Magnesium is used often used as a medication. It is used as an antacid and to treat ailments such as constipation, magnesium deficiency, some irregular heart rhythms, and high blood pressure and protein in the urine during pregnancy. Sometimes too much magnesium causes magnesium toxicity, a potentially dangerous condition. Calcium gluconate is one way to treat magnesium toxicity. It is generally administered in a hospital and will be carefully overseen by your personal health care professional.
Magnesium and calcium are both important minerals in the body. According to Harrison's Principles of Internal Medicine by Anthony S. Fauci M.D., they both play important roles in normal cell communication, nerve and muscle functions and health of the immune system, and they both augment hundreds of chemical reactions in the body. They are found in high levels in the bones, where they impart strength and structure.
Like many vitamins and minerals, excessive amounts of magnesium can be toxic. As noted by the National Institutes of Health, foods generally do not have enough magnesium to be toxic, but taking magnesium supplements can lead to overdose. Symptoms include mental status changes such as disorientation, confusion and changes in the level of consciousness. The muscles may become weak, and tendon reflexes can decrease. Gastrointestinal problems include nausea, vomiting, diarrhea or loss of appetite. Some people may experience shortness of breath, heart problems and low blood pressure. Two of the most acutely dangerous aspects of magnesium toxicity are its effects on the heart and brain, which can lead to dangerous and even deadly complications.
Calcium gluconate is a useful treatment for magnesium toxicity several reasons. First, high magnesium can cause calcium levels to drop in the body, which causes further problems with cellular functioning and requires replenishment of the calcium. Second, calcium treats the harmful effects magnesium has on the heart, nerves and muscles.
The dosing of calcium gluconate for magnesium toxicity depends on whether it is given to children or adults. Adults are usually given 100 to 300 mg of calcium gluconate, diluted in water with sugar dextrose, delivered by IV over a 10 minute period. Children are given calcium gluconate based on body weight. It is not given in pill form because the IV allows higher doses to enter the circulation much faster.
Your doctor will watch you closely when treating you with calcium gluconate. It can interfere with electrical functioning of the heart by causing heart blocks, which is when the electrical activity traveling from the top of the heart to the bottom is abnormally delayed. It is used with caution when treating pregnant women because it has shown to have some risks in animals -- to date, human studies have not shown a risk. Patients using the medicine digoxin need to be treated with care because excess calcium with this medication makes the heart contract too forcefully. Administration of calcium can also make acid levels in the blood rise. Caution should also be used in those with high phosphate levels because calcium and phosphate bind together to form a solid compound in the blood vessels.
- "Harrison's Principles of Internal Medicine"; Anthony S Fauci et al; 17th Ed 2008
- NIH Office of Dietary Supplements: Magnesium: What Is the Health Risk of Too Much Magnesium?