Print Send a link

Magnesium Teaching Materials

Magnesium Handout

There are studies showing iv magnesium to be helpful with preeclampsia(A), torsades de pointes and other arrhythmias including afib and VTach(B), acute asthma(B), cluster headaches, and so on, but I will focus on oral magnesium. There have been fewer studies of this form, thus the lower evidence ratings, but all are proven by clinical trials (except Mg deficiency and constipation, where you do not need a study) and my clinical impression is of remarkable efficacy.

Food sources: fish, nuts, spinach, beans, etc.

Indications for oral magnesium:
1. Magnesium deficiency – occurs commonly in alcoholism, diuretic therapy, chronic diarrhea, diabetes (25% to 38% of people with T2DM); underdiagnosed, because hypomagnesemia is end-stage(i.e. body stores can be depleted with normal serum levels)
Consequences: Can cause hypokalemia, negatively affect insulin sensitivity/diabetic control, cause arrhythmia, weakness, and affect bone density.
2. Constipation (B) – in addition to prn use as a strong laxative, this can be very effective as a daily/ongoing therapy (Titrate to effect)
3. Kidney Stones(C) – decrease risk of recurrence (I recommend MgCitrate for this, since citrate also can help prevent recurrence.)
4. Fibromyalgia (B) – magnesium malate is the studied form
5. Migraine (B) – Decrease frequency and severity of migraines, especially hormone-related. Also useful in acute treatment, as an iv bolus of 1-2 grams.
6. Osteoporosis – magnesium deficiency increases risk of osteoporosis; interventional trials not yet done.
7. Leg cramps in pregnancy (B)
8. Hearing Loss Protection (B) – protective for noise-induced hearing loss and also helpful in acute hearing loss

Forms of magnesium:
Magnesium chloride 64 mg - causes less diarrhea, is better absorbed – use for everything but constipation, and actually helps that as well.
Magnesium oxide – causes diarrhea, minimal absorption
Magnesium malate – well-absorbed, helpful in fibromyalgia
Magnesium citrate – familiar OTC laxative. Can be taken in small, measured amounts as a magnesium supplement. 876 mg/Tblsp, so usual dose is 1-2 tsp.

Dose: 300 - 600 mg daily is a commonly studied dose. (Connie’s pearl: in people with normal kidney function, I have them titrate to bowel tolerance but not exceed about 1200 mg/d; once we are seeing benefit, I will commonly back down to a more moderate dose.)
Side effects: gi discomfort or diarrhea
Cautions: Can accumulate in renal failure; do not use in people with heart block

Medication Interactions:
Inhibits absorption of many medications, esp. thyroid, quinolones or tetracyclines
Take it at separate time.
(I generally give at hs – it helps with sleep, and it is easier to avoid other meds at that time)

Pearls for use: I use it orally for some of the iv indications, like for palpitations, and I also have seen it be helpful for sleep and anxiety.

Common instructions for use:
Use magnesium malate or citrate or any other form of magnesium but not magnesium oxide. Start with 1-2 capsules per day or with 1 tsp per day of liquid magnesium citrate and gradually increase the dose to the maximum dose tolerated without diarrhea or until symptoms are relieved.
Generally do not exceed 320 mg per day of "elemental magnesium." Do not use this if there are problems with your kidney function.

Epsom salts can also be used but be careful - a full daily dose by mouth would be 1/4 tsp (283 mg elemental magnesium) or just a little more
There is also some absorption through the skin when used in a bath, but a wider margin for safety with this technique. Generally, 1-2 cups of Epsom salts per bathtub is recommended.