Magnesium, in general, is an abundant and fundamental nutrient that each and every human on this planet requires in order to function. Every now and then, however, there is a contraindication to magnesium use. Not surprisingly, most of the contraindications have very little to do with magnesium itself, and a lot to do with pharmaceutical components.
As with any contraindication, you should consult with your physician prior to incorporating a magnesium supplement into your diet if you feel there may be risk of negative interaction. When in doubt, always err on the side of caution.
Magnesium supplementation may not be recommended for those taking blood pressure medications / calcium channel blockers* for a number of reasons.
Through numerous research studies, magnesium has been shown to have a natural ability to lower blood pressure1 – ergo, combining it with a drug that artificially lowers blood pressure and you may find yourself with? You guessed it! Dangerously low blood pressure.
Magnesium and calcium are complimentary to each other – magnesium often acting as a sort of barrier or guardian to keep calcium in line and out of places it shouldn’t be. It will naturally disrupt the movement of calcium through calcium channels and, because of this, it may increase the effect of synthetic calcium channel blockers, leading to dangerous results.
*Nifedipine – a calcium channel blocker – has become a drug that’s commonly used in premature labor. There are specific contraindications to use of magnesium sulfate with this drug.
If you have been diagnosed with kidney failure or suspect that your kidneys are not functioning properly, magnesium intake will need to be strictly monitored or discontinued.
For those that are already on dialysis, this may not be as much of an issue given the fact that dialysis is able to remove excess amounts of minerals that have built up in the body. For some, use of magnesium may alleviate the muscle cramps that often go hand-in-hand with kidney failure and dialysis treatments.
Diabetes & Insulin
If you’ve read our article on magnesium & diabetes, you’ll know that magnesium is very beneficial – nay, essential! – to those struggling with this debilitating disease, specifically Type II2 . But (and there’s always a but, isn’t there?), because of the fact that magnesium plays such a key metabolic role in the body, it can cause issues with those that routinely utilize insulin injections.
Use of magnesium may reduce the amount of injected insulin that is required by helping boost pancreatic insulin production, while also increasing insulin sensitivity in cells.This possibility is significant enough to warrant extra attention and caution – hence being listed amongst our “contraindications”.
Quinolone antibiotics (such as ciprofloxacin & moxifloxacin), tetracycline antibiotics (such as minocycline & doxycycline), and nitrofurantoin are all on the list of antibiotics whose absorption is hindered by the intake of magnesium. Although this is usually something that is explained both by your pharmacist as well as printed on the prescription label, magnesium supplementation needs to be scheduled with a 2 hour gap away from your antibiotic dose.
However, this is something that only applies to oral magnesium supplements since it refers to the binding effect that one may have on the other in the gut creating non-absorbable complexes.
The majority of these are all hindered via the same gut-binding issue that the above listed antibiotics are, so these contraindications are also only pertaining to oral supplementation of magnesium, unless stated otherwise.
- Levothyroxine: taken for an under-active thyroid.
- Tiludronate & Alendronate: used in the treatment of osteoporosis – which is hilarious in and of itself, since magnesium has been repeatedly found to help with bone density and osteoporosis.3
- Warfarin (Coumadin): this medication is a popular blood thinner.
Myasthenia Gravis is a type of auto-immune disorder that may not benefit, or be adversely affected by magnesium supplementation due to it’s role in nerve and muscle function (and neuromuscular transmission).
Other potential contraindications for magnesium include those with excessively slow heart rate, since magnesium is a natural muscle relaxer and may slow heart rate further; also, those with intestinal blockage should not consume oral magnesium supplements/laxatives.
If you have any to add that have been missed, please don’t hesitate to mention it to us.
- L Kass, J Weekes, L Carpenter (2012). European Journal of Clinical Nutrition. Effect of magnesium supplementation on blood pressure: a meta-analysis , Vol. 66, pp. 411-418; DOI: 10.1038/ejcn.2012.4 [↵]
- Rodriguez-Moran M. & Guerrero-Romero M (2003). Diabetes Care. Oral Magnesium Supplementation Improves Insulin Sensitivity and Metabolic Control in Type 2 Diabetic Subjects, Vol. 26 no. 4 1147-1152. DOI: 10.2337/diacare.26.4.1147 [↵]
- Sojka J.E. (1995) Nutrition Reviews. Magnesium Supplementation and Osteoporosis, Vol. 53, Issue 3, pp 71-74 [↵]