Structural Biochemistry/Nexium

Description
Esomeprazole, brand name known as Nexium, is categorized as a group of drugs called proton pump inhibitors. By inhibiting ATPase in gastric parietal cells, Esomeprazole decreases the amount of acid secretion in the stomach. This drug is mainly used for people with gastroesophageal reflux disease (GERD), a disease in which an excessive amount of gastric acid causes a backflow from the stomach and thus leading to the burning of the esophagus. By preventing the formation of gastric acid, Esomeprazole allows the injured esophagus to heal and prevent further damages.

Drug Structure
The molecular formula of Esomeprazole is (C17H18N3O3S)2Mg* 3 H2O, The structural formula is shown below.

Pharmacokinetics
Single 20–40 mg oral doses generally give rise to peak plasma esomeprazole concentrations of 0.5-1.0 mg/L within 1–4 hours, but after several days of once-daily administration these levels may increase by about 50%. A 30 minute intravenous infusion of a similar dose usually produces peak plasma levels on the order of 1–3 mg/L. The drug is rapidly cleared from the body, largely by urinary excretion of pharmacologically-inactive metabolites such as 5-hydroxymethylesomeprazole and 5-carboxyesomeprazole. Esomeprazole and its metabolites are analytically indistinguishable from omeprazole and the corresponding omeprazole metabolites unless chiral techniques are employed.

Side effects
Studies have showed patients who receive high-dose of Esomprazole have increased risk of fractures of the hip, wrist, or spine. High dose defines as multiple intakes every day for a long term period. In addition, Esomeprazole may cause serious side effects such as the following:

•blisters

•hives

•rash

•itching

•difficulty breathing or swallowing

•irregular, fast, or pounding heartbeat

•uncontrollable shaking of a part of the body

•seizures

•stomach pain

•fever