Should I Stop Taking Magnesium Before Surgery?

When It Makes Sense

• Good fit: If your surgeon or anesthesiologist has specifically advised stopping magnesium because it may interact with certain muscle relaxants or affect blood pressure, pausing the supplement in the days before surgery is reasonable.
• Good fit: When you are taking a high dose of magnesium (more than the typical dietary amount) and have a history of kidney impairment, stopping the supplement reduces the risk of excess magnesium levels during anesthesia.

When You Should Avoid It

• Warning sign: If you rely on magnesium to control a diagnosed condition such as severe migraine, arrhythmia, or pre‑eclampsia, stopping abruptly could worsen your condition and create a greater peri‑operative risk.
• Warning sign: When you have no specific medical instruction and are using a low, dietary‑level dose, withholding it may provide no clear benefit and could lead to unnecessary electrolyte imbalance.

Pros and Cons

Pros

• Potentially reduces the chance of magnesium‑related interaction with anesthetic agents that influence neuromuscular blockade.
• Provides a clear, documented medication‑free window for the surgical team, simplifying pre‑operative assessment.

Cons

• If magnesium is part of a regimen that manages blood pressure or heart rhythm, stopping it may create a rebound effect, increasing peri‑operative cardiovascular risk.
• Discontinuation may cause withdrawal symptoms such as muscle cramps, insomnia, or worsening of chronic migraine, adding discomfort before surgery.

Decision Checklist

• Has your surgeon, anesthesiologist, or primary care physician specifically instructed you to stop magnesium?
• Are you taking magnesium at a therapeutic dose for a medical condition that could become unstable if the supplement is stopped?
• Do you have normal kidney function and are you using a low‑dose supplement that is unlikely to affect anesthesia?

Alternatives to Consider

Instead of stopping magnesium completely, you might discuss with your care team the possibility of reducing the dose, switching to a form with lower bioavailability, or timing the last dose several hours before anesthesia. In some cases, a brief blood test to check serum magnesium can guide whether continuation is safe.

Final Recommendation

For most healthy adults taking modest over‑the‑counter magnesium, there is generally no need to stop unless a clinician advises otherwise. If you have a medical condition managed by magnesium, have kidney issues, or have received a direct instruction from your surgical team, pause the supplement as directed. Always confirm the plan with your surgeon or anesthesiologist before making any changes.