Magnesium replacement targets for people in the ICU

Effect of Protocolized Magnesium Replacement in Critically Ill Patients on Mortality and Atrial Fibrillation: the MAGNOLIA Randomized Controlled Trial

PHASE4 · Scarborough General Hospital · NCT07173855

This trial will test whether keeping ICU patients' magnesium levels to a higher target versus a lower target leads to better 30-day survival and fewer episodes of atrial fibrillation.

Quick facts

PhasePHASE4
Study typeInterventional
Enrollment3253 (estimated)
Ages16 Years and up
SexAll
SponsorScarborough General Hospital (other)
Locations6 sites (Ajax, Ontario and 5 other locations)
Trial IDNCT07173855 on ClinicalTrials.gov

What this trial studies

This is a multi-center, open-label, randomized trial embedded in the shared electronic medical record at participating hospitals in Ontario, comparing a higher magnesium replacement target (>0.95 mmol/L) to a lower target (>0.7 mmol/L) for adults admitted to medical-surgical ICUs. Patients aged 16 and older who have an order for the magnesium replacement protocol are randomized to one of the two target strategies and receive magnesium supplementation per the assigned protocol. The primary outcome is an ordinal composite at 30 days combining death and the number of ICU days free of atrial fibrillation or flutter; secondary outcomes include ventricular arrhythmia, use of antiarrhythmics, vasopressor and ventilator use, new renal replacement therapy, lengths of stay, and magnesium dosing and levels. Analyses use an intention-to-treat approach with Bayesian regression and weakly skeptical priors.

Who should consider this trial

Good fit: Adults aged 16 or older admitted to a participating medical-surgical ICU who have an order for the magnesium replacement protocol and do not meet exclusion criteria are eligible.

Not a fit: Patients with pre-eclampsia, sustained ventricular tachycardia, neuromuscular junction disorders like myasthenia gravis, or those not admitted to participating hospitals are excluded and would not receive benefit from this protocol.

Why it matters

Potential benefit: If successful, this approach could reduce deaths or atrial fibrillation in critically ill patients by identifying the better magnesium target for routine ICU care.

How similar studies have performed: Some prior trials have shown magnesium can reduce arrhythmias in specific settings such as cardiac surgery, but protocolized magnesium targets across general ICU populations remain novel and not proven in large randomized trials.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Age 16 years or older
* Admission orders written to a medical-surgical intensive care unit at a participating site
* Magnesium replacement protocol ordered

Exclusion Criteria:

* Prior enrollment in or withdrawal from MAGNOLIA trial
* Sustained ventricular tachycardia
* Pre-eclampsia
* Myasthenia gravis

Where this trial is running

Ajax, Ontario and 5 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Critical Illness, Critical illness, Magnesium, Atrial fibrillation, Protocols

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.