Overview
11 DESCRIPTION Paricalcitol, USP, the active ingredient in Paricalcitol Capsules, is a synthetically manufactured, metabolically active vitamin D analog of calcitriol with modifications to the side chain (D 2 ) and the A (19-nor) ring. Paricalcitol is available as soft gelatin capsules for oral administration containing 1 microgram, 2 micrograms, and 4 micrograms of paricalcitol.
Mechanism of Action
12 CLINICAL PHARMACOLOGY Secondary hyperparathyroidism is characterized by an elevation in parathyroid hormone (PTH) associated with inadequate levels of active vitamin D hormone. The source of vitamin D in the body is from synthesis in the skin as vitamin D 3 and from dietary intake as either vitamin D 2 or D 3 . Both vitamin D 2 and D 3 require two sequential hydroxylations in the liver and the kidney to bind to and to activate the vitamin D receptor (VDR). The endogenous VDR activator, calcitriol [1,25(OH) 2 D 3 ], is a hormone that binds to VDRs that are present in the parathyroid gland, intestine, kidney, and bone to maintain parathyroid function and calcium and phosphorus homeostasis, and to VDRs found in many other tissues, including prostate, endothelium and immune cells.
Indications
- 1 INDICATIONS & USAGE 1.1 Chronic Kidney Disease Stages 3 and 4 Paricalcitol Capsules are indicated in adults for the prevention and treatment of secondary hyperparathyroidism associated with Chronic Kidney Disease (CKD) Stages 3 and 4. Pediatric use information for patients 10 to 16 years of age is approved for AbbVie Inc.’s Zemplar (Paricalcitol) capsules. However, due to AbbVie Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information. 1.
Common Doses
- 1 mcg
- 2 mcg
- 4 mcg
- 9.5 mg
Dosage
2 DOSAGE & ADMINISTRATION 2.1 Chronic Kidney Disease Stages 3 and 4 in Adults Administer Paricalcitol Capsules orally once daily or three times a week. [see Clinical Studies (14.1)] . When dosing three times weekly, do not administer more frequently than every other day. Initial Dose Table 1. Recommended Paricalcitol Capsules Starting Dose Based upon Baseline iPTH Level Baseline iPTH Level Daily Dose Three Times a Week Dose* Less than or equal to 500 pg/mL 1 mcg 2 mcg More than 500 pg/mL 2 mcg 4 mcg * To be administered not more often than every other day Dose Titration Table 2.
Contraindications
- 4 CONTRAINDICATIONS Paricalcitol Capsules should not be given to patients with evidence of hypercalcemia or vitamin D toxicity [see Warnings and Precautions (5.1)]. Evidence of hypercalcemia (4). Evidence of vitamin D toxicity (4).
Side Effects
- 6 ADVERSE REACTIONS Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice. 6.1 Clinical Trials Experience CKD Stages 3 and 4 Adults The safety of Paricalcitol Capsules has been evaluated in three 24-week (approximately six-month), double-blind, placebo-controlled, multicenter clinical studies involving 220 CKD Stages 3 and 4 patients.
Interactions
- 7 DRUG INTERACTIONS Table 5 shows the clinically significant drug interactions with Paricalcitol capsules. Table 5: Clinically Significant Drug Interactions with Paricalcitol CYP3A Inhibitors Clinical Impact Paricalcitol is partially metabolized by CYP3A. Hence, exposure of paricalcitol will increase upon coadministration with strong CYP3A inhibitors such as but not limited to: boceprevir, clarithromycin, conivaptan, grapefruit juice, indinavir, itraconazole, ketoconazole, lopinavir/ritonavir, mibefradil, nefazodone, nelfinavir, posaconazole, ritonavir, saquinavir, telaprevir, telithromycin,...