Overdose of<unk> (hypermagnesemia) is only possible in special circumstances. It can cause diarrhea, nausea, vomiting, severely lowered blood pressure, confusion, slowed heart rate, respiratory paralysis. In very severe cases, it can cause coma, cardiac arrhythmia, cardiac arrest and death.<unk> overdose can be counteracted by administering calcium gluconate.
Magnesium 
Calcium
Potassium
Calamine
Milium 
Calcium carbonate
Copper 
Folate