Also indexed as: Mylanta-AR, Pepcid, Pepcid AC
About famotidine
Famotidine is a member of the H-2 blocker (histamine blocker) family of drugs that prevents
the release of acid into the stomach. Famotidine is used to treat stomach and duodenal ulcers, reflux of stomach acid into the
esophagus, and Zollinger-Ellison syndrome. Famotidine is available as a prescription drug and
as a nonprescription product for relief of
heartburn, acid indigestion, and sour
stomach.
Helpful Products
Try these helpful products which may be beneficial if taken with this medicine
- Iron
- Preliminary research suggests that taking acid-reducing drugs might cause iron deficiency
due to reduced absorption; to avoid deficiency, consider eating more foods that contain iron,
such as oysters, meat, poultry, and fish
- Vitamin B12
- To avoid depleting this nutrient, which might lead to anemia and high homocysteine blood
levels, supplement with 1,000 mcg of vitamin B12 per day
These recommendations are not comprehensive and are not intended to
replace the advice of your doctor or pharmacist. Continue reading the full article for more
information on interactions with vitamins, herbs, and foods.
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. |
Iron*
Vitamin B12
|
Avoid: Adverse interaction—Avoid these supplements when taking this
medication because taking them together may cause undesirable or dangerous results. |
Tobacco
|
Check: Other—Before taking any of these supplements or eating any of
these foods with your medication, read this article in full for details. |
Copper
Folic acid
Magnesium
|
| Side effect reduction/prevention |
None known
|
| Supportive interaction |
None known
|
| Reduced drug
absorption/bioavailability |
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
Iron
Stomach acid may increase absorption of iron from food. H-2 blocker drugs reduce stomach acid
and are associated with decreased dietary iron absorption.1 The iron found in
supplements is available to the body without the need for stomach acid. People with ulcers may
be iron deficient due to blood loss. If iron
deficiency is present, iron supplementation may be beneficial. Iron levels in the blood can be
checked with lab tests.
Magnesium-containing antacids
In healthy people, a magnesium hydroxide/aluminum hydroxide antacid, taken with
famotidine, decreased famotidine absorption by 20–25%.2 People can avoid this
interaction by taking famotidine two hours before or after any aluminum/magnesium-containing
antacids. Some magnesium supplements such as
magnesium hydroxide are also antacids.
Vitamin
B12
Stomach acid is needed for the vitamin B12 in food to be absorbed. H-2 blocker drugs reduce
stomach acid and may therefore inhibit absorption of the vitamin B12 naturally present in
food. However, the vitamin B12 found in supplements does not depend on stomach acid for
absorption.3 Lab tests can determine vitamin B12 levels in people.
Other vitamins and minerals
Some evidence indicates that other vitamins and minerals, such as folic acid4 and copper,5 require the presence of stomach
acid for optimal absorption. Long-term use of H-2 blockers may therefore promote a deficiency
of these nutrients. Individuals requiring long-term use of H-2 blockers may therefore benefit
from a multiple vitamin/mineral
supplement.
Interactions with Foods and Other Compounds
Food
Famotidine may be taken with or without food.6 To prevent heartburn after meals,
famotidine is best taken one hour before meals.7
Tobacco
In a study of 18 healthy people, cigarette smoking was found to decrease the acid blocking
effects of famotidine.8 A double-blind, randomized study of 594 patients with
duodenal ulcers found that smoking inhibited the ulcer-healing effect of
famotidine.9
References:1. Aymard JP, Aymard B, Netter P, et al. Haematological adverse effects
of histamine H2-receptor antagonists. Med Toxicol Adverse Drug Exp
1988;3:430–48.
2. Bachmann KA, Sullivan TJ, Jauregui L, et al. Drug interactions of
H2-receptor antagonists. Scand J Gastroenterol Suppl 1994;206:14–9.
3. Aymard JP, Aymard B, Netter P, et al. Haematological adverse effects
of histamine H2-receptor antagonists. Med Toxicol Adverse Drug Exp
1988;3:430–48.
4. Russell RM, Krasinski SD, Samloff IM. Correction of impaired folic
acid (Pte Glu) absorption by orally administered HCl in subjects with gastric atrophy. Am
J Clin Nutr 1984;39:656.
5. Tompsett SL. Factors influencing the absorption of iron and copper
from the alimentary tract. Biochem J 1940;34:961–9.
6. Lin JH, Chremos AN, Kanovsky SM, et al. Effects of antacids and food
on absorption of famotidine. Br J Clin Pharmacol 1987;24:551–3.
7. Threlkeld DS, ed. Gastrointestinal Drugs, Histamine H2 Antagonists,
Famotidine. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and
Comparisons, Sep 1995, 305f–5g.
8. Schurer-Maly CC, Varga L, Koelz HR, Halter F. Smoking and pH response
to H2-receptor antagonists. Scand J Gastroenterol 1989;24:1172–8.
9. Reynolds JC, Schoen RE, Maislin G, Zangari GG. Risk factors for
delayed healing of duodenal ulcers treated with famotidine and ranitidine. Am J
Gastroenterol 1994;89:571–80.