedema, Clostridioides difficile infection, and pneumonia.^[11] Use in pregnancy appears to be safe, while safety during breastfeeding is unclear.^[3] Esomeprazole is the (S)-(−)-enantiomer (or less specifically the S-isomer) of omeprazole.^[11] It works by blocking H⁺/K⁺-ATPase in the parietal cells of the stomach.^[11]

It was patented in 1993 and approved for medical use in 2000.^[14] It is available as a generic medication and sold over the counter in several countries.^[15][12] In 2022, it was the 122nd most commonly prescribed medication in the United States, with more than 5 million prescriptions.^[16][17] In Australia, it was one of the top ten most-prescribed medications between 2017 and 2023.^[18] It is also available in lower dose formulations without a prescription in the United States,^[19] the United Kingdom^[20] as well as Australia, Canada, and New Zealand.^[21]