Medically Reviewed on 5/2/2022

Generic Name: magaldrate

Brand and Other Names: Riopan, Maalox (discontinued), aluminum hydroxide/magnesium hydroxide

Drug Class: Antacids, Combos

What is magaldrate, and what is it used for?

Magaldrate is an over-the-counter medication commonly used to treat gastrointestinal (GI) issues from acidity including heartburn, acid indigestion, gastroesophageal reflux, gastric and duodenal ulcers. Magaldrate is an antacid that neutralizes the stomach acid and protects the GI lining from its corrosive effects. Magaldrate may be combined with simethicone which reduces flatulence. Magaldrate may also be used to treat magnesium deficiency and to reduce high blood phosphate levels (hyperphosphatemia).

Magaldrate is a combination drug with variable compositions of two antacids, rapid-acting magnesium hydroxide and slow-acting aluminum hydroxide. Magaldrate rapidly reacts with stomach acid, neutralizing it, and releases aluminum hydroxide which sustains the neutralizing activity. Aluminum hydroxide is an astringent that can cause constipation and this effect is balanced by magnesium hydroxide which has laxative properties. Currently, magaldrate is discontinued in the United States.


  • Do not use magaldrate in patients with hypersensitivity to magaldrate or any of its components
  • Do not use magaldrate to treat debilitated patients or patients with kidney function impairment
  • Do not use magaldrate to treat patients with abdominal pain and/or at risk for bowel obstruction
  • Prolonged magaldrate use may cause low blood phosphate levels (hypophosphatemia), which may lead to loss of appetite (anorexia), weakness and softening of bones (osteomalacia); use with caution
  • Magaldrate can cause high magnesium levels (hypermagnesemia) or aluminum intoxication, especially in patients with renal insufficiency; may lead to osteomalacia and dialysis encephalopathy, an aluminum-related brain damage
  • May increase or decrease the rate of absorption of other oral drugs administered concurrently
  • Some formulations may contain propylene glycol which is toxic in large amounts

What are the side effects of magaldrate?

Common side effects of magaldrate include:

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug.

Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.


GERD is the back up of stomach acid into the esophagus. See Answer

What are the dosages of magaldrate?

Oral suspension

  • (500mg/500mg)/5mL

Oral liquid

  • (200mg/200mg)/5mL


Heartburn, Sour Stomach, and Acid Indigestion

  • 5-10 mL (1-2 teaspoonfuls; 540-1080 mg) between meals and at bedtime; not to exceed 80 mL (16 teaspoonfuls) in 24-hour period

Other Indications and Uses


  • Children younger than 12 years: Safety and efficacy not established
  • Children older than 12 years: 10-20 mL orally between meals and at bedtime


  • Magaldrate overdose is unlikely to cause serious reactions. Overdose may be treated with discontinuation of magaldrate and symptomatic care.
  • In case of overdose, seek medical help or contact Poison Control.

What drugs interact with magaldrate?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

  • Severe interactions of magaldrate include:
  • Magaldrate has serious interactions with at least 33 different drugs.
  • Magaldrate has moderate interactions with at least 132 different drugs.
  • Magaldrate has mild interactions with at least 59 different drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

Pregnancy and breastfeeding

  • There are no well-controlled studies on magaldrate use in pregnancy; it is not recommended for use in the first trimester of pregnancy and may be used with caution after, if benefits outweigh potential risks
  • It is not known if magaldrate is present in breast milk; use with caution in nursing mothers

What else should I know about magaldrate?

  • Take magaldrate exactly as per labeled directions
  • Check with your doctor before taking magaldrate if you are on a sodium or magnesium-restricted diet; do not take for longer than 14 days
  • Store safely out of reach of children



Magaldrate is an over-the-counter medication commonly used to treat gastrointestinal (GI) issues from acidity including heartburn, acid indigestion, gastroesophageal reflux, gastric and duodenal ulcers. Common side effects of magaldrate include chalky taste, stomach cramps, fecal discoloration, constipation, fecal impaction, nausea, vomiting, osteomalacia, aluminum intoxication (hyperaluminemia), hypophosphatemia, hypermagnesemia, and diarrhea.

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically Reviewed on 5/2/2022