Question

Since the ban on specific laxative ingredients a few years back, I have resorted to taking magnesium to promote regularity. I have gone from taking 1,500 mg per day to 6,000 mg per day. Could this be having an effect on my heart?

Answer

Constipation can be a difficult problem to treat. Patients often use many types of over-the-counter laxatives and stool softeners before finding one that suits them consistently. Many of these laxatives use ingredients such as magnesium to achieve the desired effect.

While small doses of magnesium-containing laxatives are safe, larger doses may not be. This is especially true for long-term use. If you are taking 6,000 mg daily of Milk of Magnesia, this is indeed a large dose. Side-effects may relate to two types of problems that might develop.

First, there is the potential for absorption of large quantities of magnesium from the gut. This can lead to neurologic problems (depressed reflexes, drowsiness, visual changes, and weakness), and potentially cardiac problems. Magnesium is involved with regulating the metabolism of both calcium and potassium, and thus there may be derangements in these as well. Also, as a result of large doses of magnesium and treatment of constipation, you might be losing certain electrolytes in the stool that may also affect the heart function.

The kidneys help in regulating the amounts of electrolytes in the blood, as well as magnesium and calcium. If you have a degree of kidney dysfunction, this can magnify the previously mentioned side-effects of magnesium therapy.

I suggest an evaluation by a gastroenterologist, in order to develop a better regimen for treating your constipation. What may be needed is fiber supplementation and/or other types of softeners and laxatives.

Links

• Managing Constipation and Diverticular Disease