Question

The nurse knows that an important thing to remember about magnesium hydroxide (Milk of Magnesia) is that:

A. this medication may cause constipation
B. This medication may cause a decrease in serum magnesium levels
C. This medication should be avoided in patients with severe renal failure
D. This medication takes several days to work effectively

Answer 1

Magnesium hydroxide, found in Milk of Magnesia, primarily causes a laxative effect, which could lead to diarrhea. It also acts as an antacid by neutralizing stomach acid without producing carbon dioxide. It should be avoided in patients with severe renal failure due to the risk of magnesium accumulation.

Step-by-step explanation:

The nurse should remember that an important thing about magnesium hydroxide (Milk of Magnesia) is that this medication may cause a laxative effect rather than constipation. Magnesium hydroxide works as an antacid and a mild laxative by reacting with the excess stomach acid (HCl) to neutralize it, producing water as a byproduct:

Mg(OH)₂ + 2HCl → MgCl₂ + 2H₂O

This reaction does not produce carbon dioxide. However, magnesium-containing antacids like Milk of Magnesia can cause diarrhea due to their laxative properties. The statement that Milk of Magnesia should be avoided in patients with severe renal failure is correct because the kidneys are responsible for excreting magnesium, and accumulation can occur in the case of renal insufficiency.