A Practical Approach to Administration of Intravenous Calcitriol in an Outpatient Dialysis Setting

Abstract

The purpose of this study was to determine whether a protocol implemented and monitored by renal dietitians (RDs) for intravenous vitamin D₃ metabolite calcitriol (Calcijex, Abbott Laboratories, North Chicago, IL) would be effective in a clinical outpatient setting in achieving parathryoid suppression. A contingency and treatment protocol was established by RDs and nephrologists. At the end of the 6-month period, 47 patients were on the protocol at least 90 days. Blood values were done bimonthly for calcium, phosphorus, alkaline phosphatase, and parathyroid hormone (PTH). All patients were instructed by RDs on phosphorus restriction. Calcitriol therapy was started on acceptable serum levels of calcium less than 10.5 mg/dL (2.62 mmol/L) and phosphorous less than 6.5 mg/dL (2.10 mmol/L); calcitriol was withheld when the calcium times phosphorous product was greater than 73. Patients were referred to a nephrologist on persistent calcium and phosphorous imbalance for evaluation of hyperparathyroidism and/or aluminum toxicity. Calcitriol was withheld 26% of the time: 22% due to high calcium and 78% due to high phosphorous or high calcium times phosphorous product. Calcium level was significantly higher at the end of the study (<i>P</i> < .01). Twenty-two patients (47%) had an average 53% decrease in PTH level. The protocol was applicable to the outpatient dialysis clinic setting and easily monitored by RDs with extra hours approved. The protocol achieved the goals of improved calcium and phosphorous control while suppressing PTH values in a large number of patients, with no morbidity detected. Additional RD hours were required to provide adequate time for ongoing follow-up and patient education. Further study is necessary to determine factors that contributed to lack of response.