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 12 supplements. They can be absorbed easily because they are not attached to proteins.



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.



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.



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.