Can You Take Magnesium Glycinate 120mg with Bradycardia and Sick Sinus Syndrome?
Yes, you can safely take magnesium glycinate 120mg with bradycardia and sick sinus syndrome—this dose is well below the threshold that affects cardiac conduction, and magnesium does not worsen sinus node dysfunction or bradycardia at physiologic supplementation levels.
Evidence Supporting Safety
Magnesium does not depress sinus node function or worsen bradycardia. The ACC/AHA/HRS guidelines on bradycardia and sick sinus syndrome do not list magnesium among medications that should be avoided or discontinued in patients with sinus node dysfunction 1.
The comprehensive list of contraindicated medications in sick sinus syndrome includes beta-blockers, non-dihydropyridine calcium channel blockers (verapamil, diltiazem), digoxin, Class IC antiarrhythmics, lithium, methyldopa, risperidone, cisplatin, and interferon—but magnesium is notably absent from this list 1, 2.
Intravenous magnesium sulfate at therapeutic doses (10 grams over 6 hours, achieving serum levels of 1.5–2 mmol/L) does not affect heart rate, blood pressure, PR interval, QRS duration, or QT interval in patients with sick sinus syndrome who have pacemakers 3. Your oral dose of 120mg elemental magnesium is far lower than these intravenous therapeutic doses.
Magnesium actually prolongs AV nodal conduction and sinus node refractoriness, but does not cause clinically significant bradycardia or conduction block at therapeutic levels 4. The primary cardiac effects are on ventricular arrhythmias and atrial fibrillation, not on sinus node function 4.
Dosing Context
Your 120mg dose of magnesium glycinate is a standard nutritional supplement dose, far below the intravenous therapeutic doses (several grams) used to treat arrhythmias 3, 4.
Oral magnesium supplementation at this level is used routinely for symptomatic extrasystoles without concern for bradycardia 4.
Medications You Must Avoid
The following medications are contraindicated or should be discontinued in sick sinus syndrome and bradycardia:
- Beta-blockers (e.g., metoprolol, atenolol, carvedilol) 1, 2, 5
- Non-dihydropyridine calcium channel blockers (verapamil, diltiazem) 1, 2, 5
- Digoxin and cardiac glycosides 1, 2, 5
- Class IC antiarrhythmics (flecainide, propafenone) 1, 2
- Amiodarone (unless you have a pacemaker) 1
- Lithium, methyldopa, risperidone 1, 2
Important Caveats
If you are taking any of the contraindicated medications listed above, those should be reviewed with your physician immediately—not the magnesium 1, 2, 5.
Ensure your sick sinus syndrome diagnosis has been confirmed with documented rhythm-symptom correlation on extended cardiac monitoring (≥48 hours), as symptoms alone are nonspecific 1, 6, 7.
Reversible causes of bradycardia (hypothyroidism, electrolyte abnormalities including hypokalemia, hypoxemia, acute infections) should be evaluated and corrected 1, 2.
If you have symptomatic bradycardia or tachy-brady syndrome, the definitive treatment is permanent pacemaker implantation (preferably dual-chamber DDDR), not medication avoidance 1, 6, 8, 7.
Common Pitfall to Avoid
- Do not confuse dihydropyridine calcium channel blockers (amlodipine, nifedipine)—which are safe—with non-dihydropyridine agents (verapamil, diltiazem)—which are contraindicated 2. Magnesium is neither type and does not share their mechanism of sinus node suppression.