Uses of this Supplement
Chronic Obstructive Pulmonary Disease
Diabetes Mellitus
Headache, Migraine
Myocardial Infarction
Premenstrual Syndrome (PMS)
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Calcium Channel Blockers
Estradiol-containing Medications
Insulin Preparations
Quinolone Antibiotics
Tetracycline Derivatives
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Look Up > Supplements > Magnesium > Interactions
Interactions with Magnesium
Alendronate; Tiludronate

Magnesium salts or magnesium-containing antacids interfere with absorption of tiludronate, a bisphosphonate drug similar to alendronate (PDR 1998). This interaction has not been reported with alendronate. However, calcium and other minerals should be taken at least two hours before or after alendronate administration to minimize interference with the absorption of the drug.

Calcium Channel Blockers

Magnesium sulfate may interact with calcium channel blockers and decrease cardiac function, particularly in pregnant women (Davis et al. 1997). However, another report indicates that using magnesium-enriched salt as a substitute for sodium enhances the cardiovascular effects derived from the combination of low dose felodipine and ramipril in rats (Mervaala et al. 1998).


Hypomagnesemia increases the risk of cardiac glycoside toxicity (Whang et al. 1985). Digoxin decreases the reabsorption of magnesium from the kidneys, which leads to increased excretion in the urine (Crippa et al. 1999). However, adequate amounts of magnesium enhance the antiarrhythmic activity of this drug, particularly by diminishing the ventricular response during atrial fibrillation. One case report describes a patient with digoxin toxicity associated with ventricular tachycardia (Kinlay and Buckley 1995). Treatment with magnesium sulfate (two doses of 10 mmol IV) resulted in a more stable junctional rhythm. Normal magnesium levels should be maintained during digoxin treatment.

Estrogens; Progestins

In a controlled clinical study with 25 healthy women at or past menopause and 15 healthy women of child-bearing age, serum levels of magnesium were inversely related to the serum level of estrogen in both groups (Muneyyirci-Delale et al. 1999). Another group of postmenopausal women treated with conjugated estrogens and medroxyprogesterone for one year had reduced urinary excretion of zinc and magnesium (Herzberg et al. 1996). The clinical significance of this interaction is unknown.

Glipizide; Glyburide

Concomitant ingestion of magnesium hydroxide with both glipizide and glyburide has been shown to increase the rate and extent of absorption of these medications (Kivisto and Neuvonen 1991; Lehto et al. 1996; Neuvonen and Kivisto 1994). The faster rate of absorption may result in increased early insulin and glucose responses (Kivisto and Neuvonen 1991). This effect was observed with magnesium hydroxide antacids, not dietary supplements.

Insulin Preparations

Supplementation with magnesium in patients with type II diabetes mellitus enhances insulin sensitivity and secretion (De Valk 1999). In rats predisposed to type II diabetes, supplementation with oral magnesium diminished the progression of the disease.


Magnesium salts decrease the rate and extent of absorption of nitrofurantoin (Naggar and Khalil 1979). It is not known if dietary supplements containing magnesium will have a similar effect on nitrofurantoin absorption.


Penicillamine can inactivate magnesium, particularly when high doses are used over a long period of time (Seelig 1982). However, supplementation with magnesium and other nutrients in over 50 patients on penicillamine therapy for the treatment of autoimmune disorders resulted in fewer adverse reactions than those commonly experienced in patients treated with the drug alone.

Quinolone Antibiotics

Quinolone antibiotics form chelates with metal cations, such as aluminum, magnesium, calcium, iron, zinc, copper, and manganese (Kara et al. 1991; Li et al. 1999), which significantly reduces the absorption of these medications (Balfour and Wiseman 1999; Brouwers 1992; Campbell and Hasinoff 1991). Dietary supplements and antacids containing aluminum and magnesium should be taken two to four hours before or after administration of these antibiotics (Hines Burnham et al. 2000).

Tetracycline Derivatives

Tetracyclines form chelates with divalent and trivalent cations, including iron, aluminum, magnesium, and calcium (Neuvonen 1976). It has been reported that these chelates are poorly soluble and can significantly reduce the absorption and efficacy of tetracyclines (Hines Burnham et al. 2000; Neuvonen 1976). However, one study reports that magnesium-tetracycline complexes may be more bioavailable than uncomplexed tetracycline due to a higher degree of membrane diffusion (Lambs et al. 1984).


