Single 20 to 40mg oral doses generally give rise to peak plasma esomeprazole concentrations of 0.5-1.0mg/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 1–3mg/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.