Omeprazole

Also indexed as: Losec®, Prilosec®

Omeprazole is a member of the proton pump inhibitor family of drugs, which blocks production of stomach acid. Omeprazole is used to treat diseases in which stomach acid causes damage, including gastric and duodenal ulcers, gastroesophageal reflux disease, erosive esophagitis, and Zollinger-Ellison syndrome.

Safetychecker Summary for Omeprazole
(for details about the summarized interactions, read the full article)

Beneficial May be Beneficial: Depletion or interference—The medication may deplete or interfere with the absorption or function of the nutrient. Taking these nutrients may help replenish them.

Folic acid

Vitamin B12*
Beneficial May be Beneficial: Side effect reduction/prevention—Taking these supplements may help reduce the likelihood and/or severity of a potential side effect caused by the medication.

Cranberry*
Supportive interaction

None known
Reduced drug absorption/bioavailability

None known
Adverse interaction

None known

An asterisk (*) next to an item in the summary indicates that the interaction is supported only by weak, fragmentary, and/or contradictory scientific evidence.

Interactions with Dietary Supplements

Folic acid
Folic acid is needed by the body to utilize vitamin B12. Antacids, including omeprazole, inhibit folic acid absorption.1 People taking antacids are advised to supplement with folic acid.

Vitamin B12
Omeprazole interferes with the absorption of vitamin B12 from food (though not from supplements) in some2 3 4 5 but not all6 7 studies. A true deficiency state, resulting in vitamin B12-deficiency anemia, has only been reported in one case.8 The fall in vitamin B12 status may result from the decrease in stomach acid required for vitamin B12 absorption from food caused by the drug.9 This problem may possibly be averted by drinking acidic juices when eating foods containing vitamin B12.10

However, all people taking omeprazole need to either supplement with vitamin B12 or have their vitamin B12 status checked on a yearly basis. Even relatively small amounts of vitamin B12 such as 10–50 mcg per day, are likely to protect against drug induced vitamin depletion.

Interactions with Herbs

Cranberry (Vaccinium marocarpon)
People taking omeprazole may increase absorption of dietary vitamin B12 by drinking cranberry juice or other acidic liquids with vitamin B12-containing foods.11

References:

1. Russell RM, Golner BB, Krasinski SD, et al. Effect of antacid and H2 receptor antagonists on the intestinal absorption of folic acid. J Lab Clin Med 1988;112:458–63.

2. Marcuard SP, Albernaz L, Khazanie PG. Omeprazole therapy causes malabsorption of cyanocobalamin (Vitamin B12). Ann Intern Med 1994;120:211–5.

3. Termanini B, Gibril F, Sutliff VE, et al. Effect of long-term gastric acid suppressive therapy on serum vitamin B12 levels in patients with Zollinger-Ellison syndrome. Am J Med 1998;104:422–30.

4. Koop H. Review article: metabolic consequences of long-term inhibition of acid secretion by omeprazole. Aliment Pharmacol Ther 1992;6:399–406 [review].

5. Bellou A, Aimone-Gastin I, De Korwin JD, et al. Cobalamin deficiency with megaloblastic anaemia in one patient under long-term omeprazole therapy. J Intern Med 1996;240:161–4.

6. Koop H, Bachem MG. Serum iron, ferritin, and vitamin B12 during prolonged omeprazole therapy. J Clin Gastroenterol 1992;14:288–92.

7. Schenk BE, Festen HP, Kuipers EJ, et al. Effect of short-and long-term treatment with omeprazole on the absorption and serum levels of cobalamin. Aliment Pharmacol Ther 1996;10:541–5.

8. Bellou A, Aimone-Gastin I, De Korwin JD, et al. Cobalamin deficiency with megaloblastic anaemia in one patient under long-term omeprazole therapy. J Intern Med 1996;240:161–4.

9. Saltzman JR, Kemp JA, Golner BB, et al. Effect of hypochlorhydria due to omeprazole treatment or atrophic gastritis on protein-bound vitamin B12 absorption. J Am Coll Nutr 1994;13:584–91.

10. Bradford GS, Taylor CT. Omeprazole and vitamin B12 deficiency. Ann Pharmacother 1999;33:641–3 [review].

11. Saltzman JR, Kemp JA, Golner BB, et al. Effect of hypochlorhydria due to omeprazole treatment or atrophic gastritis on protein-bound vitamin B12 absorption. J Am Coll Nutr 1994;13:584–91.