Balfour JA, Wiseman LR. Moxifloxacin. Drugs. 1999;57(3):363-374.

Brouwers JR. Drug interactions with quinolone antibacterials. Drug Saf. 1992;7:268-281.

Campbell NR, Hasinoff BB. Iron supplements: a common cause of drug interactions. Br J Clin Pharmacol. 1991;31(3):251-255.

Crippa G, Sverzellati E, Girogi Pierfranceschi M, et al. Magnesium and cardiovascular drugs: interactions and therapeutic role. Ann Ital Med Int. 1999:14(1):40-45.

Davis WB, Wells SR, Kuller JA, et al. Analysis of the risks associated with calcium channel blockade: implications for the obstetrician-gynecologist. Obstet Gynecol Surv. 1997;52(3):198-201.

De Valk HW. Magnesium in diabetes mellitus. Neth J Med. 1999: 54(4):139-146.

Herzberg M, Lusky A, Blonder J, Frenkel Y. The effect of estrogen replacement therapy on zinc in serum and urine. Obstet Gynecol. 1996;87(6):1035-1040.

Hines Burnham T, et al, eds. Drug Facts and Comparisons. St. Louis, MO:Facts and Comparisons;2000:1286.

Kara M, Hasinoff BB, McKay DW, et al. Clinical and chemical interactions between iron preparations and ciprofloxacin. Br J Clin Pharmacol. 1991;31(3):257-261.

Kinlay S, Buckley NA. Magnesium sulfate in the treatment of ventricular arrhythmias due to digoxin toxicity. J Toxicol Clin Toxicol. 1995;33:55-59.

Kivisto KT, Neuvonen PJ. Enhancement of absorption and effect of glipizide by magnesium hydroxide. Clin Pharmacol Ther. 1991;49(1):39-43.

Lambs L, Brion M, Berthon G. Metal ion-tetracycline interactions in biological fluids. Part 3. Formation of mixed-metal ternary complexes of tetracycline, oxytetracycline, doxycycline and minocycline with calcium and magnesium, and their involvement in the bioavailability of these antibiotics in blood plasma. Agents Actions. 1984;14:743-750.

Lehto P, Laine K, Kivisto KT, et al. The effect of pH on the in-vitro dissolution of three second-generation sulphoylurea preparations: mechanism of antacid-sulphonylurea interaction. J Pharm Pharmacol. 1996;48(9):899-901.

Li RC, Lo KN, Lam JS, et al. Effects of order of magnesium exposure on the postantibiotic effect and bactericidal activity of ciprofloxacin. J Chemother. 1999;11(4):24324-7.

Mervaala EM, Malmberg L, Teravainen TL, Laakso J, Vapaatalo H, Karppanen H. Influence of dietary salts on the cardiovascular effects of low-dose combination of ramipril and felodipine in spontaneously hypertensive rats. Br J Pharmacol. 1998;123(2):195-204.

Muneyyirci-Delale O, Nacharaju VL, Dalloul M, Altura BM, Altura BT. Serum ionized magnesium and calcium in women after menopause: Inverse relation of estrogen with ionized magnesium. Fertil Steril. 1999;71:869-872.

Naggar VF, Khalil SA. Effect of magnesium trisilicate on nitrofurantoin absorption. Clin Pharmacol Ther. 1979;25(6):857-863.

Neuvonen PJ. Interactions with the absorption of tetracyclines. Drugs. 1976;11(1):45-54.

Neuvonen PJ, Kivisto KT. Enhancement of drug absorption by antacids. An unrecognized drug interaction. Clin Pharmacokinet. 1994;27(2):120-128.

Physicians' Desk Reference, PDR. 52nd ed. Montvale, NJ: Medical Economics Company; 1998.

Seelig MS. Auto-immune complications of D-penicillamine - a possible result of zinc and magnesium depletion and of pyridoxine inactivation. J Am Coll Nutr. 1982: 1(2):207-214.

Whang R, Oei TO, Watanabe A. Frequency of hypomagnesia in hospitalized patients receiving digitalis. Arch Intern Med. 1985;145(4):655-656.

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