Esomeprazole dosage

Recommended Adult Dosage Schedule of Oral Esomeprazole... 

AstraZeneca (formerly Astra) has launched the proton-pump inhibitor esomeprazole (19) (as Nexium) as a treatment for peptic ulcer, gastroesophageal reflux disease, duodenal ulcer, and esophagitis. Esomeprazole is the (S)-enantiomer of omeprazole and was developed as a result of its improved pharmokinetic profile and better potency after oral dosing than (f )-form of omeprazole or the racemate. The dosage is higher than would be expected for a simple chiral switch. The stereogenic center is at sulfur. Detailed accounts of the development of the process have been published.189190... 

Omeprazole (p. 171) can cause maximal inhibition of HC1 secretion. Given orally in gastric juice-resistant capsules, it reaches parietal cells via the blood. In the acidic milieu of the mucosa, an active metabolite is formed and binds covalently to the ATP-driven proton pump (H+/K+-ATPase) that transports H+ in exchange for I<+ into the gastric juice. Lansoprazole, pantoprazole, and rabeprazole produce analogous effects. Omeprazole is a racemate. With respect to dosage, the now available (S)-omeprazole (esomeprazole) represents the more potent enantiomer, but this offers no therapeutic advantage. 

Esomeprazole provided more effective acid control than omeprazole. Both dosages of esomeprazole were well tolerated, and the profile and incidence of adverse events were similar to that observed with omeprazole. The most common were abdominal pain, nausea, diarrhea, respiratory infection, and headache. 

To prevent degradation of proton-pump inhibitors by acid in the gastric lumen, oral dosage forms are supplied in different formulations (1) enteric-coated drugs contained inside gelatin capsules (omeprazole, esomeprazole, and... 

Not understood. A possible explanation is that if the dosage of omeprazole is high enough, it may possibly reduce the metabolism of phenytoin by CYP2C19. However, CYP2C19 has only a minor role in phenytoin metabolism. Esomeprazole may interact similarly. With lansoprazole, the overall picture is that it does not act as an enzyme inducer or inhibitor ... 

Information is limited, but what is eurrentiy known suggests that patients given omeprazole, and possibly esomeprazole, with diazepam may expe-rienee inereased benzodiazepine effeets (sedation, unstable gait ete). If this oeeurs the benzodiazepine dosage should be reduced. Lansoprazole, pantoprazole and rabeprazole do not appear to interaet with diazepam. 

On the right is the plasma level profile of 20 mg omeprazole and 40 mg S-omeprazole after 5 days of dosage. It can be seen that there is an increase in the maximal concentration and dwell time of 40 mg S-omeprazole. The benefit of esomeprazole is due to slower metabolism and therefore longer plasma half-life of this enantiomer. 

To achieve a longer plasma half-life, an enantiomer of omeprazole has been introduced S-omeprazole, esomeprazole. These structures are shown in the figure. This has a slower metabolism than the R-enantiomer and therefore appears to have a longer dwell time in the blood. At 40-mg dosage, there appears to be improvement in pH control as compared to omeprazole as shown in the figure. 

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