High-dose intravenous phosphorus therapy for severe complicated hypophosphatemia

To evaluate the efficacy and safety of a simple approach to intravenous phosphorus therapy, we prospectively studied ten adult patients with severe hypophosphatemia (less than or equal to 1 mg/dl), two or more clinical reasons for the hypophosphatemia, and normal renal function. They were treated with a solution containing 0.32 mmol of phosphorus per kilogram of body weight. This amount of phosphorus was infused intravenously over 12 hours and repeated every 12 hours until the serum phosphorus was greater than or equal to 2 mg/dl. The serum phosphorus, potassium, magnesium, and calcium levels were measured at six hours, 12 hours, and every 12 hours thereafter. The serum phosphorus level was greater than or equal to 2 mg/dl in one patient at six hours, three patients at 12 hours, three patients at 24 hours, four patients at 36 hours, and one patient at 48 hours. The serum calcium was measured every 12 hours and at no time was any patient dangerously hypocalcemic. Administration of 0.32 mmol of phosphorus per kilogram of body weight intravenously over a 12-hour period is both efficacious and safe in severely hypophosphatemic patients with multiple causes of hypophosphatemia, normal renal function, and no hypercalcemia.