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.
Summary of
Interactions with Vitamins, Herbs, and Foods
In some cases, an herb or supplement may appear in more than one category, which may seem
contradictory. For clarification, read the full article for details about the summarized
interactions.
 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. |
Calcium
Folic acid
Vitamin B12*
Vitamin C
|
| 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*
|
Avoid: Reduced drug absorption/bioavailability—Avoid these supplements
when taking this medication since the supplement may decrease the absorption and/or activity
of the medication in the body. |
St. John's wort
|
| Supportive interaction |
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
Calcium
In a study of elderly women, administration of omeprazole decreased the absorption of
calcium,1 presumably because the drug decreased the stomach's production of
hydrochloric acid, which is necessary for calcium absorption. The form of calcium used in the
study to test calcium absorption was calcium carbonate. Drugs that reduce stomach acid
secretion may not inhibit other forms of calcium, such as calcium citrate.2
Folic
acid
Folic acid is needed by the body to utilize
vitamin B12. Antacids, including omeprazole, inhibit folic acid absorption.3
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 some4 5 6 7 but not
all8 9 studies. A true deficiency state, resulting in vitamin
B12-deficiency anemia, has only been reported in one case.10 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.11 This problem may possibly be averted by drinking
acidic juices when eating foods containing vitamin B12.12
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.
Vitamin
C
Treatment of healthy volunteers with omeprazole for four weeks resulted in a 12.3% decrease in
blood levels of vitamin C.13
Interactions with Herbs
St. John's
wort
In a study of healthy human volunteers, supplementing with St. John's wort greatly decreased
omeprazole blood levels by accelerating the metabolism of the drug.14 Use of St.
John's wort may, therefore, interfere with the actions of omeprazole.
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.15
References:1. O'Connell MB, Madden DM, Murray AM, et al. Effects of proton pump
inhibitors on calcium carbonate absorption in women: a randomized crossover trial. Am J
Med 2005;118:778–81.
2. (Recker RR. Calcium absorption and achlorhydria. N Engl J Med
1985;313:70–3.
3. 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.
4. Marcuard SP, Albernaz L, Khazanie PG. Omeprazole therapy causes
malabsorption of cyanocobalamin (Vitamin B12). Ann Intern Med
1994;120:211–5.
5. 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.
6. Koop H. Review article: metabolic consequences of long-term inhibition
of acid secretion by omeprazole. Aliment Pharmacol Ther 1992;6:399–406
[review].
7. 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.
8. Koop H, Bachem MG. Serum iron, ferritin, and vitamin B12 during
prolonged omeprazole therapy. J Clin Gastroenterol 1992;14:288–92.
9. 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.
10. 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.
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.
12. Bradford GS, Taylor CT. Omeprazole and vitamin B12 deficiency.
Ann Pharmacother 1999;33:641–3 [review].
13. Henry EB, Carswell A, Wirz A, et al. Proton pump inhibitors reduce
the bioavailability of dietary vitamin C. Aliment Pharmacol Ther
2005;22:539–5.
14. Wang LS, Zhou G, Zhu B, et al. St John's wort induces both cytochrome
P450 3A4-catalyzed sulfoxidation and 2C19-dependent hydroxylation of omeprazole. Clin
Pharmacol Ther 2004;75:191–7.
15. 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.