Esomeprazole

Pharmacogenomic Information in the Context of the FDA-Approved Drug Label*

Esomeprazole is a proton pump inhibitor and entantiomer of omeprazole. It is metabolized in the liver by CYP2C19 and CYP3A4 (see Proton Pump Inhibitor Pathway).

The FDA recommends, but does not require, genetic testing prior to initiating or reinitiating treatment with esomeprazole.

Excerpt from the esomeprazole (Nexium) drug label:
"Esomeprazole may potentially interfere with CYP 2C19, the major esomeprazole metabolizing enzyme. Coadministration of esomeprazole 30 mg and diazepam, a CYP 2C19 substrate, resulted in a 45% decrease in clearance of diazepam. Concomitant administration of esomeprazole and a combined inhibitor of CYP 2C19 and CYP 3A4, such as voriconazole, may result in more than doubling of the esomeprazole exposure. Dose adjustment of esomeprazole is not normally required."

"CYP 2C19 isoenzyme exhibits polymorphism in the metabolism of esomeprazole, since some 3% of Caucasians and 15 to 20% of Asians lack CYP 2C19 and are termed Poor Metabolizers. At steady state, the ratio of AUC in Poor Metabolizers to AUC in the rest of the population (Extensive Metabolizers) is approximately 2."

For the complete drug label text with sections containing pharmacogenetic information highlighted, see the esomeprazole (Nexium) drug label PDF.