Learn about the relation between magnesium and migraine through this article.
Does taking magnesium reduce migraine?
The ideal medication for prevention and treatment of migraine would have no side effects, no risk, would be safe in pregnancy, as well as be highly effective while remaining inexpensive. Of course, no such medication exists, but magnesium is better than many substances used in treating migraine, from this point of view.
What form of magnesium is best for treating migraine?
Magnesium oxide is frequently used in pill form to prevent migraine, usually at a dose of 400-600 mg per day. Acutely, magnesium oxide can be dosed in pill form at the same dosage or given intravenously as magnesium sulfate at 1-2 gm. The most frequent side effect is diarrhea, which can be helpful in those prone to constipation. Diarrhea and abdominal cramping that is sometimes experienced is dose-responsive, such that a lower dose or decreasing the frequency of intake usually takes care of the problem.
Magnesium oxide in doses up to 400 mg is pregnancy category A, which means it can be used safely in pregnancy. Magnesium sulfate, typically given intravenously, now carries a warning related to bone thinning seen in the developing fetus when used longer than 5-7 days in a row. This side effect was discovered in the context of high doses being given to pregnant women to prevent preterm labor.
The most substantial evidence for magnesium’s effectiveness is in patients who have or have had aura with their migraine. It is believed magnesium may prevent the wave of brain signaling, called cortical spreading depression, which produces the visual and sensory changes in the common forms of aura. Other mechanisms of magnesium action include improved platelet function and decreased release or blocking of pain transmitting chemicals in the brain, such as Substance P and glutamate. Magnesium may also prevent the narrowing of brain blood vessels caused by the neurotransmitter serotonin.
Daily oral magnesium has also been shown to prevent menstruation-related migraine, especially in those with pre-menstrual migraine. This means that preventive use can target those with aura or those with menstruation-related migraine, even for those with irregular menstrual cycles.
It is challenging to measure magnesium levels accurately, because levels in the bloodstream may represent only 2% of total body stores, with the rest of magnesium stored in the bones or within cells. Most importantly, simple magnesium blood levels do not accurately measure magnesium levels in the brain. This has led to uncertainty concerning whether correcting a low magnesium level is necessary in treatment or whether magnesium effectiveness is related to low blood levels in the first place. Measurement of ionized magnesium or red blood cell magnesium levels is thought to be more accurate, but these laboratory tests are more difficult and expensive to obtain.
Can low magnesium cause migraine?
Because magnesium may not be accurately measured, low magnesium in the brain can be difficult to prove. Those prone to low magnesium include people with heart disease, diabetes, alcoholism, and those on diuretics for blood pressure. There is some evidence that people with migraine may have lower brain magnesium levels either from decreased absorption of magnesium in food, a genetic tendency to low brain magnesium, or from excreting magnesium from the body. Studies of people with migraine have found low levels of brain magnesium and spinal fluid magnesium in between migraine attacks.
In 2012, the American Headache Society and the American Academy of Neurology reviewed the studies on medications used for migraine prevention and gave magnesium a Level B rating; that is, it is probably effective and should be considered for patients requiring migraine preventive therapy. Because of its safety profile and the lack of serious side effects, magnesium is often chosen as a preventive strategy either alone or with other preventive medications.
Magnesium has also been studied for the acute treatment of severe, difficult-to-treat migraine. Magnesium sulfate given intravenously was most effective in those with a history of migraine with aura. In those without a history of aura, no difference was seen in immediate pain relief or nausea relief by magnesium. Still, there was less light and noise sensitivity after the infusion.
Magnesium oxide, in tablet form, is inexpensive, does not require a prescription, and may be considered reasonable prevention in those who have a history of aura, menstruation-related migraine, no health insurance, or who may become pregnant. Because of the excellent safety profile of magnesium, any patient who has frequent migraine and is considering a preventive strategy to reduce the frequency or severity of their headaches may want to consider this option and discuss it with their doctor.