The Beneficial Effect of Paricalcitol (Zemplar) on Secondary hyperparathyroidism Refractory to Calcitriol (Calcijex) and Cinacalcet HCl (Mimpara) in Patients on Maintenance Hemodialysis: A Prospective and Crossover Study

Paricalcitol, 19-nor-1, 25-dihydroxvitamin D2, is a novel 1,25–dihydroxyvitamin D2 analogue, which has greater potential to suppress parathyroid hormone without inducing significant hypercalcemia and hyperphosphatemia. We therefore investigated its role in treatment of patients with moderate to severe secondary hyperparathyroidism (SHPT) who were refractory to conventional therapy with Calcitriol and Cinacalcet HCl. Eight patients were recruited in whom conventional therapy was stable over the past 3 months. After a washout period of 2 weeks, calcijex injections were replaced by Paricalcitol. Paricalcitol induced more suppression of iPTH compared to the conventional therapy without significant hypercalcemia, hyperphosphatemia or side effects. The conversion ratio was approximately 1:2.5 (calcitriol:paricalcitol). In conclusion, injectable Paricalcitol is superior to Calcitriol in treatment of SHPT. Keywords: Cinacalcet, Calciferol, hemodialysis, hyperparathyroidism, Paricalcitol.