COMPARISON OF INTERMITTENT ORAL AND INTRAVENOUS CALCITRIOL IN HEMODIALYSIS-PATIENTS WITH SECONDARY HYPERPARATHYROIDISM

Both intermittent intravenous and intermittent oral calcitriol have be en shown to be effective in the treatment of secondary hyperparathyroi dism in hemodialysis patients and it has been claimed that intravenous calcitriol causes less hypercalcemia. However, there has been no publ ished systematic comparison of the two routes of administration of int ermittent calcitriol. Therefore in a prospective crossover study 11 (9 male) patients on maintenance hemodialysis were randomized to receive intravenous followed by oral calcitriol for 4 months each, or oral fo llowed by intravenous calcitriol, commencing at 2 mug postdialysis thr ee times per week. Initial serum immunoreactive parathyroid hormone (P TH) was 446 +/- 111 (normal <65) pg/ml. Calcium-containing phosphate b inders were not used. Calcitriol was ceased if hypercalcemia developed and restarted at 2 mug or 1 mug when calcium returned to normal. Hype rcalcemia was frequent (11 episodes in 8 patients on intravenous calci triol and 10 episodes in 7 patients on oral calcitriol) and dose reduc tion to 1 mug was necessary in 7 patients on intravenous and on 6 pati ents on oral. Serum PTH fell during both treatments. Parathyroid enlar gement was seen in 10 glands from 4 patients, but no size reduction wa s demonstrated with treatment. There was no reduction in activity on q uantitative metabolic bone scan. In summary, intermittent oral calcitr iol and intermittent intravenous calcitriol were equally effective in reducing serum parathyroid hormone levels and at a dose of 2 mug postd ialysis caused hypercalcemia with equal frequency.