What it's for (Indications)
- This combination medication, containing alfacalcidol and calcium carbonate, is primarily indicated for the management of mineral and bone disorders associated with chronic kidney disease (CKD), including renal osteodystrophy.
- It is also utilized in the treatment of hypocalcemia and secondary hyperparathyroidism in patients with CKD, particularly those undergoing dialysis, where the renal hydroxylation of native vitamin D to its active form (calcitriol) is impaired.
- Furthermore, it may be prescribed for hypoparathyroidism, pseudohypoparathyroidism, and certain forms of osteoporosis, especially in patients with compromised vitamin D metabolism or inadequate dietary calcium intake.
- The alfacalcidol component provides a precursor to the active form of vitamin D, bypassing the renal 1-alpha-hydroxylation step, while calcium carbonate supplements essential elemental calcium, supporting bone health and correcting calcium deficiencies.
- This combination aims to restore calcium homeostasis, suppress elevated parathyroid hormone levels, and improve bone mineral density.
Dosage Information
| Type | Guideline |
|---|---|
| Standard | The dosage of alfacalcidol and calcium carbonate is highly individualized and must be carefully titrated based on the patient's serum calcium, phosphate, alkaline phosphatase, and parathyroid hormone (PTH) levels, as well as their clinical response and tolerance. Regular monitoring of these parameters is imperative to prevent hypercalcemia or other electrolyte imbalances. Typically, treatment is initiated with a low dose, with gradual increases at intervals of 2-4 weeks, until target calcium and PTH levels are achieved. For adults, common starting doses of alfacalcidol might range from 0.25 mcg to 1 mcg daily, often taken with meals to optimize calcium absorption and minimize gastrointestinal upset. Calcium carbonate dosage varies widely depending on the patient's dietary intake and specific calcium requirements, frequently ranging from 500 mg to 1500 mg of elemental calcium daily, divided into multiple doses. Close patient follow-up by a healthcare professional is essential to adjust the dose and monitor for adverse effects, especially in patients with impaired renal function. |
Safety & Warnings
Common Side Effects
- The most critical and commonly observed adverse effect associated with alfacalcidol and calcium carbonate therapy is hypercalcemia, which can range from mild asymptomatic elevation to severe, life-threatening complications.
- Symptoms of hypercalcemia include nausea, vomiting, constipation, abdominal pain, anorexia, polyuria, polydipsia, weakness, headache, drowsiness, and in severe cases, cardiac arrhythmias, confusion, and coma.
- Other gastrointestinal side effects may include dyspepsia, flatulence, and dry mouth.
- Renal complications such as nephrocalcinosis and nephrolithiasis (kidney stones) can occur with prolonged hypercalcemia, particularly in susceptible individuals.
- Hyperphosphatemia is another potential concern, especially in patients with chronic kidney disease if phosphate binding is inadequate.
- Less common side effects might include skin rash, metallic taste, and bone pain.
- Patients should be educated on the signs and symptoms of hypercalcemia and advised to report them immediately to their healthcare provider.
Serious Warnings
- Black Box Warning: **Serious Warnings: Risk of Hypercalcemia** This combined medication, containing alfacalcidol and calcium carbonate, carries a significant and serious risk of developing hypercalcemia. Hypercalcemia, or elevated blood calcium levels, can range from mild and asymptomatic to severe and life-threatening, manifesting as acute renal failure, cardiac arrhythmias, and central nervous system depression leading to coma. Due to the potent calcemic effects of alfacalcidol and the direct calcium load from calcium carbonate, continuous and rigorous monitoring of serum calcium concentrations is absolutely mandatory throughout the entire course of treatment, particularly during initial dose titration and whenever dosage adjustments are made. Patients must be thoroughly educated on the signs and symptoms of hypercalcemia, such as nausea, vomiting, constipation, polyuria, polydipsia, headache, and generalized weakness, and instructed to immediately report any such symptoms to their healthcare provider. If hypercalcemia occurs, prompt dose reduction or temporary cessation of the medication, along with appropriate supportive measures, is required to prevent serious adverse outcomes, including irreversible tissue calcification and potential organ damage. This warning emphasizes the critical need for diligent patient management and monitoring to ensure the safe and effective use of this therapy.
- This combination product requires careful clinical management due to the inherent risk of severe hypercalcemia.
- Regular and frequent monitoring of serum calcium, phosphate, magnesium, and parathyroid hormone (PTH) levels is absolutely essential throughout the treatment course, especially during dose initiation and adjustment.
- Patients with a history of hypercalcemia, nephrolithiasis, or nephrocalcinosis should be treated with extreme caution.
- Concomitant use of thiazide diuretics, which reduce calcium excretion, or digoxin, due to increased risk of cardiac arrhythmias with hypercalcemia, requires particular vigilance.
- Furthermore, patients taking other vitamin D derivatives or calcium supplements should be carefully evaluated to avoid additive effects.
- The product should be used cautiously in patients with conditions predisposing to hypercalcemia, such as granulomatous diseases (e.
- g.
- , sarcoidosis) or certain malignancies.
- Pregnancy and lactation also warrant careful consideration; benefits must clearly outweigh potential risks, and strict calcium monitoring is paramount.
- Patients must be educated about the importance of adhering to prescribed dosages and reporting any symptoms indicative of hypercalcemia promptly.
How it Works (Mechanism of Action)
Alfacalcidol is a synthetic analog of vitamin D that undergoes 25-hydroxylation in the liver to form 1,25-dihydroxyvitamin D3 (calcitriol), the biologically active form of vitamin D. Unlike native vitamin D, alfacalcidol bypasses the renal 1-alpha-hydroxylase step, which is often impaired in chronic kidney disease, making it highly effective in patients with renal insufficiency. Calcitriol exerts its effects by binding to the vitamin D receptor (VDR) in various target tissues. This binding leads to increased intestinal absorption of dietary calcium and phosphate, enhanced renal reabsorption of calcium in the distal tubules, and mobilization of calcium from bone. Calcitriol also plays a crucial role in regulating parathyroid hormone (PTH) secretion, directly suppressing its synthesis and release, thereby mitigating secondary hyperparathyroidism. Calcium carbonate acts as a direct calcium supplement, providing elemental calcium for absorption into the systemic circulation. It also functions as a phosphate binder in the gastrointestinal tract, forming insoluble calcium-phosphate complexes that reduce dietary phosphate absorption, which is particularly beneficial in chronic kidney disease patients to manage hyperphosphatemia.
Commercial Brands (Alternatives)
No other brands found for this formula.