Drug Interaction Between Milk Of Magnesia And Pepcid

In our latest question and answer, the pharmacist discusses whether or not there is a drug interaction between Milk of Magnesia and Pepcid (famotidine).

Jul 07, 2018

Jul asked

Can you take Milk of Magnesia with Pepcid?


Milk of Magnesia (magnesium hydroxide) and Pepcid (famotidine) are safe to take together. There is no interaction between the two products. In fact, there may be beneficial effects of using both together.

While both Pepcid and Milk of Magnesia are antacids, they have a different mechanism of action and can be used simultaneously. Milk of Magnesia is a faster acting antacid, that works by reacting with gastric acid in the stomach (forming magnesium chloride and water), neutralizing the acid and reliving symptoms such as heartburn and abdominal pain. Best effects are seen if Milk of Magnesia is taken with a meal, or within 30 minutes after eating.

Pepcid doesn't directly neutralize stomach acid, but works to decrease gastric acid secretion in the stomach by binding to histamine-2 (H2) receptors on parietal cells (i.e. acid producing cells) in the stomach.

Milk of Magnesia and Pepcid can work synergistically together, decreasing stomach acid secretion as well as neutralizing the acid that is secreted. You can feel safe taking both together.

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