If you are currently being treated with any of the following medications, you
should not use magnesium without first talking to your healthcare provider.
The absorption of quinolone antibiotics (such as
ciprofloxacin and moxofloxacin), tetracycline antibiotics (including
tetracycline, doxycycline, and minocycline), and nitrofurantoin is diminished
when taken with magnesium supplements. Therefore, magnesium should be taken two
to four hours before or after taking these medications to avoid interference
Blood Pressure Medications, Calcium Channel Blockers
Magnesium may increase the likelihood of negative side effects
(such as dizziness, nausea, and fluid retention) from calcium channel blockers
(particularly nifedipine) in pregnant women. Other calcium channel blockers
include amlodipine, diltiazem, felodipine, and verapamil.
Magnesium hydroxide, commonly found in
antacids, may increase the absorption of glipizide and glyburide, medications
used to control blood sugar levels. Ultimately, this may prove to allow for
reduction in the dosage of those medications.
It is important that normal levels of magnesium be
maintained while taking digoxin because low blood levels of magnesium can
increase adverse effects from this drug. In addition, digoxin can lead to
increased loss of magnesium in the urine. A healthcare provider will follow
magnesium levels closely to determine whether magnesium supplementation is
Two types of diuretics known as loop (such as
furosemide) and thiazide (including hydrochlorothiazide) can deplete magnesium
levels. For this reason, physicians who prescribe diuretics may consider
recommending magnesium supplements as well.
Hormone Replacement Therapy for menopause
tend to decrease during menopause. Studies suggest, however, that hormone
replacement therapy may help prevent the loss of this mineral. Postmenopausal
women or those taking hormone replacement therapy should talk with a healthcare
provider about the risks and benefits of magnesium supplementation.
There have been case reports of magnesium
containing antacids reducing the effectiveness of levothyroxine, which is taken
for an under active thyroid. This is important because many people take
laxatives containing magnesium without letting their doctor know.
Penicillamine, a medication used for the
treatment of Wilson's disease (a condition characterized by high levels of
copper in the body) and rheumatoid arthritis, can inactivate magnesium,
particularly when high doses of the drug are used over a long period of time.
Even with this relative inactivation, however, supplementation with magnesium
and other nutrients by those taking penicillamine may reduce side effects
associated with this medication. A healthcare practitioner can determine whether
magnesium supplements are safe and appropriate if you are taking penicillamine.
Tiludronate and Alendronate
Magnesium may interfere with
absorption of tiludronate, a medication similar to alendronate that is used for
the treatment of osteoporosis. This interaction has not been reported with
alendronate specifically. Magnesium supplements or magnesium-containing antacids
should be taken at least two hours before or two hours after taking these
medications to minimize potential interference with absorption.
Aminoglycoside antibiotics (such as gentamicin and
tobramycin), thiazide diuretics (such as hydrochlorothiazide), loop diuretics
(such as furosemide and bumetanide), amphotericin B, corticosteroids, antacids,
and insulin may lower magnesium levels. Please refer to the depletions
monographs on some of these medications for more information.