Indications
Vitamin D3 deficiency is common in individuals with limited sunlight exposure or insufficient dietary intake of vitamin D3. This vital nutrient is crucial for the optimal absorption of calcium and phosphate, essential for maintaining healthy bones and teeth, and preventing conditions such as rickets, osteomalacia, and osteoporosis. Additionally, adequate vitamin D3 levels are important during pregnancy to prevent pre-eclampsia and support the nutritional needs of a growing infant. Furthermore, vitamin D3 plays a significant role in boosting the immune system.
- Consult a registered physician for medication advice.
Pharmacology
The active form of Vitamin D3, Calcitriol, exerts its effects by binding to Vitamin D receptors (VDRs) present in various body tissues. As a fat-soluble vitamin, Vitamin D3 has a half-life of approximately 50 days. It is absorbed in the small intestine, where it binds to specific alpha-globulins and is then transported to the liver, where it is converted to 25-hydroxy Vitamin D3 (Calcidiol). A second hydroxylation occurs in the kidneys, transforming it into 1,25-dihydroxy Vitamin D3 (Calcitriol), the active metabolite responsible for enhancing calcium absorption. Any unutilized Vitamin D3 is stored in fat and muscle tissues and eliminated through feces and urine.
Dosage & Administration
For Capsules:
- Adults:
- Vitamin D3 Deficiency Treatment: 40,000 IU once weekly for 7 weeks. Maintenance dosage ranges from 1,400 to 2,000 IU/day. Confirm target levels of 25-hydroxyvitamin D after 3-4 months of maintenance therapy.
- Prevention of Deficiency: 20,000 IU every 4 weeks, with higher doses as necessary.
- Osteoporosis Therapy Supplement: 20,000 IU once a month.
- Children (12-18 years):
- Deficiency Treatment: 20,000 IU once every 2 weeks for 6 weeks.
- Prevention of Deficiency: 20,000 IU every 6 weeks.
For Film-Coated Tablets:
- 1,000 IU (1-2 tablets) daily, or as directed by a physician. Take with food or within 1 hour post-meal.
For Oroflash or Chewable Tablets:
- 1,000 IU to 2,000 IU daily, or as directed by a physician. Consume with food or within 1 hour after a meal. Chew thoroughly before swallowing.
For Syrup:
- At-Risk Patients:
- 0-1 Year: 400 IU/day (2 ml).
- >1 Year: 600 IU/day (3 ml).
- Deficient Patients:
- 0-1 Year: 2,000 IU/day (+50,000 IU/week) for 6 weeks.
- 1-18 Years: 2,000 IU/day for 6 weeks.
For Injection:
- Prevention:
- Infants on Vitamin D-enriched Milk: ½ ampoule (0.5 ml), equivalent to 100,000 IU, every 6 months.
- Nursed Infants or Non-enriched Milk Infants up to 5 Years: 1 ampoule (1 ml), equivalent to 200,000 IU, every 6 months.
- Adolescents: 1 ampoule (1 ml), equivalent to 200,000 IU, every 6 months in winter.
- Pregnancy: ½ ampoule (0.5 ml), equivalent to 100,000 IU, from the 6th or 7th month of pregnancy.
- Elderly: ½ ampoule (0.5 ml), equivalent to 100,000 IU, every 3 months.
- Vitamin D Deficiency:
- 1 ampoule (1 ml), equivalent to 200,000 IU, which can be repeated after 1 to 6 months, or as directed by a registered physician.
- Consult a registered physician for medication advice.
Interactions
Certain medications can lead to Vitamin D3 deficiencies by interfering with its absorption and metabolism. These include magnesium-containing antacids, digoxin, thiazide diuretics, cholestyramine, cholestipol, phenytoin, phenobarbital, orlistat, and mineral oil. Additionally, corticosteroids like prednisolone can increase the demand for Vitamin D3.
Contraindications
Vitamin D3 should not be used in conditions associated with hypercalcemia, in individuals with known hypersensitivity to Vitamin D3 or its excipients, and in cases of established Vitamin D3 toxicity.
Side Effects
While generally well-tolerated, side effects can occasionally include anorexia, fatigue, nausea, vomiting, diarrhea, constipation, weight loss, increased urination, sweating, headaches, thirst, dizziness, and elevated levels of calcium and phosphate in blood and urine.
Pregnancy & Lactation
Research indicates that doses up to 4,000 IU of Vitamin D3 are safe during pregnancy. The recommended daily intake for pregnant women is 400 IU, but those identified as deficient may require higher doses. Pregnant women should consult their healthcare provider for tailored advice, as needs may vary based on individual health conditions.
Vitamin D3 and its metabolites can be excreted in breast milk. While overdose in breastfed infants has not been reported, healthcare practitioners should consider any additional Vitamin D3 supplementation provided to the mother when prescribing for nursing infants.
Precautions & Warnings
Monitor plasma-calcium concentrations periodically in patients receiving high doses of Vitamin D3, those with renal impairment, and during pregnancy and lactation. Individuals taking digoxin and thiazide diuretics should seek advice from a healthcare provider before using Vitamin D3 supplements. Patients with liver or kidney diseases, primary hyperthyroidism, lymphoma, tuberculosis, and granulomatous diseases should also consult a healthcare practitioner before starting Vitamin D3 supplementation.
Use in Special Populations
The safety and efficacy of Vitamin D3 in children under 12 years have not been established.
Overdose Effects
Excessive intake can lead to hypervitaminosis D.
Therapeutic Class
Vitamin D3 is classified as a vitamin essential for bone formation and is included in vitamin D preparations.
Storage Conditions
Store below 30ºC, shielded from light and moisture. Keep out of reach of children.
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