Magnesium

Background

• Magnesium is a mineral that is involved in hundreds of reactions in the human body.
• Magnesium sulfate is the main treatment for pregnant women who have seizures or high blood pressure. Strong evidence exists to support these uses of magnesium sulfate. There is also strong evidence to support the use of magnesium in reducing the risk of abnormal heart rhythms. Magnesium supplements may also be used to correct magnesium deficiencies.
• There is good evidence to support the use of magnesium as an additional therapy for treating severe acute childhood asthma, bleeding in the brain, and hearing loss. It has also been used to relieve pain, control blood sugar, and protect against nerve damage in premature infants. More research is needed to support any other clinical use of magnesium.

Scientific Evidence

Uses	Grade*
Abnormal heart rhythms Abnormal heart rhythms are the most common complication after heart surgery. Magnesium injected into the vein may reduce the risk of abnormal heartbeat. However, it may lack effect on length of hospital stay, heart attack risk, and death.	A
High blood pressure associated with pregnancy (and seizures) High blood pressure and seizures are common complications of pregnancy. Magnesium sulfate is often injected into the veins in women who have these conditions. This treatment is considered a superior drug for preventing seizures, as well as reducing death, breathing problems, pneumonia, and coma.	A
Nutrition (magnesium deficiency) Aging may be associated with low levels of magnesium, especially in people who have general nutritional deficiencies. However, low magnesium levels may also be caused by reduced absorption of magnesium, increased loss of magnesium in urine, hormone disorders, insulin resistance, or other diseases or medications. Taking magnesium supplements by mouth has been suggested.	A
Asthma Asthma may frequently worsen and range from mild to severe attacks. The use of magnesium sulfate is one of many treatment options available during acute asthma attacks. Magnesium sulfate injected into the vein or given with other asthma therapies has been shown to be effective for acute asthma attacks, particularly in children with severe symptoms. However, magnesium may lack benefit for mild-to-moderate attacks.	B
Diabetes (type 2) Type 2 diabetes may often be prevented with diet and exercise. Magnesium intake may reduce the risk of developing type 2 diabetes, as well as improve blood sugar control in people who have the condition. Magnesium has been found to have only a small impact on other important factors associated with diabetes complications.	B
Hearing loss The benefits of magnesium taken by mouth have been studied for the treatment of hearing loss caused by noise or an unknown cause. Magnesium treatment has been shown to reduce temporary and permanent hearing loss caused by noise. However, further research is needed in this area.	B
Hemorrhage (bleeding in the brain) Magnesium injected into the vein may help reduce the risk of poor outcome and stroke in people who have bleeding in the brain. Increasing magnesium levels may help improve outcome after bleeding in the brain. Further research is needed to confirm the benefits of magnesium in the treatment of hemorrhage.	B
Nervous system function (premature infants) Premature delivery may cause many nervous system problems in babies. These include blindness, deafness, cerebral palsy (disorder affecting movement and learning), and other disabilities. Studies have looked at the use of magnesium sulfate therapy before birth as a way to protect against nervous system disorders in the baby. This treatment may help improve motor function in early childhood and reduce the risk of cerebral palsy. Some research suggests that there may be an association between magnesium sulfate treatment and a reduced risk of both cerebral palsy and death. Further research is needed to determine optimal dosing.	B
Pain Studies show that magnesium has a small but positive effect as a pain reliever. Magnesium may reduce the need for morphine.	B
Pain relief (during surgery) Magnesium has been found to help spinal anesthesia last longer during surgery. However, more research is needed in this field.	B
Alcohol withdrawal Early research suggests that injecting magnesium into the vein as a supplement to benzodiazepines (anti-anxiety agents) may lack effect on the severity of alcohol withdrawal symptoms. Further research is needed before conclusions can be made.	C
Anxiety Magnesium has been studied for anxiety and related disorders, usually in combination with other vitamins, minerals, or herbal products. One study on magnesium alone found a lack of effect on anxiety. Magnesium combined with vitamin B6 may decrease premenstrual anxiety. Further study is needed.	C
Bipolar disorder Magnesium may help manage manic symptoms when given as supplemental therapy. However, better quality research is needed in this area.	C
Cardiac arrest (loss of heart function) Cardiac arrest is a life-threatening event in which the heart stops contracting properly. Because of an apparent benefit of magnesium for heart attack, it has been used together with other agents for cardiopulmonary resuscitation (CPR). However, it is unclear whether magnesium is the ideal treatment choice for CPR, due to conflicting findings. More research is needed in this area.	C
Chronic fatigue syndrome Evidence suggests that magnesium may benefit people with chronic fatigue syndrome. Further research is needed before conclusions can be made.	C
Chronic lung conditions Chronic obstructive pulmonary disease (COPD) is a lung disease in which the airways become narrowed. It is caused by exposure to fumes such as cigarette smoke, and acute attacks are difficult to treat. Magnesium sulfate injected into the vein and used with lung agents has been found to be safe and modestly effective in the treatment of COPD. More research is needed to make a firm conclusion.	C
Constipation Magnesium hydroxide has been studied for constipation in children, but has been found to be less effective than standard therapy. More research is needed.	C
