Zefxon Mechanism of Action

Pharmacology: Pharmacodynamics: Omeprazole (Zefxon) injection is the proton acid pump inhibitor which reduces gastric acid secretion by specific action; inhibition of the enzyme H⁺, K⁺-ATPase (The proton pump) in the parietal cell, the final step of acid secretion; thus inhibition of acid secretion occurs.
Pharmacokinetics: Distribution: The apparent volume of distribution in healthy subjects is approximately 0.3 L/kg and a similar value is also seen in patients with renal insufficiency. In the elderly and in patients with hepatic insufficiency, the volume of distribution is slightly decreased. The plasma protein binding of omeprazole is about 95%.
Metabolism and excretion: The average half-life of the terminal phase of the plasma concentration-time curve following IV administration of omeprazole is approximately 40 minutes; the total plasma clearance is 0.3 to 0.6 L/min. There is no change in half-life during treatment.
Omeprazole is completely metabolised by the cytochrome P450 system, mainly in the liver.
No metabolite has been found to have any effect on gastric acid secretion. Almost 80% of an intravenously given dose is excreted as metabolites in the urine, and the remainder is found in the faeces, primarily originating from biliary secretion.
Elimination of omeprazole is unchanged in patients with reduced renal function. The elimination half-life is increased in patients with impaired liver function, but omeprazole has not shown any accumulation with once daily oral dosing.