Download H2 Blockers

| Drug Interactions:
H2 Blockers
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Vitamin B12 - Probable Need for Supplementation | Folate - Supplementation Possibly Helpful | Minerals Supplementation Possibly Helpful | Magnesium - Take at a Different Time of Day | Vitamin D - Possible
Inhibition by Cimetidine
Medications in this family sharply decrease stomach acid production. They are widely used for the treatment of
ulcers as well as for mild cases of esophageal reflux (heartburn).
Drugs that fall into this family include
cimetidine (Tagamet, Tagamet HB)
famotidine (Pepcid, Pepcid AC, Pepcid RPD)
nizatidine (Axid, Axid AR)
ranitidine hydrochloride (Zantac, Zantac EFFERdose, Zantac GELdose, Zantac 75)
and others
Vitamin B12
Probable Need for Supplementation
H 2 -receptor blockers appear to impair the absorption of vitamin B 12 from food. 1,2,3 This is thought to occur
because the vitamin B 12 in food is attached to proteins. Stomach acid separates them and allows the B 12 to be
absorbed.
The solution? If you regularly use H 2 blockers, take B
are not attached to proteins.
12
supplements. They can be absorbed easily because they
Folate
Supplementation Possibly Helpful
There is some evidence that H 2 blockers may slightly reduce the absorption of folate. 4 Folate is an important
nutrient and one that is commonly deficient in the diet; so if you are taking H 2 blockers, you should probably
take folate supplements, too.
Minerals
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Supplementation Possibly Helpful
By reducing stomach acid levels, H 2 blockers might interfere with the absorption of iron, zinc, and perhaps other
minerals.5–8 Taking mineral supplements that provide the U.S. Dietary Reference Intake (formerly known as the
Recommended Dietary Allowance) of these substances should help.
Magnesium
Take at a Different Time of Day
Magnesium supplements may interfere with the absorption of H 2 blockers.9 However, the interference may be
too minor to cause a real problem. If you think your magnesium supplements are interfering with your
medication, you can get around the problem by taking these minerals at least 2 hours before or after you take an
H 2 -blocking medication.
Vitamin D
Possible Inhibition by Cimetidine
Cimetidine may interfere with vitamin D metabolism. 10,11,12 Other H 2 blockers may not interact. Whether taking
more vitamin D is useful remains unknown.
References [ + ]
1. Salom IL, Silvis SE, Doscherholmen A. Effect of cimetidine on the absorption of vitamin B
Gastroenterol 17: 129–131, 1982.
12.
Scand J
2. Streeter AM, Goulston KJ, Bathur FA, et al. Cimetidine and malabsorption of cobalamin. Dig Dis Sci 27:
13–16, 1982.
3. Blache J, Zittoun J, Marquet J, et al. Effect of ranitidine on secretion of gastric intrinsic factor and absorption
of vitamin B 12. Gastroenterol Clin Biol 7: 381–384, 1983.
4. Russell RM, Golner BB, Krasinski SD, et al. Effect of antacid and H
absorption of folic acid. J Lab Clin Med 112: 458–463, 1988.
2
receptor antagonists on the intestinal
5. D'Arcy PF and McElnay JC. Drug interactions in the gut involving metal ions. Rev DrugMetabol Drug Interact
5(2–3):83–112, 1985.
6. Hathcock JN. Metabolic mechanisms of drug-nutrient interactions. Fed Proc 44(1): 124, 1985.
7. Sturniolo GC, et al. Inhibition of gastric acid secretion reduces zinc absorption in man. JAm Coll Nutr 4:
372–375, 1991.
8. Aymard JP, Aymard B, Netter P, et al. Haematological adverse effects of histamine H
Med Toxicol Adverse Drug Exp 3: 430–448, 1988.
9. Bachmann KA, Sullivan TJ, Jauregui L, et al. Drug interactions of H
2
2
-receptor antagonists.
-receptor antagonists. Scand J
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Gastroenterol Suppl 206: 14–19, 1994.
10. Bengoa JM, et al. Hepatic vitamin D 25-hydroxylase inhibition by cimetidine and isoniazid. J Lab Clin Med
104: 546–552, 1984.
11. Anonymous. Cimetidine inhibits the hepatic hydroxylation of vitamin D. Nutr Rev 43: 184–185, 1985.
12. Odes HS. Effect of cimetidine on hepatic vitamin D metabolism in humans. Digestion 46(2): 61–64, 1990.
Last reviewed August 2011 by EBSCO CAM Review Board
Last Updated: 8/1/2011
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