Vitamin D Research Today is a free monthly online journal that collates and summarizes the latest research about Vitamin D, including details on sources, melanin, benefits, deficiency, supplements, calcium absorption.

Effect of omeprazole on the pharmacokinetics of paricalcitol in healthy subjects.

Palaparthy R, Pradhan RS, Chan J, Rieser M, Chira T, Galitz L, Awni W, Williams LA

Department of Clinical Pharmacology and Pharmacometrics, Abbott, Abbott Park, IL 60064, USA. rameshraja.palaparthy@abbott.com

Paricalcitol capsules are indicated for the prevention and treatment of secondary hyperparathyroidism in chronic kidney disease (CKD). Proton pump inhibitors are prescribed to CKD patients to treat gastroesophageal reflux. This was a single dose, crossover study evaluating the effect of omeprazole, change in gastric pH as a result thereof, on the pharmacokinetics (PK) of paricalcitol. Twenty-six healthy subjects were administered paricalcitol capsules (16 microg) alone (regimen A), and following a single dose of OMP (40 mg) (regimen B), with a washout of at least 7 days. Plasma samples for paricalcitol concentrations were collected for 48 h post-paricalcitol dose. The plasma paricalcitol concentrations were measured using an LC-MS/MS assay (LOQ=0.02 ng/ml) and paricalcitol pharmacokinetic parameters were estimated using non-compartmental methods. The point estimates and the corresponding 90% confidence intervals for Cmax and AUC0-infinity to evaluate paricalcitol-omeprazole interaction were 1.032 [0.920-1.158] and 1.041 [0.951-1.139], respectively. No significant differences in Tmax (regimen A: 2.9 h vs regimen B: 2.6 h) or t1/2 (6.83 h vs 6.6 h) between the regimens were observed. Hence, the co-administration of omeprazole does not affect the PK of paricalcitol. Both regimens were well tolerated and no apparent differences among the regimens with respect to safety were observed.

Published 27 February 2007 in Biopharm Drug Dispos, 28(2): 65-71.
Full-text of this article is available online (may require subscription).

© 2004-2008 Vitamin D Research Today. All Rights Reserved.