Trade Names:Calcijex- Injection 1 mcg/mL
Trade Names:Calcitriol Injection- Injection 2 mcg/mL
Trade Names:Rocaltrol- Capsules 0.25 mcg- Capsules 0.5 mcg- Solution, oral 1 mcg/mL
Trade Names:Vetical- Ointment 3 mcg/g
Supply of vitamin D depends mainly on exposure to UV rays of the sun for conversion of 7-dehydrocholesterol in the skin to vitamin D 3 (cholecalciferol). Vitamin D 3 is activated in the liver and kidney before fully active as a regulator of calcium and phosphorus metabolism at target tissues. The mechanism of action in the treatment of psoriasis has not been established.
Rapidly absorbed from the intestine. T max is 3 to 6 h.
Approximately 99.9% protein bound.
The first pathway involves 24-hydroxylase to produce calcitroic acid; the second pathway involves hydroxylation and cyclization.
The half-life is about 5 to 8 h. About 27% is excreted in the feces and 7% in the urine within 24 h.
The half-life is increased by at least 2-fold.
Hepatic Function ImpairmentStudies have not been conducted.
ElderlyStudies have not been conducted.
ChildrenThe half-life is prolonged.
GenderStudies have not been conducted.
Hypocalcemia and resultant metabolic bone disease in patients on chronic renal dialysis.
Predialysis (Oral)Secondary hyperparathyroidism and resultant metabolic bone disease in patients with moderate to severe chronic renal failure (CrCl 15 to 55 mL/min) not yet on dialysis.
Hypoparathyroidism (Oral)Hypocalcemia in patients with postsurgical hypoparathyroidism, idiopathic hypoparathyroidism, and pseudohypoparathyroidism.
Psoriasis (Topical)Treatment of mild to moderate plaque psoriasis.
Management of psoriatic lesions.
Hypercalcemia or patients with vitamin D toxicity; hypersensitivity to any component of this product.
PO 0.25 mcg/day. If all unsatisfactory response, increase dose by 0.25 mcg/day at 4- to 8-wk intervals. Obtain serum calcium levels at least twice weekly during this titration. If hypercalcemia occurs, immediately discontinue treatment until normocalemia is obtained. Normal or only slightly reduced calcium levels may respond to dosages of 0.25 mcg every other day.
IV 0.02 mcg/kg (1 to 2 mcg) 3 times/wk, every other day. May increase 0.5 to 1 mcg, every 2 to 4 wk. During this titration, obtain serum calcium levels twice weekly.
PredialysisAdults and Children (older than 3 years of age)PO Initial dosage is 0.25 mcg/day in adults and children older than 3 yr of age. Dosage may be increased up to 0.5 mcg/day.
Children younger than 3 years of agePO 10 to 15 mg/kg/day.
HypoparathyroidismPO Initial dosage is 0.25 mcg/day in the morning. If unsatisfactory response, increase dose at 2- to 4-wk intervals. During this titration, obtain serum calcium levels 2 times/wk. If hypercalcemia occurs, immediately discontinue treatment until normocalemia is obtained.
Adults and children (6 yr of age and older)PO 0.5 to 2 mcg daily.
Children (1 to 5 yr of age)PO Usually given 0.25 to 0.75 mcg daily.
PsoriasisAdultsTopical Apply to affected areas twice daily, morning and evening (max, 200 g/week).
Store at 59° to 86°F. Protect from light. Do not freeze or refrigerate ointment.
Avoid uncontrolled intake of additional calcium-containing preparations.
CholestyramineMay reduce intestinal absorption of fat-soluble vitamins.
CorticosteroidsCalcium absorption–promoting effects of calcitriol may be antagonized by corticosteroids, which inhibit calcium absorption.
DigitalisUse with caution; may precipitate cardiac arrhythmias.
KetoconazoleMay reduce endogenous calcitriol concentrations.
MagnesiumMagnesium-containing products may cause hypermagnesemia and should be avoided during calcitriol administration to patients on chronic renal dialysis.
Phenytoin/PhenobarbitalInhibits endogenous synthesis of calcitriol; therefore, may require higher doses calcitriol if given simultaneously.
Phosphate-binding agentsBecause phosphate transport in the intestine, kidneys, and bones may be affected, the dosage of phosphate-binding agents must be adjusted based on serum phosphate concentration.
ThiazidesKnown to induce hypercalcemia by the reduction of calcium excretion.
VerapamilTherapeutic effects of verapamil may be reduced.
Vitamin DTo avoid possible additive effects and hypercalcemia, withhold pharmacologic doses of vitamin D and its derivatives.
None well documented.
Psoriasis (4%); pruritus (3%); acute blistering dermatitis, erythema, skin burning sensations, skin discomfort (postmarketing).
Elevated serum creatinine levels.
TopicalUrine abnormality (4%); hypercalciuria (3%).
Anaphylaxis (postmarketing).
Hypercalcemia (24%); abnormal lab tests (8%).
Skin discomfort (3%).
Hypersensitivity (pruritis, rash, severe erythematous skin disorder, urticaria, [rare]), erythema multiforme, allergic reaction (eg, hives, swelling of the lips); soft tissue calcification.
Category C .
Excreted.
Safety and efficacy not established in dialysis patients; dosing guidelines for oral calcitriol have not been established in children younger than 1 year of age with hypoparathyroidism or younger than 6 years of age with pseudohypoparathyroidism.
OintmentSafety and efficacy not established in children.
Dose selection should be cautious, starting at the low end of the dosage range.
May occur.
With use of the ointment, patients should avoid excessive exposure of treated areas to either natural or artificial sunlight, including sunlamps and tanning booths.
Adverse reactions are associated with excessive intake. The early stage symptoms of toxicity include the following: weakness, headache, somnolence, nausea, vomiting, dry mouth, constipation, muscle pain, bone pain, metallic taste, anorexia, abdominal pain, stomach ache. The late stage symptoms of toxicity include the following: cardiac arrhythmias, hypertension, pruritus, conjunctivitis (calcific), anorexia, weight loss, pancreatitis, polyuria, polydipsia, nocturia, elevated BUN, nephrocalcinosis, hypercholesterolemia, elevated AST/ALT, albuminia, decreased libido, hyperthermia, photophobia, rhinorrhea, ectopic calcification, overt psychosis, dystrophy, sensory disturbances, dehydration, apathy, arrested growth, UTI, hypercalcemia, hypercalciuria, hyperphosphatemia, overt psychosis (rare).
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