Vitamin A deficiency-related conditions in ophthalmology such as night blindness, xerophthalmia, and dermatological disorders including changes in skin, hair, and nails. It is used as supportive therapy for mucosal illnesses such as sinusitis and bronchitis, and in skin conditions including acne vulgaris, ichthyosis, Darier's disease, and psoriasis. It also helps fulfill increased vitamin A demand during growth, improves resistance against infections, and prevents night blindness. Additionally, it is indicated for vitamin A deficiency following diarrhoea and for measles prophylaxis.
Vitamin A
Generic MedicinePharmacology
Beta-carotene, retinol, and retinal possess effective vitamin A activity. Retinal and retinol remain in chemical equilibrium within the body and exhibit equivalent antixerophthalmic effects. Retinal combines with the rod pigment opsin in the retina to form rhodopsin, which is essential for visual dark adaptation.
Vitamin A supports normal growth and maintains the integrity of epithelial cells. A healthy adult liver can generally store enough vitamin A to meet the body's needs for up to two years. Vitamin A is readily absorbed from the gastrointestinal tract, where beta-carotene is converted into vitamin A. Its absorption depends on bile salts, pancreatic lipase, and dietary fat. It is transported through the bloodstream to the liver via chylomicrons. In the liver, vitamin A is mainly stored as palmitate. Normal serum vitamin A levels range from 80–300 Units per 100 mL, while carotenoid levels range from 270–753 Units per 100 mL. The normal adult liver contains approximately 100 to 300 micrograms of vitamin A per gram, primarily in the form of retinol palmitate.
Dosage Administration
For Adults: 50000 IU-100000 IU daily up to 200000 IU if necessary.
Children (Above 1 year):
- Night blindness, Bitot's spots, Xerophthalmia: 200000 IU 1st day, 2nd day, 14th day
- Measles: 200000 IU 1st day, 2nd day
- Diarrhoea, Respiratory tract infection: 200000 IU every time after disease
- Severe malnutrition: 200000 IU single-dose or as directed by the registered physician.
Contraindications
Hypervitaminosis A and hypersensitivity to any component of this formulation are contraindications to the use of Vitamin A.
Side Effects
Vitamin A toxicity may cause irritability, vomiting, decreased appetite, headache, dry and itchy skin, skin peeling, fatigue, pain in the ankles and feet, muscle pain, hair loss, papilledema, nystagmus, liver sclerosis, and cirrhosis.
Pregnancy & Lactation
The safety of taking more than 6,000 Units of vitamin A daily during pregnancy has not been established. Excessive intake beyond the recommended dietary allowance may cause fetal harm in pregnant women. Animal studies have demonstrated fetal abnormalities associated with overdose in multiple species. Reported abnormalities include malformations of the central nervous system, eyes, palate, and urogenital tract. Therefore, vitamin A intake exceeding the recommended dietary allowance is contraindicated in women who are or may become pregnant. If vitamin A is used during pregnancy, or if pregnancy occurs while taking vitamin A, the patient should be informed about the potential risks to the fetus.
The U.S. Recommended Daily Allowance (RDA) of vitamin A (5,000 Units) is considered appropriate for nursing mothers.
Precautions & Warnings
A vitamin A-free interval should be maintained after long-term therapy with vitamin A. During pregnancy, daily doses above 5,000 IU should be avoided. Doses exceeding 50,000 IU should only be taken under medical supervision.
Therapeutic Class
Vitamin-A preparations
Storage Conditions
Store below 25°C temperature, protected from light and moisture. Keep out of the reach of children.
Common Questions
What is Vitamin A for?
What does Vitamin A do?
What are the side effects of Vitamin A?
What happens if you take too much Vitamin A?
Can Vitamin A be taken during pregnancy?