Drug Interactions:

Antacids

The term "antacid" is used to describe certain compounds that directly neutralize stomach acid. Tums, Maalox, and Mylanta all fall into this category. The active ingredients in most antacids are various forms of calcium, magnesium, and aluminum. Antacids are useful mostly for symptomatic relief of uncomfortable "acid stomach" and may also be helpful for heartburn.

Many antacids are available today, including

• aluminum carbonate (Basaljel)
• aluminum hydroxide (ALternaGEL, Alu-Cap, Alu-Tab, Amphojel, Dialume, Nephrox)
• aluminum hydroxide/magnesium carbonate (Duracid)
• aluminum hydroxide/magnesium hydroxide (Alamag, Almacone, Aludrox, Gaviscon Liquid, Gelusil, Kudrox, Maalox, Magalox, Magnox, Mintox, Mylanta, Rulox)
• aluminum hydroxide/magnesium hydroxide/calcium carbonate (Tempo)
• aluminum hydroxide/magnesium trisilicate (Alenic Alka, Gaviscon, Genaton, Foamicon)
• calcium carbonate (Alkets, Amitone, Chooz, Equilet, Gas-Ban, Maalox Antacid Caplets, Mallamint, Mylanta Lozenges, Titralac, Tums)
• calcium carbonate/magnesium carbonate (Marblen, Mi-Acid Gelcaps, Mylanta Gelcaps, Mylagen Gelcaps)
• magnesium hydroxide (Milk of Magnesia, Phillips' Chewable)
• magaldrate or aluminum magnesium hydroxide sulfate (Iosopan, Riopan)
• magnesium oxide (Mag-Ox, Maox, Uro-Mag)
• sodium bicarbonate (Bell/ans, Bromo Seltzer)
• sodium citrate (Citra pH)

Other drugs work by reducing the stomach's production of acid. These are discussed separately in the articles on H₂ Blockers (e.g., Zantac [ranitidine], Axid [nizatidine], Tagamet [cimetidine], Pepcid [famotidine]) and Proton Pump Inhibitors (Prilosec [omeprazole], Prevacid [lansoprazole]). These drugs produce a more powerful effect than antacids and are used for ulcers as well as for the treatment of esophageal reflux, commonly known as heartburn.

Folate

Supplementation Possibly Helpful

Research suggests that antacids physically bind to folate and reduce its absorption by the body.¹ However, the decrease in folate absorption is relatively small, and this interaction may be clinically significant only in individuals who take antacids regularly and whose diets are low in folate content.

Minerals

Supplementation Possibly Helpful, but Take at a Different Time of Day

Different types of antacids can interfere with the absorption of various minerals. Supplements containing the U.S. Dietary Reference Intake (formerly known as the Recommended Dietary Allowance) of these minerals should be helpful, especially if you take them at a different time of day from when you take antacids, at least 2 hours before or after taking your antacid.

Any antacid can interfere with the absorption of iron, zinc, and possibly other minerals by neutralizing stomach acid. ²

Aluminum-containing antacids can bind with phosphorus and interfere with its absorption, and this can further lead to calcium depletion.^3,4

Antacids that contain calcium may also compete for absorption with iron.^5–9 Although calcium antacids may alter the absorption of magnesium, the clinical importance of this effect appears to be minimal.^10,11 Calcium-containing antacids, when taken with zinc supplements, might substantially decrease zinc absorption.^12–16 However, the presence of a meal appears to mitigate this effect. Finally, calcium antacids might also impair the absorption of manganese and chromium.

^17,18,19

Citrate

May Increase Aluminum Absorption

Concerns have been raised that the aluminum in some antacids may not be good for you.²⁰ Since there is some evidence that calcium citrate supplements might increase the absorption of aluminum,^21–25 it might not be a good idea to take calcium citrate at the same time of day as aluminum-containing antacids. Another option is to use other forms of calcium, or to avoid antacids containing aluminum.

Last reviewed March 2002 by Medical Review Board

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