Fibromyalgia (long-term, body-wide pain) Fibromyalgia is a disorder that causes long-term, widespread pain and sensitivity to gentle touch. It may also cause fatigue, sleep problems, and joint stiffness. Early study reports that Super Malic® (containing malic acid and magnesium) may benefit people with this condition. More research is needed to confirm these findings.	C
Heart attack Magnesium injected into the vein may reduce abnormal heart rhythms, which commonly occur during a heart attack. It is unclear whether magnesium therapy helps reduce the number of deaths caused by heart attacks. Magnesium sulfate injected into the vein has been studied for reducing abnormal heart rhythms and heart failure in people who are unable to receive standard therapy.	C
Heart attack prevention Magnesium has been used in the treatment of heart attack. Magnesium taken by mouth has been studied as a way to prevent recurring heart attacks in people who have survived acute heart attacks. However, results are conflicting and more research is needed.	C
Heart disease Evidence suggests that magnesium may help regulate blood clot formation. Early study reports that taking magnesium by mouth may prevent blood clot formation in people who have coronary artery disease (narrowing of the blood vessels that supply blood to the heart). More research is needed in this area.	C
High blood pressure It is unclear whether magnesium taken by mouth lowers blood pressure in people with mild-to-moderate high blood pressure or prevents the development of high blood pressure. Results are conflicting, with most studies suggesting a small but significant reduction in blood pressure. More research is needed.	C
Kidney diseases Early research suggests that magnesium-based compounds may benefit people undergoing treatment for kidney disease. High levels of magnesium have been linked to improved health status and survival in people with kidney disease. However, further study is needed.	C
Kidney stones There is evidence that kidney stone recurrence may be more common in people who have high levels of magnesium in the urine. Treatment with magnesium hydroxide has been found to prevent new stone formation in people who have calcium stones in the kidneys. However, some results are conflicting and further information is needed.	C
Leg cramps (during pregnancy) Leg cramps are a common problem during pregnancy. Pregnant women often have low levels of magnesium. Raising magnesium levels may decrease leg cramps during pregnancy. Magnesium taken by mouth has been reported to reduce pregnancy-related leg cramps. More research is needed in this area.	C
Menopause Early study has looked at the use of magnesium on bone health in postmenopausal women. However, more research is needed before a firm conclusion can be made.	C
Migraine headache Migraine headaches can be extremely painful and are often accompanied by nausea. More women suffer from migraine headaches than men. Furthermore, migraine headaches in women can be related to the menstrual cycle. Magnesium has been studied for use in migraines. Human studies have found that magnesium sulfate may reduce the intensity of migraine headaches. Low magnesium levels may increase menstrual-related migraines in at-risk women. More research is needed to confirm these results.	C
Mitral valve prolapse Mitral valve prolapse (MVP) is a condition in which a heart valve does not close properly. Low magnesium levels may be a cause of MVP. Many people with MVP have low magnesium levels in the blood. Magnesium supplementation has been reported to improve symptoms of this condition. More research is needed to reach a conclusion.	C
Muscle spasms Magnesium may help prevent involuntary muscle twitching caused by the drug succinylcholine (a muscle relaxant). Muscle twitching is a side effect of general anesthesia given during surgery. More high-quality research is needed to confirm these results.	C
Organophosphate poisoning Organophosphates are a group of chemicals that include insecticides and nerve gases. The use of magnesium in organophosphate poisoning has been studied. Injecting magnesium sulfate into the vein has been found to be effective. More research is needed.	C
Pregnancy-related complications Magnesium sulfate may benefit women with some pregnancy-related complications, but may lack effect on infant death. Further research is needed in this field.	C
Premenstrual syndrome (PMS) PMS symptoms usually appear two weeks before the menstrual cycle begins. They may significantly affect a woman's daily routine during that time. Magnesium taken by mouth may help treat mood changes associated with PMS. More research is needed in this area.	C
Shivering (after surgery) Early research has looked at the use of magnesium for shivering after surgery. Further research is needed to confirm the potential effect of magnesium.	C
Tetanus (bacterial infection of the nervous system) Magnesium has been studied in people who have tetanus, with mixed results. Further study is needed in order to make firm conclusions.	C
Altitude sickness Magnesium citrate has been found to lack effect on symptoms of acute mountain sickness. Further study is needed in this field.	D
Athletic performance Magnesium is involved in many reactions in the body. Low magnesium levels may affect exercise performance. Some experts suspect that magnesium levels may not be adequate in many people, especially athletes. Many female athletes do not get enough magnesium from the diet, and magnesium is also lost in the urine with exercise. To date, there is not enough evidence that taking magnesium can improve athletic performance.	D
Pre-term labor contractions Pre-term labor is considered to be labor that begins before 37 weeks of pregnancy. Magnesium has been used for the prevention of pre-term labor contractions. Available studies have shown a lack of effect of magnesium for this use. Also, it is possible that the use of magnesium for contractions may cause the death of the fetus.	D
Traumatic brain injury There is a lack of evidence at this time to support the use of magnesium salts in people with acute traumatic brain injury. Magnesium has also been studied for other types of brain injury in combination with other agents, with mixed results.	D

