Name: Omeprazole (Prilosec)
Class: Proton Pump Inhibitor
Mechanism: Irreversible inhib. of H+/K+ ATPase ® > 95% inhib. of acid secretion.
Absorption: Oral ® 30-40% bioavail. Peak plasma levels at 0.5-3.5 hr. Give prior to meals, preferably in the morning. Additional dose, if necessary, should be given later in the day.
Dist.:
Metabolism.:
Excretion, t½: 0.5-1 hr.
Toxicity/S.E.s: Rare headache, diarrhea, rash. Inhib. of cyt. P-450 requires altered doses of warfarin, phenytoin, diazepam, and cyclosporin. Inhib. of vitamin. B12 absorption.
Utility: PUD, erosive esophagitis, Zollinger-Ellison synd., GERD.
Special Features: Mismatch between pharmacokinetics & pharmacodynamics. Short t½, but actions last > 24 hr (irreversible binding). Acid inhib. ® gastrin.