Can I take magnesium glycinate 120 mg with sick sinus syndrome-associated bradycardia?

Magnesium Glycinate 120 mg is Safe in Sick Sinus Syndrome

Magnesium glycinate 120 mg can be safely taken in patients with sick sinus syndrome and bradycardia, as magnesium supplements are not listed among medications that cause or exacerbate sinus node dysfunction. 1

Medications to Avoid in Sick Sinus Syndrome

The ACC/AHA/HRS guidelines explicitly identify drugs that must be eliminated in patients with sick sinus syndrome because they directly depress sinus node function: 2, 1

• Beta-blockers are contraindicated and should be discontinued 1
• Non-dihydropyridine calcium channel blockers (verapamil, diltiazem) are contraindicated unless a functioning pacemaker is already in place 1
• Digoxin and cardiac glycosides must be avoided as they exacerbate sinus node dysfunction 1
• Class IC antiarrhythmic agents and other membrane-active antiarrhythmics should be eliminated 1
• Other agents including lithium, methyldopa, risperidone, cisplatin, and interferon can worsen bradycardia 2, 1

Why Magnesium is Safe

Magnesium supplements, including magnesium glycinate, do not appear on the comprehensive list of medications that cause or worsen sinus node dysfunction in the 2018 ACC/AHA/HRS bradycardia guidelines. 2, 1 The systematic medication review algorithm for sick sinus syndrome specifically targets agents that depress sinus node activity, and magnesium is not among them. 1

Important Distinction: Dihydropyridine vs Non-Dihydropyridine Calcium Channel Blockers

A common pitfall is confusing different classes of calcium channel blockers: 1

• Dihydropyridine agents (amlodipine, nifedipine) are safe in sick sinus syndrome
• Non-dihydropyridine agents (verapamil, diltiazem) are contraindicated

Magnesium does not function as a calcium channel blocker in the same manner as these pharmaceutical agents and does not suppress sinus node automaticity. 2

Management Algorithm for Sick Sinus Syndrome

Before attributing symptoms to intrinsic sinus node disease, the guidelines recommend: 2, 1

1. First step: Systematically review and eliminate all medications that depress sinus node activity (beta-blockers, non-dihydropyridine calcium channel blockers, digoxin, antiarrhythmics) 1

2. Second step: Assess for reversible metabolic contributors including hypothyroidism, electrolyte disturbances (potassium abnormalities), hypoxemia, and acute infections 2, 1

3. Third step: If symptoms persist after addressing reversible causes and the patient has documented symptomatic bradycardia, permanent pacemaker implantation becomes the definitive therapy 2, 3

Clinical Context

The 120 mg dose of magnesium glycinate is a modest supplemental dose, well below levels that would cause systemic effects on cardiac conduction. 2 Magnesium deficiency itself can contribute to arrhythmias, and maintaining adequate magnesium levels is generally beneficial for cardiac health without suppressing sinus node function. 2

In summary, you can safely continue magnesium glycinate 120 mg with sick sinus syndrome, but ensure you are not taking any of the contraindicated medications listed above. 1