*Key to grades:

A: Strong scientific evidence for this use;

B: Good scientific evidence for this use;

C: Unclear scientific evidence for this use;

D: Fair scientific evidence against this use (it may not work);

F: Strong scientific evidence against this use (it likely does not work).

Tradition

• Aging, athletic performance (overtraining syndrome), bowel cleansing, colorectal cancer, growth, H. pylori infection, inflammatory bowel disease, kidney disorders (Gitelman syndrome), multiple sclerosis (pain), nutrition (low potassium levels), osteoporosis, refeeding syndrome prevention (metabolism problems in starved or malnourished people), ringing in the ears, schizophrenia, seizures, spinal cord injury, stroke, thyroid disorders (excess parathyroid hormone), toxicity (cadmium).

Dosing

Adults (18 years and older)

• The daily magnesium requirement for healthy adults has not been clearly established. The recommended dietary allowances for magnesium by mouth are 400 milligrams (for males aged 19-30), 310 milligrams (for females aged 19-30), 420 milligrams (for males aged over 30), and 320 milligrams (for females aged over 30).
• For alcohol withdrawal, 10 millimoles of magnesium has been taken by mouth in the morning, followed by 20 millimoles in the evening for four weeks, starting one week after detoxification.
• For altitude sickness, 400 milligrams of magnesium citrate has been taken by mouth three times daily, starting three days before mountain ascent until the beginning of descent.
• For anxiety, 200 milligrams of magnesium has been taken by mouth daily for up to three months.
• For athletic performance, the following doses have been taken by mouth without evidence of benefit: 17 millimoles of magnesium orotate twice daily for four weeks; 500 milligrams of magnesium oxide daily for three weeks; and 100 milligrams of elemental magnesium daily for one month. Doses of magnesium have ranged from 116-500 milligrams daily, for one day to three months.
• For bipolar disorder, 40 milliequivalents of magnesium has been taken by mouth daily for up to 18 weeks. A dose of 375 milligrams of magnesium oxide has been taken by mouth daily for 16 weeks.
• For hearing loss, 167 milligrams of magnesium aspartate has been taken by mouth daily for eight weeks.
• For high blood pressure, 10-40 millimoles of magnesium has been taken by mouth daily for 3-24 weeks, with no significant benefit observed. Doses of 120-973 milligrams of elemental magnesium have been taken by mouth daily for 3-24 weeks.
• For leg cramps (during pregnancy), five millimoles of elemental magnesium has been taken by mouth daily for three weeks. A dose of 15 millimoles of magnesium has been taken by mouth daily as chewable tablets of magnesium lactate and citrate, one in the morning and two in the evening, for three weeks.
• For migraine headaches, 243-600 milligrams of elemental magnesium has been taken by mouth 1-3 times daily for two months. A dose of 400 milligrams of magnesium oxide, chelated magnesium, or slow-release magnesium has been taken by mouth daily.
• For mitral valve prolapse, 1,200-1,800 milligrams of magnesium carbonate has been taken by mouth daily for five weeks.
• For muscle spasms, 200-366 milligrams of elemental magnesium have been taken by mouth as magnesium salts or combinations of salts as a tablet, slow-release tablet, or powder dissolved in water. A dose of 486 milligrams of elemental magnesium has been injected into the vein over four hours for five days.
• For heart attack prevention, 15 millimoles of magnesium hydroxide has been taken by mouth daily for one year.
• For postmenopausal symptoms, 1,830 milligrams of magnesium has been taken by mouth daily for 30 days.
• For high blood pressure and seizures associated with pregnancy, 80 millimoles of magnesium chloride has been injected into the vein for 24 hours, then 40 millimoles injected into the vein for the next 24 hours, then 5 millimoles of magnesium hydroxide taken by mouth daily until three days after delivery. A common dose of magnesium sulfate injected into the veins is 4 grams, followed by 1-3 grams per hour. Doses have ranged from 5-15 grams of magnesium sulfate injected into the vein or muscle over 5-10 minutes or 2.5-5 grams every 4 hours, sometimes with an infusion of 1 gram afterward and another dose of 2 grams if needed. Other doses injected into the vein or muscle include: a loading dose of 4-14 grams and a maintenance dose of 1-2 grams hourly, 2 milliliters hourly, 2-4 grams over five minutes, 4 grams every hour, and/or 5 grams injected into the muscle every four hours for up to 24 hours.
