Drug Guide
Paricalcitol
Classification
Therapeutic: Vitamin D analog for secondary hyperparathyroidism in chronic kidney disease
Pharmacological: Vitamin D receptor agonist
FDA Approved Indications
- Treatment of secondary hyperparathyroidism in patients with chronic kidney disease (CKD) on dialysis
Mechanism of Action
Paricalcitol binds to vitamin D receptors, reducing parathyroid hormone (PTH) synthesis and secretion, thereby controlling secondary hyperparathyroidism without significantly increasing serum calcium and phosphate levels.
Dosage and Administration
Adult: Initial dose: 2-3 mcg intravenously or orally three times a week at dialysis: adjust based on PTH levels, calcium, and phosphate; maintenance dose varies.
Pediatric: Use not established; data limited.
Geriatric: No specific dose adjustments required, but renal function and serum calcium/phosphate levels should be monitored closely.
Renal Impairment: Adjust dose based on PTH, calcium, and phosphate levels; more frequent monitoring recommended.
Hepatic Impairment: No specific adjustments necessary.
Pharmacokinetics
Absorption: Oral bioavailability approximately 70%; IV administration bypasses absorption.
Distribution: Bound to vitamin D binding protein in plasma.
Metabolism: Partially metabolized in the liver; undergoes phase I and phase II reactions.
Excretion: Excreted primarily in feces; minimal urinary excretion.
Half Life: Approximately 5-7 days.
Contraindications
- Known hypersensitivity to paricalcitol or any component of the formulation.
Precautions
- Monitor for hypercalcemia, especially in patients with vitamin D toxicity risk.
- Use with caution in patients prone to hyperphosphatemia.
- Adjust doses based on serum calcium, phosphate, and PTH levels.
Adverse Reactions - Common
- Hypercalcemia (Common)
- Nausea (Less common)
- Vomiting (Less common)
Adverse Reactions - Serious
- Serious hypercalcemia requiring discontinuation (Rare)
- Cardiovascular issues related to hypercalcemia (e.g., arrhythmias) (Rare)
Drug-Drug Interactions
- Thiazide diuretics (risk of hypercalcemia)
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor serum levels of calcium, phosphate, and PTH before and during therapy.
Diagnoses:
- Risk for hypercalcemia
- Risk for electrolyte imbalance
Implementation: Administer as prescribed, monitor labs regularly, educate patient about signs of hypercalcemia.
Evaluation: Adjust dosage based on lab results and clinical response.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report symptoms of hypercalcemia such as nausea, vomiting, weakness, confusion.
- Maintain regular blood tests as scheduled.
Special Considerations
Black Box Warnings:
- Risk of hypercalcemia, which can lead to vascular and tissue calcification.
Genetic Factors: No specific genetic considerations.
Lab Test Interference: May affect calcium and phosphate measurements; interpret labs with clinical context.
Overdose Management
Signs/Symptoms: Severe hypercalcemia, including nausea, vomiting, weakness, confusion, arrhythmias.
Treatment: Discontinue drug, provide hydration, and use medications such as bisphosphonates if necessary; manage hypercalcemia symptomatically.
Storage and Handling
Storage: Store at 20-25°C (68-77°F); protect from light.
Stability: Stable under recommended storage conditions for the duration of the shelf life.