Adults

For GERD: 20-40 mg once daily for 4-8 weeks. For H. pylori eradication: 40 mg once daily for 10 days with appropriate antibiotics. For Zollinger-Ellison syndrome: Initial dose 40 mg twice daily, adjusted as needed.

Elderly

No specific dosage adjustment is generally required for elderly patients with normal renal and hepatic function.

Renal_impairment

No dosage adjustment is needed for patients with renal impairment.

Onset

Within 1 hour.

Excretion

Approximately 80% of the dose is excreted as metabolites in the urine, and the remainder in the feces.

Half life

Approximately 1-1.5 hours.

Absorption

Rapidly absorbed after oral administration, peak plasma concentrations occur within 1-2 hours. Bioavailability is about 64% after a single 40 mg dose, increasing to 89% after repeated once-daily dosing.

Metabolism

Extensively metabolized in the liver by the cytochrome P450 (CYP) enzyme system, primarily by CYP2C19 and to a lesser extent by CYP3A4.

Warfarin

Increased INR and prothrombin time, monitor closely.

Clopidogrel

Potential reduction in antiplatelet effect, use with caution.

Methotrexate

Increased methotrexate levels, especially with high doses.

Nelfinavir, Atazanavir

Reduced plasma concentrations of antiretrovirals, avoid concomitant use.

Diazepam, Citalopram, Imipramine, Phenytoin

Esomeprazole can inhibit the metabolism of drugs metabolized by CYP2C19, potentially increasing their levels.