Congestive Heart Failure (CHF) and Magnesium

There is some evidence that supplementing with magnesium may be helpful for individuals taking both digoxin and diuretics; diuretics can deplete the body of magnesium and this in turn may increase risk of digoxin side effects.^48-52 Other studies suggest that supplementing with magnesium may offer an array of other benefits for patients with congestive heart failure (CHF).

Magnesium may have many beneficial effects on the heart. Our bodies need mangesium for healthy functioning, including muscle relaxation, blood clotting, and the manufacture of ATP (adenosine triphosphate, the body's main energy molecule).

People with congestive heart failure often take drugs (loop diuretics) that deplete magnesium. The combination of magnesium deficiency with digoxin (another drug given for CHF) may cause arrhythmias. Thus, it is possible that some patients benefit from magnesium supplementation because it corrects this depletion.

It has been called "nature's calcium channel blocker." The idea refers to magnesium's ability to block calcium from entering muscle and heart cells. A group of prescription heart medications work in a similar way, although much more powerfully. This may be the basis for some of magnesium's effects when it is taken as a supplement in fairly high doses.

Read more details about Magnesium.

One study found that use of magnesium (as magnesium orotate) may improve exercise capacity and reduce heart arrhythmias in people with CHF who have just undergone bypass graft surgery.⁵⁷ Additionally, in a well-designed trial involving 79 patients with severe congestive heart failure, magnesium orotate significantly improved survival and clinical symptoms after one year compared to a placebo.⁶³

A typical supplemental dosage of magnesium goes up to 600 mg daily. One study that demonstrated the benefits of magnesium for coronary artery disease involved daily doses of 730 mg.⁶⁴

• Integrative MD
• Naturopathic doctor
• Clinical nutritionist or registered dietitian

Safety Issues

The US government has set the following upper limits for use of magnesium supplements:

• Children

• 1-3 years: 65 mg

• 4-8 years: 110 mg

• Adults: 350 mg

• Pregnant or Nursing Women: 350 mg

In general, magnesium appears to be quite safe when taken at or below recommended dosages. The most common complaint is loose stools. However, people with severe kidney or heart disease should not take magnesium (or any other supplement) except on the advice of a physician. Maximum safe dosages have not been established for young children. There has been one case of death caused by excessive use of magnesium supplements in a developmentally and physically disabled child. ¹ Pregnant or nursing women should not exceed the nutritional dosages presented under Requirements/Sources .

If taken at the same time, magnesium can interfere with the absorption of antibiotics in the tetracycline family, ² and, possibly, the drug nitrofurantoin . ³ Also, when combined with oral diabetes drugs in the sulfonylurea family, magnesium may cause blood sugar levels to fall more than expected. ⁴

Interactions You Should Know About

If you are taking:

• Potassium supplements , manganese , loop and thiazide diuretics , oral contraceptives , estrogen-replacement therapy , cisplatin, digoxin , or medications that reduce stomach acid: You may need extra magnesium.

• Antibiotics in the tetracycline family or nitrofurantoin (Macrodantin): You should separate your magnesium dose from doses of these medications by at least 2 hours to avoid absorption problems.

• Oral diabetes medications in the sulfonylurea family (Tolinase, Micronase, Orinase, Glucotrol, Diabinese, DiaBeta): Work closely with your physician when taking magnesium to avoid hypoglycemia.

• Amiloride : Do not take magnesium supplements except on medical advice. ⁵

1. McGuire JK, Kulkarni MS, Baden HP. Fatal hypermagnesemia in a child treated with megavitamin/megamineral therapy. Pediatrics. 105(2):E18.
2. Tatro D, ed. Drug Interaction Facts. St. Louis, MO: Facts and Comparisons; 1999.
3. Naggar VF, Khalil SA. Effect of magnesium trisilicate on nitrofurantoin absorption. Clin Pharmacol Ther. 25(6):857-63.
4. Drug Evaluations Annual. Vol 2. Milwaukee, WI: American Medical Association; 1994.
5. Rudnicki M, Frölich A, Rasmussen WF, McNair P. The effect of magnesium on maternal blood pressure in pregnancy-induced hypertension. A randomized double-blind placebo-controlled trial. Acta Obstet Gynecol Scand. 70(6):445-50.

48. Cohen L, Kitzes R. Magnesium sulfate and digitalis-toxic arrhythmias. JAMA. 1983;249:2808-2810.
49. Toffaletti J. Electrolytes, divalent cations, and blood gases (magnesium). Anal Chem. 1991;63:192R-194R.
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52. Bashir Y, Sneddon JF, Staunton A, et al. Effects of long-term oral magnesium chloride replacement in congestive heart failure secondary to coronary artery disease. Am J Cardiol. 1993;72:1156-1162.
57. Branea I, Gaita D, Dragulescu I, et al. Assessment of treatment with orotate magnesium in early postoperative period of patients with cardiac insufficiency and coronary artery by-pass grafts (ATOMIC). Rom J Intern Med. 2004;37:287-296.
63. Stepura OB, Martynow AI. Magnesium orotate in severe congestive heart failure (MACH). Int J Cardiol. 2008 Feb 15.
64. Shechter M, Bairey Merz CN, Stuehlinger HG, et al. Effects of oral magnesium therapy on exercise tolerance, exercise-induced chest pain, and quality of life in patients with coronary artery disease. Am J Cardiol. 2003;91:517-521.