Should Omeprazole be taken with or without food (before or after)?

Omeprazole is one of the most potent suppressors of gastric acid secretion and inhibitors of the gastric H+, K+-ATPase (proton pump).

In typical doses, it diminishs the daily production of acid (basal and stimulated) by 80-95%.

It is a prodrug that requires activation in an acid environment.

After absorption into the systemic circulation, the prodrug diffuses into the parietal cells of the stomach and accumulates in the acidic secretory canaliculi. Here, it is activated by proton-catalyzed formation of a tetracyclic sulfenamide, trapping the drug so that it cannot diffuse back across the canalicular membrane.

The activated form then binds covalently with sulfhydryl groups of cysteines in the H+, K+-ATPase, irreversibly inactivating the pump molecule.

Because they block the final step in acid production, the proton pump inhibitors are effective in acid suppression regardless of other stimulating factors.

To prevent degradation of proton pump inhibitors by acid in the gastric lumen, oral dosage forms are supplied in different formulations.

The delayed-release and enteric-coated tablets dissolve only at alkaline pH, whereas admixture of omeprazole with sodium bicarbonate simply neutralizes stomach acid; both strategies substantially

improve the oral bioavailability of these acid-labile drugs.

Because an acidic pH in the parietal cell acid canaliculi is required for drug activation and food stimulates acid production, these drugs ideally should be given ~30 minutes before meals.

Concurrent administration of food may reduce somewhat the rate of absorption of proton pump inhibitors, but this effect is not thought to be clinically significant.

Concomitant use of other drugs that inhibit acid secretion, such as H2 receptor antagonists, might be

predicted to lessen the effectiveness of the proton pump inhibitors, but the clinical relevance of this potential interaction is unknown.

In conclusion, although there is no clinical significance in reducing the rate of absorption of omeprazole when it takes together with food, for the best oral bioavailability of it, omeprazole should be taken ~30 minutes before your meals.

Ref: Wallace J.L and Sharkey K.A (2011). Pharmacotherapy of Gastric Acidity, Peptic Ulcers, and Gastroesophageal Reflux Disease. In: Goodman & Gilman’s The Pharmacological Basis of Therapeutics; Ed. Burton L.L, Chabner B.A and Knollmann B. C. 12th Edition. McGraw-Hill Medical Publishing, New York: 1237-1272.