Omeprazole

Class

• proton pump inhibitor

Indications

• dyspepsia

• peptic ulcer disease (PUD)

• gastroesophageal reflux disease (GORD/GERD)

• laryngopharyngeal reflux (LPR)

• Zollinger-Ellison syndrome

Administration/Absorption

• • Oral

  • IV

Dosage

Distribution

Mechanism

• reacts with a cysteine group in H⁺/K⁺ ATPase, thereby inhibiting the ability of the parietal cells to produce gastric acid

• omeprazole undergoes a chiral shift in vivo which converts the inactive R-enantiomer to the active S-enantiomer

  • doubles the concentration of the active form

  • accomplished by the CYP2C19 isozyme of cytochrome P450

    • not found equally in all human populations

Excretion

Side effects

• • headache

• diarrhea

  • abdominal pain

• nausea

• dizziness

  • trouble awakening and sleep deprivation

  • hip fractures,^[9][10][11]

  • Clostridium difficile-associated diarrhea

  • bone rebuild interference and B12 vitamin reduction.^[15]

• tubulointerstitial nephritis^[16][17]

  • Link to gastric cancer?

Interactions

• competitive inhibitor of the enzymes CYP2C19 and CYP2C9

Contraindications