Successful use of low-dose intravenous paricalcitol in the treatment of severe secondary hyperparathyroidism in a haemodialysis patient

Haemodialysis (HD) patients are commonly affected by secondary hyperparathyroidism (SHPT), hyperphosphataemia and calcitriol deficiency [1]. Classically, serum high PTH levels cause bone-associated diseases, such as osteitis fibrosa and renal osteodystrophy. More recently, the link between SHPT and a systemic toxicity has been elucidated, with SHPT playing a major role in determining cardiovascular disease, including vascular calcification [2,3]. Treatment with calcitriol, the active form of vitamin D, reduces serum PTH levels, but may result in elevations in serum calcium (Ca), phosphorus (P) and Ca × P product levels, increasing the risk of cardiovascular calcification in the HD population [4]. Several new vitamin D analogues have been developed and investigated with the rationale to treat SHPT with a reduced risk of hypercalcaemia and hyperphosphataemia in HD patients [5,6]. Paricalcitol (1,25dihydroxy-19-nor-vitamin D2, 19-Nor-D2) is a vitamin D receptor activator that suppresses PTH secretion with minimal increases in serum calcium and phosphate levels [7,8]. Furthermore, it has recently been demonstrated that paricalcitol prevents vascular calcification in experimental models of renal failure, compared to calcitriol [9,10]. The purpose of the present case report is to analyse the possibility of using low-dose intravenous (i.v.) paricalcitol in the treatment of severe SHPT in HD patients with elevated serum Ca and P levels.