No

Vitamin D Analog

Management of hypocalcemia in patients on chronic renal dialysis; reduce elevated parathyroid hormone levels

C (per manufacturer); A/D (if dose exceeds RDA recommendation)(per expert analysis)

Hypercalcemia; vitamin D toxicity; abnormal sensitivity to the effects of vitamin D; malabsorption syndrome

Adequate dietary (supplemental) calcium is necessary for clinical response to vitamin D; maintain adequate fluid intake; calcium-phosphate product (serum calcium times phosphorus) must not exceed 70; avoid hypercalcemia or use with renal function impairment and secondary hyperparathyroidism

Percentage unknown: Hypotension, cardiac arrhythmias, hypertension, irritability, headache, somnolence, seizures (rare), pruritus, polydipsia, hypermagnesemia, nausea, vomiting, constipation, anorexia, pancreatitis, metallic taste, xerostomia, polyuria, elevated LFTs, myalgia, bone pain, conjunctivitis, photophobia

>10%: Endocrine & metabolic: Hypercalcemia (33%)

Rarely toxicity occurs from acute overdose. Symptoms of chronic overdose include hypercalcemia, hypercalciuria with weakness, altered mental status, GI upset, renal tubular injury, and occasionally cardiac arrhythmias.

Following withdrawal of the drug, treatment consists of bed rest, liberal intake of fluids, reduced calcium intake, and cathartic administration. Severe hypercalcemia requires I.V. hydration and forced diuresis. I.V. saline may increase excretion of calcium. Calcitonin, cholestyramine, prednisone, sodium EDTA, biphosphonates, and mithramycin have all been used successfully to treat the more resistant cases of vitamin D-induced hypercalcemia.

Decreased effect/absorption: Cholestyramine, colestipol

Increased effect: Thiazide diuretics

Additive effect: Magnesium-containing antacids

Store in tight, light-resistant container; calcitriol degrades upon prolonged exposure to light

Promotes absorption of calcium in the intestines and retention at the kidneys thereby increasing calcium levels in the serum; decreases excessive serum phosphatase levels, parathyroid hormone levels, and decreases bone resorption; increases renal tubule phosphate resorption

Onset of action: ~2-6 hours

Duration: 3-5 days

Absorption: Oral: Rapid

Metabolism: Primarily to 1,24,25-trihydroxycholecalciferol and 1,24,25-trihydroxy ergocalciferol

Half-life: 3-8 hours

Elimination: Principally in bile and feces with 4% to 6% excreted in urine

Individualize dosage to maintain calcium levels of 9-10 mg/dL

Children:

Oral: 0.25-2 mcg/day have been used (with hemodialysis); 0.014-0.041 mcg/kg/day (not receiving hemodialysis); increases should be made at 4- to 8-week intervals

I.V.: 0.01-0.05 mcg/kg 3 times/week if undergoing hemodialysis

Adults:

Oral: 0.25 mcg/day or every other day (may require 0.5-1 mcg/day); increases should be made at 4- to 8-week intervals

I.V.: 0.5 mcg/day 3 times/week (may require from 0.5-3 mcg/day given 3 times/week) if undergoing hemodialysis

Hypoparathyroidism/pseudohypoparathyroidism: Oral (evaluate dosage at 2- to 4-week intervals):

Children:

<1 year: 0.04-0.08 mcg/kg once daily

1-5 years: 0.25-0.75 mcg once daily

Children >6 years and Adults: 0.5-2 mcg once daily

Vitamin D-dependent rickets: Children and Adults: Oral: 1 mcg once daily

Vitamin D-resistant rickets (familial hypophosphatemia): Children and Adults: Oral: Initial: 0.015-0.02 mcg/kg once daily; maintenance: 0.03-0.06 mcg/kg once daily; maximum dose: 2 mcg once daily

Hypocalcemia in premature infants: Oral: 1 mcg once daily for 5 days

Hypocalcemic tetany in premature infants: I.V.: 0.05 mcg/kg once daily for 5-12 days

Monitor symptoms of hypercalcemia (weakness, fatigue, somnolence, headache, anorexia, dry mouth, metallic taste, nausea, vomiting, cramps, diarrhea, muscle pain, bone pain and irritability)

Calcium (serum) 9-10 mg/dL (4.5-5 mEq/L) but do not include the I.V. dosages; phosphate: 2.5-5 mg/dL

calcium, cholesterol, magnesium, BUN, AST, ALT, calcium (S), cholesterol (S); alkaline phosphatase

May cause sedation or irritability

None reported

No information available to require special precautions

No effects or complications reported

Take exact dose as prescribed; do not increase dose. Maintain recommended diet and calcium supplementation. Avoid taking magnesium-containing antacids. You may experience nausea, vomiting, loss of appetite, or metallic taste (frequent small meals, frequent mouth care, chewing gum, or sucking lozenges may help); or hypotension (use caution when rising from sitting or lying position or when climbing stairs or bending over). Report chest pain or palpitations; acute headache; skin rash; change in vision or eye irritation; CNS changes; unusual weakness or fatigue; persistent nausea, vomiting, cramps, or diarrhea; or muscle or bone pain.

May be administered as a bolus dose I.V. through the catheter at the end of hemodialysis

Monitor serum calcium and phosphate levels during therapy

Capsule: 0.25 mcg, 0.5 mcg

Injection: 1 mcg/mL (1 mL); 2 mcg/mL (1 mL)

Solution, oral: 1 mcg/mL

Letsou AP and Price LS, "Health Aging and Nutrition: An Overview," Clin Geriatr Med, 1987, 3(2):253-60.

Myrianthopoulos M, "Dietary Treatment of Hyperlipidemia in the Elderly," Clin Geriatr Med, 1987, 3(2):343-59.

Riggs BL and Melton LJ, "The Prevention and Treatment of Osteoporosis," N Engl J Med, 1992, 327(9):620-7.