vitamin A

Dosage

RDA:

• adults & children > 10 years: 5000 IU
• children 7-10 years: 3300-3500 IU
• children 4-6 years: 2500 IU
• children 6 months-3 years: 1500-2000 IU
• infants up to 6 months: 1500 IU

1 mg = 3333 units severe deficiency:

• 100,000 IU/day for 3 days
• followed by 50,000 IU daily for 2 weeks
• then 10,000-20,000 IU daily for 2 months

Capsule: 25,000 units, 50,000 units

Pharmacokinetics

• retinyl esters are storage forms of vitamin A

Adverse effects

• not common (1-10%)
  • irritability, vertigo, lethargy, malaise, fever, headache, drying or cracking of skin, hypercalcemia, weight loss, visual changes, hypervitaminosis
• fracture
  • 2-fold increase risk of fractures in postmenopausal women not taking hormone replacement therapy with high intake of vitamin A
  • high serum levels of retinol (but not beta-carotene) associated with 1.6 fold increased risk of fracture in 50-75 year old men

Drug interactions

• carbamazepine: increased clearance of carbamazepine
• cholestyramine, mineral oil: decreased absorption of vit A
• oral contraceptives: increased absorption of vit A
• isotretinoin, etretinate: increased toxicity
• vitamin A can antagonize the ability of vitamin D to enhance Ca+2 absorption

More general terms

• vitamin

More specific terms

• alpha-carotene
• beta-carotene
• retinol; vitamin A1

Additional terms

• vitamin A deficiency (hyporetinemia)

Component of

• vitamin a/vitamin e
• kelp/vitamin a
• ergocalciferol/vitamin a
• cholecalciferol/vitamin a
• ascorbate/cobalamin/folic acid/nicotinic acid/pyridoxine/riboflavin/sodium fluoride/thiamine/vitamin a/vitamin d/vitamin e
• ascorbate/cholecalciferol/ferrous sulfate/sodium fluoride/vitamin a
• ascorbate/cholecalciferol/cobalamin/nicotinic acid/pyridoxine/riboflavin/sodium fluoride/thiamine/vitamin a/vitamin e
• ascorbate/cholecalciferol/cobalamin/folic acid/magnesium oxide/nicotinic acid/polysaccharide iron complex/potassium iodide/pyridoxine/riboflavin/thiamine/vitamin a/vitamin e/zinc oxide
• ascorbate/cholecalciferol/cobalamin/copper sulfate/ferrous fumarate/folic acid/kelp/magnesium oxide/magnesium sulfate/nicotinamide/pyridoxine/riboflavin/vitamin a/zinc sulfate
• ascorbate/biotin/calcium carbonate/cobalamin/ferrous fumarate/folic acid/magnesium oxide/nicotinamide/pantothenate/pyridoxine/riboflavin/thiamine/vitamin a/vitamin e/zinc oxide
• ascorbate/biotin/calcium carbonate/cobalamin/ferrous fumarate/folic acid/magnesium oxide/nicotinamide/pantothenate/pyridoxine/riboflavin/thiamine/vitamin a/vitamin e/zinc/zinc oxide
• alpha tocopheryl acetate/ascorbate/cholecalciferol/cobalamin/nicotinamide/pyridoxine/riboflavin/thiamine/vitamin a
• alpha tocopherol/ascorbate/biotin/cholecalciferol/cobalamin/folic acid/nicotinamide/panthenol/pyridoxine/riboflavin/thiamine/vitamin a/vitamin k
• alpha tocopherol/ascorbate/biotin/biotin/cobalamin/ergocalciferol/folic acid/multivitamin/nicotinamide/panthenol/pyridoxine/riboflavin/thiamine/vitamin a/vitamin k
• ascorbate/cholecalciferol/sodium fluoride/vitamin a
• vitamin a/vitamin d
• ascorbate/vitamin a/vitamin d
• ascorbate/cobalamin/nicotinic acid/pyridoxine/riboflavin/thiamine/vitamin a/vitamin d/vitamin e
• ascorbate/ferrous sulfate/vitamin A/vitamin D
• ascorbate/ferrous sulfate/vitamin A
• ascorbate/ferrous sulfate/nicotinic acid/pyridoxine/riboflavin/thiamine/vitamin a/vitamin d/vitamin e