• For the treatment of premenstrual syndrome (PMS), magnesium pyrrolidone carboxylic acid has been taken by mouth three times daily (for a total daily dose of 360 milligrams of magnesium) from the 15^th day of the menstrual cycle until the beginning of menstruation for two months.
• For pre-term labor contractions, a dose of 200 milligrams of magnesium oxide has been taken by mouth every 3-4 hours or 128 milligrams has been taken by mouth every four hours, along with 535mg Slow-Mag^® (magnesium sulfate) injected into the vein every four hours. The following doses have been used: 6 grams of magnesium sulfate injected into the veins, followed by a dose of 2-4 grams per hour for 24 hours, then 0.5 grams of magnesium sulfate every 4-6 hours; 4 grams of magnesium sulfate injected into the veins, followed by 4-6 grams per hour for six hours, then 2 grams of magnesium gluconate taken by mouth every four hours until delivery or 37 weeks of pregnancy; 6 grams of magnesium sulfate injected into the vein, followed by 2-4 grams per hour for up to 48 hours; 4 grams of magnesium sulfate injected into the vein followed by 2-3 grams per hour of magnesium sulfate; and 4 grams of magnesium sulfate injected into the vein, followed by 2-4 grams per hour until a minimum of 12 hours without contractions within the first two days. Treatment durations ranged from two days to 37 weeks of pregnancy, until delivery, or until 12-24 hours without contractions occurred.
• For skin conditions, magnesium sulfate has been applied to the skin in the form of a gel containing magnesium chloride or a paste. Epsom salts (magnesium sulfate) have been added to bath water.
• For heart attack, 1.92-12 grams of magnesium has been injected into the veins for 20-72 hours.
• For anesthesia, magnesium has been injected into the brain or spinal cord in doses of 25-100 milligrams.
• For pain relief, a single dose of 50-100 milligrams of magnesium sulfate has been injected into the brain or spinal cord. Magnesium sulfate has been injected in doses ranging from 3.7-150 milligrams and as a 24-48 hour epidural infusion (6-500 milligrams hourly). Magnesium has been given with other medications, including fentanyl, sufentanil, morphine, lidocaine, bupivacaine, hyperbaric or isobaric bupivacaine.
• For abnormal heart rhythms, doses have ranged from 1.2-18 grams, 8-329 millimoles, or 40-80 milligrams per kilogram of magnesium sulfate has been injected into the veins over periods ranging from five minutes to 144 hours, sometimes followed by post-surgery infusions lasting up to five days. A dose of 7 millimoles of magnesium sulfate has been injected into the muscle after surgery for 72 hours. Doses of 0.4-25 grams of magnesium have been injected during surgery.
• For asthma, the following doses have been injected into the veins: 10-25 milligrams of magnesium sulfate per kilogram over 20 minutes; 2 grams of magnesium, 30 minutes after emergency department arrival; 2 grams of magnesium sulfate over 20 minutes, followed by 2 grams per hour over four hours plus standard therapy; and 2 grams of magnesium sulfate diluted in 50 milliliters of 5 percent dextrose in water (D5W) 20 minutes, plus a steroid. A nebulizer (a device that delivers medication in the form of mist inhaled into the lungs) has been used to give doses of 1-3 milliliters of isotonic magnesium sulfate, 384-150 milligrams of magnesium, or 3.2 percent magnesium. Up to five nebulized doses of magnesium have been given every 20 minutes or hourly for up to four hours.
• For hemorrhage (bleeding), magnesium has been injected into the vein as 64 millimoles per liter for 14 days. Magnesium has been given as 6 grams or 16-20 millimoles, followed by 2 grams hourly or 64-80 millimoles daily, starting within 48-96 hours of bleeding and lasting 10-14 days.
• For nervous system protection in premature babies, 4-6 grams of magnesium sulfate has been injected into the veins of mothers for 10-30 minutes, followed by 1-3 grams of magnesium sulfate injected hourly for 12 hours after birth, for 24 hours, or until birth.
• For tetanus, 4-5 grams or 40 milligrams per kilogram of magnesium sulfate have been injected into the vein over 20-30 minutes, followed by 2 grams hourly with a reduced dose of 1.5 grams hourly in people weighing less than 45 kilograms.

