EFFECT OF CHOLESTYRAMINE ON MINERAL EXCRETION IN MAN

Cholestyramine in the chloride phase (32 g/day) was given to four hyperlipidaemic patients under balance study conditions. The changes in blood chemistry were slight, but urine pH decreased and the urinary excretion of chloride increased by about 70 mEq/day, corresponding to about 60% of the chloride content of the resin. Urinary excretion of calcium increased significantly (12–60%) in every subject, while faecal excretion did not show a consistent change. Slight equidirectional changes in the excretion of magnesium were observed in every patient, whereas the change in phosphate excretion was negligible. Continued administration of cholestyramine with reduction of the total chloride load to pretreatment values essentially abolished the effect on calcium excretion. Ammonium chloride produced comparable changes in the excretion of calcium. Urinary citrate was followed in one patient and was strongly depressed during the period when chloride excretion was increased. Only transient changes in urinary sodium and potassium were observed. In one patient observed after two months' treatment with cholestyramine the effect on calcium excretion was still apparent. It is concluded that cholestyramine affects mineral balance mainly through its chloride content and it is suggested that care should be taken to decrease the excess chloride load during cholestyramine treatment in order to avoid the development or progression of osteoporosis in patients at risk in this respect.