CALCIFEDIOL (kal-si-fe-dye'ole) Calderol Classifications: hormone and synthetic substitute; vitamin d analog Prototype: Calcitriol Pregnancy Category: C
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20 mcg, 50 mcg capsules
Vitamin D analog and major transport form of cholecalciferol (D3) Vitamin D analog is fat soluble. Because it is activated in the body and has regulatory effects, it is considered a hormone.
Primary action leads to regulation of serum calcium, which is affected also by the activity of other vitamin D analogs (e.g.,
ergocalciferol), parathyroid hormone, and calcitonin. Pharmacologic effects of calcifediol are related to its intrinsic vitamin
D activity as well as to the properties of active metabolites (e.g., calcitriol), which result from renal metabolism.
Helps to maintain serum calcium in patients undergoing chronic renal dialysis and effective in renal osteodystrophy and promotes
healing in hepatic osteomalacia.
Management of metabolic bone disease and hypocalcemia associated with chronic renal failure in patients undergoing renal dialysis.
Osteopenia caused by prolonged glucocorticoid therapy and osteomalacia secondary to hepatic disease.
Hypersensitivity to vitamin D, vitamin D toxicity, hypercalcemia. Safe use of doses in excess of RDA during pregnancy (category
C), lactation, and children not established.
Patients receiving digitalis glycosides.
Metabolic Bone Disease in Patients With Chronic Renal Failure Adult: PO Initially 300350 mcg/wk administered on a daily or alternate day schedule, may increase at 4-wk intervals if necessary;
patients with normal calcium may only need 20 mcg q.o.d. (usual range 50100 mcg/d or 100200 mcg q.o.d.)
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Oral
- Since calcitriol is a metabolite of vitamin D3, all sources of vitamin D are usually withheld during therapy or at least must be considered when calculating dosage.
Body as a Whole: Muscle or bone pain, idiosyncratic reaction (headache, nausea, vomiting, diarrhea, fever). GI: Anorexia, nausea, vomiting, dry mouth, thirst, constipation, diarrhea, abdominal cramps, metallic taste. Metabolic: Vitamin D intoxication, hypercalcemia, polyuria, hypercalciuria, hyperphosphatemia. CNS: Lethargy, headache, weakness, vertigo.
Drug:
thiazide diuretics may cause hypercalcemia; may precipitate digitalis arrhythmias with digoxin.
Absorption: Readily absorbed from small intestines. Peak: 4 h. Duration: 1520 d. Distribution: Stored chiefly in liver and fat deposits. Metabolism: Activated in kidneys. Elimination: Excreted primarily in bile and feces. Half-Life: 1222 d.
Assessment & Drug Effects
- Lab tests: Determine baseline and periodic values for serum calcium, phosphorus, magnesium, and alkaline phosphatase. Monitor
serum calcium whenever dosage adjustments are made. Measure urinary calcium and phosphorus levels q24h.
- Effectiveness of therapy depends on an adequate daily intake of calcium. Since dietary calcium and phosphate are difficult
to control, the physician may prescribe a calcium supplement as needed.
- Monitor for manifestations of hypercalcemia (see Appendix F). If hypercalcemia occurs, discontinue calcifediol until serum
calcium returns to normal (910.6 mg/dL).
- Report a fall in serum alkaline phosphatase as this usually signals the onset of hypercalcemia.
Patient & Family Education
- Do not take this drug if experiencing S&S of hypercalcemia (see Appendix F), and report immediately to physician.
- Consult physician before taking an OTC medication. Calcium, phosphate, or magnesium-containing laxatives and antacids, mineral
oil, and vitamin D preparations may increase adverse effects of calcifediol and therefore should be avoided.
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Note: Patients undergoing dialysis may require aluminum carbonate or hydroxide gels to bind intestinal phosphate and thus lower
serum phosphate levels.
- Do not breast feed while taking this drug.