Indications for Magnesium Oxide and Follow-up

As seen in the Consultant Connection November 2013 Issue
Kimberly Baucher Ohio Northern University, PharmD Candidate

Many elderly patients are being discharged from the hospital on magnesium oxide without a clear indication. These patients also lack a recommendation for follow-up and monitoring while on this medication. Before determining follow-up it is important to find out what magnesium oxide is being used for. Magnesium oxide is specifically indicated for use as a dietary supplement, relief of indigestion and short-term for treatment of occasional constipation. However, since low magnesium levels can cause complications, supplementation can have benefits aside from just achieving normal magnesium levels.
Studies have been performed using magnesium in diabetic patients and the resulting effect on the lipid profile and glycemic control. However, while there are proven benefits in the lipid profile and glycemic control, diabetic patients tend to have lower magnesium levels to begin with. No studies have looked to see if these benefits would also exist for patients who are not diabetic but have low magnesium levels. Low magnesium levels have also been studied to have a role in depression, osteoporosis and restless leg syndrome. Eating a healthy diet which includes eating foods high in magnesium is associated with lower blood pressure but studies have not shown magnesium supplementation to have the same benefit. Magnesium supplementation has also been studied in patients with heart failure as they are more at risk for developing arrhythmias. It has shown to be beneficial in a study which followed patients taking a magnesium supplement for a year; however, it is important to ensure magnesium levels do not go too high as this may also cause cardiovascular complications.
There is no clear reason why patients are discharged from the hospital on magnesium oxide. However, if a patient has low magnesium it would be beneficial to use a supplement for many reasons as outlined above. The daily recommended intake of magnesium is 310 mg for females and 420 mg for males. When a supplement is being utilized the recommended dose is 800 mg a day. While the most frequently defined side effect is diarrhea, it is rare except with very high does, and it should be monitored. It is important to monitor magnesium levels while on supplements, though there is no defined time period between watching levels. the first time a magnesium level should be monitored is no more than 8 weeks after initiation of the supplement. After the initial level, levels should continue to be monitored at least twice a year. If levels come back high or the patient shows signs of high magnesium, the supplement should be stopped immediately. There is no defined time that a patient should remain on magnesium. As long as the patient’s levels remain within normal range and there is a clear indication for use, the patient may remain on the supplement.

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