What are the contraindications for milk of magnesia?

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Last updated: June 26, 2025View editorial policy

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From the Guidelines

Milk of magnesia is contraindicated in individuals with significant renal impairment, particularly those with a creatinine clearance of <20 mg/dL, due to the risk of hypermagnesemia 1. The primary concern with using milk of magnesia is the potential for magnesium accumulation in individuals with kidney disease, which can lead to hypermagnesemia and worsen morbidity and mortality outcomes.

  • Key contraindications for milk of magnesia include:
    • Renal insufficiency or significant renal impairment
    • Intestinal obstruction
    • Severe abdominal pain, nausea, vomiting, or symptoms of appendicitis
    • Myasthenia gravis, as it may worsen muscle weakness
    • Heart block or irregular heartbeats, due to potential magnesium toxicity effects on cardiac function
    • Rectal bleeding or inflammatory bowel conditions like Crohn's disease or ulcerative colitis
    • Magnesium sensitivity or those on a magnesium-restricted diet
    • Patients taking certain medications, such as some antibiotics (like tetracyclines and fluoroquinolones), digoxin, or bisphosphonates, as it can interfere with absorption. It is essential to consider these contraindications to minimize the risk of adverse effects and ensure the best possible outcomes in terms of morbidity, mortality, and quality of life 1.

From the Research

Contraindications for Milk of Magnesia

The following are contraindications for milk of magnesia:

  • Renal failure: Patients with renal failure are at risk of developing severe symptomatic hypermagnesemia when using milk of magnesia or other magnesium-containing products 2, 3.
  • Bowel disorders: Patients with bowel disorders, such as sigmoid volvulus, are also at risk of developing severe symptomatic hypermagnesemia when using milk of magnesia 2.
  • Normal renal function with bowel obstruction: Even patients with normal renal function can develop hypermagnesemia if they have a bowel obstruction and are taking magnesium hydroxide 4.
  • Elderly patients: Elderly patients are at higher risk of developing severe symptomatic hypermagnesemia due to decreased renal function and other comorbidities 2, 3.

Special Considerations

  • Patients with significant renal dysfunction should be aware of the risk of severe hypermagnesemia when using milk of magnesia or other magnesium-containing products 3.
  • Patients using magnesium-containing medications for relief of gastrointestinal distress may be at increased risk for hypermagnesemia 4.
  • Excessive ingestion of magnesium hydroxide can lead to paradoxical hypomagnesemia due to massive diarrhea 5.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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