Rocaltrol, Calcijex, Oscal
Generic Name
Calcitriol
Manufacturer
Many generic manufacturers
Country
Global
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Description
Overview of the medicine
Calcitriol is a synthetic active form of Vitamin D3 (1,25-dihydroxycholecalciferol) used to treat conditions caused by impaired calcium metabolism and parathyroid hormone issues. It helps regulate calcium and phosphate levels in the body.
Uses & Indications
Dosage
Adults
For chronic renal dialysis patients: Initially 0.25 mcg daily. Dosage may be increased by 0.25 mcg/day at 2- to 4-week intervals. Most patients respond to 0.5-1 mcg/day. For hypoparathyroidism: Initially 0.25 mcg daily, adjusted based on serum calcium levels.
Elderly
Similar to adults, but close monitoring of serum calcium and phosphate is recommended due to potential for greater sensitivity.
Renal_impairment
Careful individual titration required based on serum calcium, phosphate, and PTH levels.
How to Take
Oral capsules can be taken with or without food. Injectable solution is administered intravenously. Do not crush or chew capsules.
Mechanism of Action
Calcitriol binds to and activates the vitamin D receptor (VDR) in target tissues like the intestine, kidney, and bone. This action promotes intestinal absorption of calcium and phosphate, regulates renal reabsorption of calcium and phosphate, and affects bone mineralization and remodeling. It also suppresses parathyroid hormone (PTH) secretion.
Pharmacokinetics
Onset
Therapeutic effects are typically observed within 2-4 days.
Excretion
Excreted primarily through the bile into the feces (about 70%) and a small amount through the kidneys in urine (about 30%).
Half life
The elimination half-life is approximately 5 to 8 hours.
Absorption
Rapidly absorbed from the gastrointestinal tract following oral administration. Peak plasma concentrations are reached within 3 to 6 hours.
Metabolism
Metabolized in the liver and kidney by hydroxylation to inactive metabolites.
Side Effects
Contraindications
- •Hypercalcemia (abnormally high levels of calcium in the blood).
- •Vitamin D toxicity.
- •Hypersensitivity to Calcitriol or any components of the formulation, or to other vitamin D analogues.
Drug Interactions
Corticosteroids
May counteract the effects of vitamin D analogues.
Thiazide diuretics
Concurrent use may increase the risk of hypercalcemia.
Digitalis glycosides
Hypercalcemia in patients taking digitalis may precipitate cardiac arrhythmias.
Phenobarbital, Phenytoin
May increase calcitriol metabolism, requiring higher doses.
Cholestyramine, Mineral Oil
May impair intestinal absorption of Calcitriol.
Magnesium-containing antacids
Avoid in patients on dialysis due to potential for hypermagnesemia.
Storage
Store at controlled room temperature (15-30°C or 59-86°F). Protect from light and moisture. Do not freeze.
Overdose
Symptoms of overdose include hypercalcemia (nausea, vomiting, loss of appetite, constipation, polyuria, polydipsia, weakness, headache, confusion, fatigue). Management involves immediate discontinuation of calcitriol, a low calcium diet, and aggressive hydration. Monitor serum calcium levels frequently.
Pregnancy & Lactation
Pregnancy Category C. Use only if the potential benefit justifies the potential risk to the fetus. Calcitriol is excreted in breast milk; therefore, caution should be exercised when administered to a nursing woman.
Frequently Asked Questions
Common questions about this medicine
Pack Sizes
Shelf Life
Varies by specific formulation and manufacturer, typically 2-3 years.
Availability
Pharmacies, Hospitals
Approval Status
Approved
Patent Status
Off-patent
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Global Brand Names
International brand names for this medicine
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