Indications

Hi-D (Vitamin D3) is indicated for treating and preventing Vitamin D3 deficiency, rickets, osteomalacia, and osteoporosis. It promotes calcium and phosphate absorption for healthy bones and teeth, supports immunity, and helps prevent pre-eclampsia during pregnancy and breastfeeding.

Pharmacology

Calcitriol, the active form of Vitamin D3, binds to Vitamin D receptors throughout the body. Absorbed in the small intestine, Vitamin D3 is metabolized in the liver to Calcidiol and in the kidneys to Calcitriol. Excess Vitamin D3 is stored in fat and muscle tissue with a half-life of about 50 days, and is excreted via feces and urine.

Dosage and Administration

Capsule (Adults): Deficiency treatment is 40000 IU once weekly for 7 weeks. Maintenance dose is 1400-2000 IU daily. Prevention is 20000 IU every 4 weeks. Osteoporosis adjunct is 20000 IU monthly. 
Capsule (Children 12-18 years): Deficiency treatment is 20000 IU every 2 weeks for 6 weeks. Prevention is 20000 IU every 6 weeks. 
Tablets (Film-coated / Chewable): 1000 IU to 2000 IU daily with food or within 1 hour after a meal. 
Oral Solution: Up to 1 year takes 400 IU daily. Ages 1 to 18 take 600 IU daily. 
Injection: Dose varies from 1/2 to 1 ampoule every few weeks or months based on condition, age, or pregnancy status. Oral injection liquid can be mixed with water or milk.

Interactions and Contraindications

Interactions: Phenytoin, barbiturates, glucocorticoids, cholestyramine, and antifungals may lower efficacy. Cardiac glycosides require monitoring due to arrhythmia risk. 
Contraindications: Contraindicated in hypercalcemia, Vitamin D toxicity, and hypersensitivity.

Side Effects and Precautions

Side Effects: Generally well tolerated. Occasional symptoms include hypercalcemia, headache, nausea, abdominal pain, and constipation. 
Precautions: Monitor plasma calcium during high-dose therapy, kidney disease, or pregnancy. Overdose can lead to tissue calcification.

Storage and Class

Therapeutic Class: Bone formation vitamins and Vitamin D preparations. 
Storage: Store below 25°C in a dry place protected from light and out of reach of children.