Comparison of the effects of magnesium hydroxide and a bulk laxative on lipids, carbohydrates, vitamins A and E, and minerals in geriatric hospital patients in the treatment of constipation.

In a crossover study the effects of magnesium hydroxide on serum lipids, carbohydrates, vitamins A and E, uric acid and whole blood minerals were compared with those of a bulk laxative containing plantago rind and sorbitol in 64 constipated, elderly long-stay patients, 55 of whom were receiving diuretics. Hypomagnesaemia occurred in 11 (17%) patients after bulk laxative and in two (2%) patients after magnesium hydroxide treatment. There was a slight reduction in low values of high-density lipoprotein cholesterol and high values of triglycerides after magnesium hydroxide treatment. There were no significant differences in plasma lipids, whole blood minerals or vitamins A and E using either laxative. Negative correlations were found between the increase in serum concentrations of magnesium and glycosylated haemoglobin A1 (P less than 0.02) and the serum level of uric acid (P less than 0.01). These results suggest that the long-term effects of magnesium hydroxide and bulk laxative on the absorption of nutrients may not be significantly different. Magnesium hydroxide, however, may have beneficial effects on lipid disorders, impaired glucose tolerance and hyperuricaemia in magnesium deficiency due to diuretics and thus may be a favourable laxative for use in bedridden geriatric patients receiving diuretics.