Children (under 18 years old)

• The recommended dietary allowances for magnesium taken by mouth are 80 milligrams (for ages 1-3), 130 milligrams (for ages 4-8), 240 milligrams (for ages 9-13), 410 milligrams (for males aged 14-18), and 360 milligrams (for females aged 14-18). Adequate intakes for infants are 30 milligrams (for those 0-6 months old) and 75 milligrams (for those 7-12 months old). The safe maximum daily intake for infants has not been determined. The following doses of magnesium have been taken by mouth: 65 milligrams daily for children 1-3 years of age; 110 milligrams daily for children 4-8 years of age; 350 milligrams daily for children aged nine years or older.
• For constipation, magnesium hydroxide (milk of magnesia) doses taken by mouth have ranged from 0.5-3 milliliters per kilogram daily.
• For asthma, the following intravenous doses have been used: 0.2 milliliters of 50 percent magnesium sulfate per kilogram infused into the vein over 35 minutes, in addition to oxygen, nebulized salbutamol, aminophylline (a lung agent); and magnesium sulfate (25 milligrams per kilogram, up to two grams total in 100 milliliters of normal saline solution) plus methylprednisolone infused into the vein (two milligrams per kilogram, up to 100 milligrams total) given prior to receiving magnesium. A nebulizer (a device that delivers medication in the form of mist inhaled into the lungs) has been used to give doses of 1-3 milliliters of isotonic magnesium sulfate, 384-150 milligrams of magnesium, or 3.2 percent magnesium. Up to five nebulized doses of magnesium have been given every 20 minutes or hourly for up to four hours.

