Should magnesium glycinate be stopped before surgery in a patient with a history of cardiovascular or respiratory conditions who is undergoing a procedure requiring general anesthesia?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: January 28, 2026 • View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

Should Magnesium Glycinate Be Stopped Before Surgery?

No, magnesium glycinate does not need to be routinely stopped before surgery in most patients, but specific considerations apply for those with cardiovascular or respiratory conditions undergoing general anesthesia.

Key Recommendation

The FDA drug label for magnesium glycinate advises to "consult with your physician if you are undergoing" surgery, but does not mandate discontinuation 1. Current anesthesia guidelines do not specifically require stopping oral magnesium supplements preoperatively 2.

Clinical Context and Rationale

Magnesium's Effects During Anesthesia

Magnesium has several properties relevant to anesthesia:

  • Reduces anesthetic requirements: Perioperative magnesium sulfate decreases propofol needs during induction (-28.52mg) and maintenance (-213.56mg), reduces fentanyl consumption (-53.57 mcg), and decreases neuromuscular blocking agent requirements (-2.99mg) 3.

  • Potentiates neuromuscular blockade: Magnesium blocks acetylcholine release at the motor endplate and potentiates non-depolarizing neuromuscular blockers, which could prolong paralysis 4, 5.

  • Cardiovascular effects: Acts as a vasodilator and reduces catecholamine release during stressful maneuvers like intubation 6, 5.

Risk Stratification

Low-risk patients (no cardiovascular/respiratory disease, normal renal function):

  • Continue magnesium glycinate through surgery 4
  • Standard preoperative fasting guidelines apply 2
  • Inform anesthesiologist of magnesium use to adjust anesthetic dosing 3, 5

High-risk patients (cardiovascular disease, respiratory compromise, renal dysfunction):

  • Consider stopping 24-48 hours before surgery if hypermagnesemia is a concern 4
  • Patients with renal dysfunction are at higher risk for hypermagnesemia, which can cause hypotension, respiratory failure, and cardiac arrest under anesthesia 4
  • Check serum magnesium levels preoperatively if concerned 4

Critical Perioperative Considerations

Anesthetic Implications

  • Reduced drug requirements: Anesthesiologists should anticipate 20-30% reduction in propofol, opioid, and neuromuscular blocker needs 3, 5

  • Prolonged neuromuscular blockade: Ensure train-of-four ratio >0.9 before extubation to confirm complete reversal 7, 5

  • Hypotension risk: Magnesium's vasodilatory effects may cause intraoperative hypotension, particularly in patients with cardiovascular disease 4, 6

Antidote Availability

  • Intravenous calcium is the specific antidote for hypermagnesemia and should be immediately available 4
  • Hypermagnesemia can cause cardiac arrest under anesthesia, particularly in renally impaired patients 4

Common Pitfalls to Avoid

  1. Failing to inform the anesthesiologist: Always disclose magnesium supplementation, as it significantly affects anesthetic dosing 3, 5

  2. Ignoring renal function: Patients with creatinine clearance <30 mL/min require heightened vigilance and may benefit from stopping magnesium 48-72 hours preoperatively 4

  3. Overlooking cardiovascular disease: Patients with pre-existing cardiovascular disease may experience exacerbated hypotension from magnesium's vasodilatory effects 4, 6

  4. Inadequate neuromuscular monitoring: Failure to monitor train-of-four can lead to inadequate reversal and postoperative respiratory complications 5

Practical Algorithm

For patients on magnesium glycinate:

  1. Assess renal function and cardiovascular status

    • Normal renal function + no cardiac disease → Continue magnesium 4, 6
    • CrCl <30 mL/min or significant cardiac disease → Stop 24-48 hours before surgery 4

  2. Inform anesthesia team of magnesium use regardless of continuation decision 3, 5

  3. Intraoperatively: Expect reduced anesthetic requirements and enhanced neuromuscular blockade 3, 5

  4. Before extubation: Confirm train-of-four ratio >0.9 7, 5

  5. Postoperatively: Monitor for residual neuromuscular weakness and respiratory depression 4

References

2
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

4
Research

Magnesium and the anaesthetist.

Canadian journal of anaesthesia = Journal canadien d'anesthesie, 1988

6
Research

Magnesium and anaesthesia.

Current drug targets, 2009

7
Guideline

Anesthetic Management of COL6A+ Bethlem/Ullrich Myopathy

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Related Questions

Does magnesium supplementation help reduce post-operative complications in chronic smokers undergoing anesthesia?
Is it safe to give magnesium after angioplasty (percutaneous coronary intervention) without checking magnesium serum determination in an adult patient with a history of cardiovascular disease and potential impaired renal function?
What are the benefits, dosage, onset, and duration of magnesium sulfate administration during spine surgery, and what parameters should be monitored?
What is the appropriate medication regimen for a patient with bipolar disorder, current episode depressed severe with psychotic features, and a history of cannabis use and alcohol use disorder (AUD)?
What are the treatment options for patellar alta?
What are the treatment options for a patient with plantar fasciitis?
What is the acute treatment for a patient with peripheral vascular disease (PVD) and limb ischemia, with a history of atherosclerotic risk factors such as smoking, diabetes, hypertension, and hyperlipidemia, while awaiting intervention?
Should an 80-year-old patient with hypernatremia be sent to the ER for evaluation and treatment?
What are the differences in treatment approaches using dihydropyridine (DHP) versus nondihydropyridine (non-DHP) calcium channel blockers, such as amlodipine (amlodipine) versus verapamil (verapamil), in patients with hypertension (high blood pressure), angina, arrhythmias, such as atrial fibrillation, heart failure, or impaired renal function (kidney disease)?

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.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.

Ask Question