DOXERCALCIFEROL
| DOXERCALCIFEROL (dox-er-kal'si-fe-rol) Hectorol Classifications: vitamin d analog; Therapeutic:antihyperparathyroid agent; vitamin d analog Prototype: Calcitriol Pregnancy Category: B |
Availability
0.5 mcg, 2.5 mcg capsule; 2 mcg/mL injection
Action
Vitamin D2 analog that is activated by the liver. Activated vitamin D is needed for absorption of dietary calcium in the intestine, and the parathyroid hormone (PTH), which mobilizes calcium from the bone tissue.
Therapeutic Effect
Regulates the blood calcium level.
Uses
Reduction of elevated iPTH in secondary hyperparathyroidism in patients undergoing chronic renal dialysis; secondary hyperparathyroidism in chronic kidney disease not on dialysis.
Contraindications
Hypersensitivity to doxercalciferol or other vitamin D analogs; recent hypercalcemia, recent hyperphosphatemia, hypervitaminosis D.
Cautious Use
Renal or hepatic insufficiency; renal osteodystrophy with hyperphosphatemia, prolonged hypercalcemia; pregnancy (category B), lactation. Safety and efficacy in children are not established.
Route & Dosage
| Secondary Hyperparathyroidism Adult: PO 10 mcg 3 times/wk at dialysis, adjust dose as needed to lower iPTH into the range of 150–300 pg/mL by increasing the dose in 2.5 mcg increments every 8 wk (max: 60 mcg/wk) IV 4 mcg 3 times/wk at end of dialysis (max: 18 mcg/wk) |
Administration
Oral- Give at time of dialysis.
- Withhold drug and notify physician if any of the following occurs: iPTH <100 pg/mL, hypercalcemia, hyperphosphatemia, or product of serum calcium times serum phosphorus >70.
- Use beyond 16 wk is not recommended.
- Store at 20°–25° C (66°–77° F); excursions to 15°–30° C (59°–86° F) are permitted.
| Intravenous PREPARE: Direct: ??No dilution is needed.??Withdraw appropriate dose from ampule using a filter needle.??Change needles before injecting as an IV bolus. Discard any unused portion. ADMINISTER: Direct: Give a bolus injection at the end of dialysis sessions. |
- Store at 15°–20° C (59°–77° F).
Adverse Effects (≥1%)
Body as a Whole: Abscess, headache, malaise, arthralgia. CNS: Dizziness, sleep disorder. CV: Bradycardia, edema. GI: Anorexia, constipation, dyspepsia, nausea, vomiting. Respiratory: Dyspnea. Skin: Pruritus. Other: Weight gain.Interactions
Drug: Cholestyramine, mineral oil may decrease absorption; magnesium-containing antacids may cause hypermagnesemia; other vitamin d analogs may increase toxicity and hypercalcemia.Pharmacokinetics
Absorption: Absorbed from GI tract and is activated in the liver. Peak: 11–12 h. Metabolism: Activated by CYP 27 to form 1alpha, 25-(OH)2D2 (major metabolite) and 1alpha, 24-dihydroxyvitamin D2 (minor metabolite). Half-Life: 32–37 h.Nursing Implications
Assessment & Drug Effects
- Lab tests: Baseline and periodic iPTH, serum calcium, serum phosphorus. Monitor levels weekly during dose titration.
- Monitor for S&S of hypercalcemia (see Appendix F).
Patient & Family Education
- Do not take antacids without consulting the physician.
- Notify the physician if you become pregnant while taking this drug.
- Do not use mineral oil on the days doxercalciferol is taken. Mineral oil may decrease absorption of drug.
- Do not take nonprescription drugs containing magnesium while taking doxercalciferol.
- Report S&S of hypercalcemia immediately: Bone or muscle pain, dry mouth with metallic taste, rhinorrhea, itching, photophobia, conjunctivitis, frequent urination, anorexia and weight loss.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; 
Canadian drug name; 
Prototype drug