Elevated serum parathyroid hormone concentration during treatment with high ceiling diuretics.

Serum concentrations of parathyroid hormone (s-PTH) calcium, phosphorus and alkaline phosphatase were measured during treatment with furosemide or bumetanide for congestive heart failure. Significant elevations both of s-PTH and alkaline phosphatase were found, whereas serum calcium concentration was decreased. The changes were not related to the dose of drug or to the duration of treatment. It is concluded that treatment with furosemide or bumetanide may cause hypocalcaemia, resulting in elevation of s-PTH. The increased concentration of alkaline phosphatase may indicate accelerated bone remodelling, as found in primary hyperparathyroidism.