Also Known As: Paricalcitol, Zemplar
Paricalcitol (marketed by Abbott Laboratories under the trade name Zemplar) is a drug used for the prevention and treatment of secondary hyperparathyroidism (excessive secretion of parathyroid hormone) associated with chronic renal failure. Chemically, it is 19-nor-1,25-(OH)2-vitamin D2 or 19-nor-1,25-dihydroxyvitamin D2, being an analog of 1,25-dihydroxyergocalciferol, the active form of vitamin D2.
In three placebo-controlled studies, chronic renal failure patients treated with paricalcitol achieved a mean parathyroid hormone (PTH) reduction of 30% in six weeks. Additionally there was no difference in incidence of hypercalcemia or hyperphosphatemia when compared to placebo.
A double-blind randomised study with 263 dialysis patients showed a significant advantage over calcitriol (also known as activated vitamin D3; a similar molecule to 1,25-dihydroxyergocalciferol, adding a methyl group on C24 and lacking a double-bond in the C22 position). After 18 weeks, all patients in the paricalcitol group had reached the target parathormone level of 100 to 300 pg/ml, versus none in the calcitriol group.
Forty-eight week therapy with paricalcitol did not alter left ventricular mass index or improve certain measures of diastolic dysfunction in 227 patients with chronic kidney disease.