References

1. Albrecht E, Kirkham KR, Liu SS, et al. The analgesic efficacy and safety of neuraxial magnesium sulphate: a quantitative review. Anaesthesia 2013;68(2):190-202. View Abstract
2. Arsenault KA, Yusuf AM, Crystal E, et al. Interventions for preventing post-operative atrial fibrillation in patients undergoing heart surgery. Cochrane.Database.Syst.Rev. 2013;1:CD003611. View Abstract
3. Bourne C, Charpiat B, Charhon N, et al. [Emergent adverse effects of proton pump inhibitors]. Presse Med 2013;42(2):e53-e62. View Abstract
4. Cook RC, Yamashita MH, Kearns M, et al. Prophylactic magnesium does not prevent atrial fibrillation after cardiac surgery: a meta-analysis. Ann Thorac.Surg 2013;95(2):533-541. View Abstract
5. Dennis AT. Management of pre-eclampsia: issues for anaesthetists. Anaesthesia 2012;67(9):1009-1020. View Abstract
6. Hruby A, Ngwa JS, Renstrom F, et al. A. Higher magnesium intake is associated with lower fasting glucose and insulin, with no evidence of interaction with select genetic loci, in a meta-analysis of 15 CHARGE Consortium Studies. J Nutr 2013;143(3):345-353. View Abstract
7. Lalloo UG, Ainslie GM, Abdool-Gaffar MS, et al. Guideline for the management of acute asthma in adults: 2013 update. S.Afr.Med J 2013;103(3 Pt 2):189-198. View Abstract
8. Meeusen R, Duclos M, Foster C, et al. Prevention, diagnosis, and treatment of the overtraining syndrome: joint consensus statement of the European College of Sport Science and the American College of Sports Medicine. Med Sci Sports Exerc. 2013;45(1):186-205. View Abstract
9. Morrison AP, Hunter JM, Halpern SH, et al. Effect of intrathecal magnesium in the presence or absence of local anaesthetic with and without lipophilic opioids: a systematic review and meta-analysis. Br J Anaesth. 2013;110(5):702-712. View Abstract
10. Nguyen TM, Crowther CA, Wilkinson D, et al. Magnesium sulphate for women at term for neuroprotection of the fetus. Cochrane.Database.Syst.Rev. 2013;2:CD009395. View Abstract
11. Romero-Arauz JF, Morales-Borrego E, Garcia-Espinosa M, et al. [Clinical guideline. Preeclampsia-eclampsia]. Rev.Med Inst.Mex.Seguro.Soc 2012;50(5):569-579. View Abstract
12. Sylvia LG, Peters AT, Deckersbach T, et al. Nutrient-based therapies for bipolar disorder: a systematic review. Psychother.Psychosom. 2013;82(1):10-19. View Abstract
13. Wen F, Zhou Y, Wang W, et al. Ca/Mg infusions for the prevention of oxaliplatin-related neurotoxicity in patients with colorectal cancer: a meta-analysis. Ann Oncol 2013;24(1):171-178. View Abstract
14. Witteveen JE, van Thiel S, Romijn JA, et al. Hungry bone syndrome: still a challenge in the post-operative management of primary hyperparathyroidism: a systematic review of the literature. Eur J Endocrinol 2013;168(3):R45-R53. View Abstract
15. Wu X, Wang C, Zhu J, et al. Meta-analysis of randomized controlled trials on magnesium in addition to beta-blocker for prevention of postoperative atrial arrhythmias after coronary artery bypass grafting. BMC.Cardiovasc.Disord. 2013;13:5. View Abstract