PARICALCITOL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PARICALCITOL (PARICALCITOL).
Paricalcitol is a synthetic vitamin D analog that binds to the vitamin D receptor (VDR) in target tissues, including the parathyroid glands, kidneys, and intestines. It selectively activates VDR to suppress parathyroid hormone (PTH) secretion, reduce parathyroid cell proliferation, and modulate calcium and phosphate homeostasis with lower calcemic and phosphatemic effects compared to calcitriol.
| Metabolism | Primarily metabolized by hepatic enzymes, including CYP24A1 and CYP3A4, to inactive metabolites. Less than 1% of the drug is excreted unchanged in urine. |
| Excretion | Primarily fecal (74%) via hepatobiliary excretion; renal elimination accounts for approximately 16% as unchanged drug. |
| Half-life | Terminal elimination half-life is approximately 5-7 hours in healthy subjects, but may be prolonged to 14-20 hours in patients with renal impairment. |
| Protein binding | Approximately 99% bound to plasma proteins, primarily to albumin. |
| Volume of Distribution | Volume of distribution is 0.4-0.6 L/kg, indicating limited extravascular distribution. |
| Bioavailability | Oral bioavailability is approximately 72-79% under fasting conditions. |
| Onset of Action | Intravenous: within 2-4 hours for suppression of parathyroid hormone (PTH). Oral: onset within 6-12 hours. |
| Duration of Action | Intravenous: duration of PTH suppression persists for 24 hours. Oral: effect lasts 12-24 hours. |
0.04 to 0.1 mcg/kg intravenously bolus no more frequently than every other day during dialysis, or 1 to 4 mcg orally once daily.
| Dosage form | SOLUTION |
| Renal impairment | No adjustment required for renal impairment as drug is hepatically cleared; however, monitor serum calcium and phosphorus closely in patients with severe renal impairment. |
| Liver impairment | Child-Pugh Class A or B: no adjustment; Child-Pugh Class C: reduce dose by 50%. |
| Pediatric use | 0.04 to 0.1 mcg/kg intravenously no more frequently than every other day; maximum 0.24 mcg/kg per dose. Oral: 1 to 4 mcg once daily based on PTH levels. |
| Geriatric use | Start at low end of dosing range (0.04 mcg/kg IV or 1 mcg oral daily) due to potential for increased sensitivity; monitor calcium and phosphorus frequently. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PARICALCITOL (PARICALCITOL).
| Breastfeeding | Excretion in breast milk unknown. Paricalcitol is lipophilic and may concentrate in milk. Caution advised due to potential hypercalcemia in infant. M/P ratio not available. |
| Teratogenic Risk | Paricalcitol is a vitamin D analog; fetal risk cannot be ruled out. In animal studies, doses 0.5-2 times the human exposure caused reduced fetal weight and skeletal ossification. No adequate human studies in pregnancy. Use only if benefit outweighs risk, especially during first trimester. |
| Fetal Monitoring |
■ FDA Black Box Warning
No FDA black box warning.
| Common Effects | Nausea Fatigue Dryness in mouth Loss of appetite Increased sweating Dizziness Nervousness Tremors Low sexual desire Insomnia difficulty in sleeping Confusion Constipation Erectile dysfunction Delayed ejaculation Decreased libido |
| Serious Effects |
["Hypercalcemia","Hypersensitivity to paricalcitol or any component of the formulation","Vitamin D toxicity","Hypersensitivity reactions (rare)"]
| Precautions | ["Hypercalcemia: Monitor serum calcium, phosphate, and PTH levels regularly; dose reduction or discontinuation may be necessary.","Digitalis toxicity: Hypercalcemia may potentiate digitalis toxicity; use with caution.","Adynamic bone disease: Oversuppression of PTH may lead to adynamic bone disease; adjust dosing to maintain PTH levels within target range.","Aluminum overload: Avoid concomitant use with aluminum-containing phosphate binders due to increased risk of aluminum toxicity.","Drug interactions: Caution with other drugs that affect calcium metabolism (e.g., thiazide diuretics, calcitonin)."] |
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| Monitor serum calcium, phosphorus, and intact PTH levels regularly during pregnancy. Also monitor fetal growth via ultrasound if used long-term. |
| Fertility Effects | Animal studies show no impairment of fertility at doses up to 20 mcg/kg/day. Human data lacking. |