Adults

For erosive esophagitis: 20 mg or 40 mg once daily for 4-8 weeks. For symptomatic GERD: 20 mg once daily for 4 weeks. For H. pylori eradication: 40 mg once daily for 10 days with appropriate antibiotics. For NSAID-associated ulcers: 20 mg once daily for 4-8 weeks. For Zollinger-Ellison Syndrome: Initial dose 40 mg twice daily, adjusted as needed.

Elderly

No dosage adjustment is generally required in elderly patients.

Renal_impairment

No dosage adjustment is necessary for patients with impaired renal function.

Onset

Acid secretion inhibition occurs within 1 hour after a single oral dose.

Excretion

Approximately 80% of metabolites are excreted in the urine and 20% in the feces.

Half life

Plasma elimination half-life is approximately 1-1.5 hours.

Absorption

Rapidly absorbed after oral administration, bioavailability is about 50-68% (increasing with repeated dosing to 89%). Peak plasma concentration is reached within 1-2 hours.

Metabolism

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

Warfarin

May increase INR and prothrombin time, monitor for bleeding.

Clopidogrel

Reduced antiplatelet effect of clopidogrel due to CYP2C19 inhibition.

Methotrexate

May increase serum levels of methotrexate, particularly with high doses.

Atazanavir/Nelfinavir

Reduced plasma concentrations of these antivirals; concomitant use contraindicated with nelfinavir.

Ketoconazole/Itraconazole/Erlotinib

Reduced absorption due to increased gastric pH.