Q. People’s Pharmacy has gotten me into a problem with my dear wife. As a regular reader of your column, I always share stuff with her if I think it may help. Your comment about taking magnesium supplements to help alleviate persistent constipation is a case in point.
She started taking magnesium and it helped her bowel function immediately. I was happy to have her benefit from your column. So what’s the problem?
Her 90-year-old father, a long-time heavy user of milk of magnesia, is now having significant kidney malfunction issues. His medical advisors have identified the laxative as the cause.
My wife has abruptly stopped using her magnesium supplement because of what is occurring with her dad. Could you kindly comment on any kidney risks associated with magnesium?
A. Magnesium is essential for muscles, nerves and bones. This mineral helps regulate blood sugar, blood pressure and heart rhythm.
The daily RDA is 420 mg for men and 320 mg for women. American diets are frequently low in magnesium, and commonly prescribed blood pressure medicines containing diuretics may deplete this mineral.
People with kidney problems are unable to tolerate excess magnesium. They should avoid supplements, laxatives or antacids that contain this mineral. Overdosing on magnesium may overwhelm the system and result in magnesium toxicity. This may be what happened to your father-in-law because of his milk of magnesia habit.
If your wife’s kidney function is normal and her physician monitors her magnesium levels she should be able to tolerate up to 350 mg daily.