Generic
Calcitriol
15 brands available in the market
At a glance
Calcitriol is the active form of Vitamin D that increases Vitamin D and calcium levels in the blood. It is used in the treatment of postmenopausal osteoporosis, renal osteodystrophy, hypoparathyroidism, and vitamin D-dependent rickets.
Description
Calcitriol is one of the most important active metabolites of vitamin D3. It is normally formed in the kidneys from its precursor, 25-hydroxycholecalciferol. Calcitriol promotes intestinal absorption of calcium and regulates bone mineralization. The key role of calcitriol is the regulation of calcium homeostasis, which includes stimulation effects on osteoblastic activity in the skeleton.
Calcitriol is indicated in post-menopausal osteoporosis, renal osteodystrophy (dialysis patients), postsurgical hypoparathyroidism, idiopathic hypoparathyroidism, pseudohypoparathyroidism, secondary hyperparathyroidism in patients with moderate to severe chronic renal failure (pre-dialysis), and vitamin D-dependent rickets.
Indications
- Post-menopausal osteoporosis
- Renal osteodystrophy
- Postsurgical hypoparathyroidism
- Idiopathic hypoparathyroidism
- Pseudohypoparathyroidism
- Secondary hyperparathyroidism in chronic renal failure
- Vitamin D dependent rickets
Therapeutic class
Vitamin-D preparations
Pharmacological class
Vitamin D Analog (Active Metabolite)
Pharmacology
Calcitriol is the active metabolite of vitamin D3 that increases intestinal calcium absorption, enhances renal calcium retention, and regulates bone mineralization. It plays a key role in calcium homeostasis and stimulates osteoblastic activity in the skeleton.
Mechanism of action
Calcitriol promotes intestinal calcium absorption, increases renal calcium retention, and regulates bone mineralization, thereby increasing serum calcium levels. It also increases renal tubule phosphate resorption, decreasing serum phosphatase, PTH levels, and bone resorption.
Dosage
Postmenopausal Osteoporosis: 0.25 mcg twice daily OR 0.50 mcg once daily.
Renal Osteodystrophy (Dialysis patients): Initial 0.25 mcg/day; normal or slightly reduced calcium: 0.25 mcg every other day; hemodialysis patients: 0.5-1 mcg/day.
Hypoparathyroidism & Rickets: Initial 0.25 mcg/day (morning); increase every 2-4 weeks if needed.
Secondary Hyperparathyroidism (Pre-dialysis): 0.25 mcg/day; may increase to 0.5 mcg/day if needed.
Hypocalcemia in Premature Infants: 1 mcg/day (oral) for 5 days.
Injection (IV): 1-2 mcg three times weekly (approximately every other day); doses of 0.5-4 mcg have been used. Increase by 0.5-1 mcg every 2-4 weeks if needed.
Serum creatinine monitoring: At 4 weeks, 3 and 6 months, and every 6 months thereafter.
Administration
Capsule: Dose determined by physician based on serum calcium levels. Injection: For IV administration only, administered by healthcare professional.
Missed dose
If you miss a dose, take it as soon as you remember. Skip the missed dose if it is almost time for your next dose. Do not double the dose.
Side effects
Early side effects: Weakness, headache, somnolence, nausea, vomiting, dry mouth, constipation, muscle pain, bone pain, metallic taste.
Late side effects: Polyuria, polydipsia, anorexia, weight loss, nocturia, conjunctivitis (calcific), pancreatitis, photophobia, rhinorrhea, pruritus, hyperthermia, decreased libido, elevated BUN, albuminuria, hypercholesterolemia, elevated SGOT/SGPT, ectopic calcification, hypertension, cardiac arrhythmias, rarely psychosis.
Mild pain on injection may occur.
Precautions & warnings
- Excessive dosage may cause hypercalcemia; caution in patients on digitalis (hypercalcemia may precipitate cardiac arrhythmias).
- Withhold vitamin D and its derivatives during treatment.
- Use non-aluminum phosphate-binding compounds to control serum phosphorus in dialysis patients.
- Chronic hypercalcemia may lead to vascular calcification, nephrocalcinosis, and soft-tissue calcification.
- If hypercalcemia develops, discontinue immediately.
- Avoid antacids (magnesium-containing antacids may cause hypermagnesemia).
- Drink plenty of fluids (avoid dehydration).
Contraindications
- Hypercalcemia (serum calcium > normal range)
- Evidence of vitamin D toxicity
- Pregnancy (doses exceeding RDA)
- Lactation
- Hypersensitivity to any ingredient
Drug interactions
- Thiazide diuretics: Increased risk of hypercalcemia.
- Digitalis: Hypercalcemia may precipitate cardiac arrhythmias; caution required.
- Magnesium-containing antacids: May cause hypermagnesemia.
- Cholestyramine and colestipol: May reduce intestinal absorption of calcitriol.
- Phenytoin, barbiturates: May decrease calcitriol half-life.
Food interactions
Caution is advised when consuming alcohol with Calcitriol; drink plenty of fluids to avoid dehydration.
Use in pregnancy
May be unsafe during pregnancy (Category C). Limited human studies available; animal studies have shown harmful effects. Vitamin D has not been shown to be teratogenic in humans, but use only if benefits outweigh risks.
Pregnancy Category: C — always consult a doctor before taking during pregnancy.
Use in lactation
Safe during breastfeeding. Human studies suggest the drug does not pass into breast milk in significant amounts and is not harmful to the baby. However, serum calcium levels of both mother and infant should be monitored.
Pediatric use
Geriatric use
No dose adjustment required for elderly.
Renal / hepatic impairment
Hepatic impairment: Safe; no dose adjustment required.
Overdose effects
Overdose may cause hypercalcemia, hypercalciuria, and hyperphosphatemia. Treatment of hypercalcemia (>1 mg/dL): immediate discontinuation of calcitriol, low calcium diet, and withdrawal of calcium supplements.
Storage conditions
Store in a dry place away from light and heat. Keep out of reach of children.
Chemical structure
Calcitriol (1,25-Dihydroxycholecalciferol)