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vitamin A

Medically Reviewed on 3/24/2022

Generic Name: vitamin A

Brand and Other Names: Retinol, Aquasol A, retinyl acetate, retinyl palmitate

Drug Class: Vitamins, Fat-Soluble

What is vitamin A, and what is it used for?

Vitamin A is a micronutrient that has many functions in the body and is essential for good health. Vitamin A is fat-soluble and is naturally present in many foods.

Vitamin A is used as a dietary supplement to compensate for natural deficiency and to treat dry eyes (xerophthalmia). Vitamin A deficiency is a common cause for night blindness. When used topically as a retinoid (Retinol), it is used to treat acne.

Vitamin A has several important functions:

  • Essential for normal eye function and the maintenance of eye integrity; helps prevent dryness in the eye and enables visual adaptation to darkness
  • Development and maintenance of epithelial tissue, the outermost protective layer on all internal and external body surfaces
  • Helps bone development
  • Plays a role in functional capacity of reproductive organs
  • Strengthens the immune function
  • Important for development of normal teeth and hair
  • Crucial for normal fetal development

Two forms of vitamin A occur as natural dietary sources:

  • Preformed vitamin A: Present in meat, fish, poultry and dairy products
  • Provitamin A: Present in fruits, vegetables and plant-based products

Vitamin A dietary supplements are available over-the-counter in either form of vitamin A, or a combination of the two. Vitamin A absorption requires adequate absorption of fats, because it is not soluble in water. Excessive Vitamin A intake from supplements can lead to vitamin A toxicity, while intake from foods usually does not.

Uses of vitamin A include:

  • Vitamin A deficiency
  • Xerophthalmia

Vitamin A is also being studied (orphan designation) for use in:

  • Bronchopulmonary dysplasia, a lung condition that develops in newborns, often in premature babies after receiving supplemental oxygen
  • Retinopathy of prematurity, a disorder of the retina in premature babies

Warnings

  • Do not take vitamin A supplements if you are hypersensitive to it or any of its components
  • Do not take if your vitamin A levels are normal or high (hypervitaminosis A)
  • Do not administer vitamin A as intravenous (IV) injections
  • Individuals whose intestinal ability to absorb nutrients is impaired (malabsorption syndrome), should receive vitamin A as intramuscular (IM) injections, not orally
  • Use with caution in patients with renal impairment

What are the side effects of vitamin A?

Side effects of vitamin A may include:

Chronic vitamin A toxicity (hypervitaminosis A) from chronic high doses can cause:

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug.

Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

QUESTION

Acne is the result of an allergy. See Answer

What are the dosages of vitamin A?

Capsule

  • 7,500 U
  • 8,000 U
  • 10,000 U
  • 25,000 U

Injectable solution

  • 50,000 U/ml

Tablet

  • 10,000 U
  • 15,000 U

Adults:

Recommended Daily Allowance (RDA)

Described as retinol activity equivalent (RAE)

1 RAE = Retinol 1 mcg

Males:

  • 900 mcg per day (3,000 units per day)

Females:

  • 700 mcg per day (2330 units per day)
  • Older than 18 years pregnant: 750-770 mcg per day (2,500-2,600 units per day)
  • Older than 18 years breastfeeding: 1300 mcg RAE (4330 units per day)

Upper Intake Levels

  • Older than 18 years: 3,000 mcg per day RAE (10,000 units per day)
  • During pregnancy: 3,000 mcg per day RAE (10,000 units per day)
  • Lactation: 3,000 mcg per day RAE (10,000 units per day)

Vitamin A Deficiency

  • Malabsorption or oral administration not feasible: 100,000 units per day injected intramuscularly for 3 days; then 50,000 units per day for 2 weeks, to be followed with oral therapy
  • Oral therapy: take an oral therapeutic multivitamin containing 10,000-20,000 units per day of vitamin A for 2 months
  • Deficiency prophylaxis: 10,000-50,000 units orally once per day

Xerophthalmia (off label)

  • Recommended dose except for females of reproductive age: 200,000 units orally once daily for 2 days. Repeat dose again after 2 weeks
  • Females of reproductive age with night blindness or Bitot's spots: 5,000-10,000 units per day; 10,000 units per day maximum of 25,000 units once weekly for no more than 4 weeks

Pediatrics:

Recommended Daily Allowance (RDA)

  • Infants 0-6 months: 400 mcg/day RAE (1,333 units per day)
  • Infants 6-12 months: 500 mcg/day RAE (1,666 units per day)
  • Children 1-3 years: 300 mcg/day RAE (1,000 units per day)
  • Children 3-8 years: 400 mcg/day RAE (1,333 units per day)
  • Children 8-13 years: 600 mcg/day RAE (2,000 units per day)
  • Children 13-18 years: 900 mcg/day RAE (3,000 units per day)

Upper Intake Levels

  • Children 0-3 years: 600 mcg per day RAE (2,000 units per day)
  • Children 3-8 years: 900 mcg per day RAE (3,000 units per day)
  • Children 8-13 years: 1,700 mcg per day RAE (5,667 units per day)
  • Children 13-18 years, pregnant: 2,800 mcg per day RAE (9,333 units per day)
  • Children 13-18 years, breastfeeding: 2,800 mcg per day RAE (9,333 units per day)

Vitamin A Deficiency

  • Use intramuscular route when oral administration is not possible or in malabsorption syndrome
  • Infants: 7,500-15,000 units per day for 15 days
  • Children 1-8 years: 17,500-35,000 units per day for 10 days
  • Children 8 years and older:
    • Malabsorption or oral administration not feasible: 100,000 units per day, intramuscular for 3 days, then 50,000 units per day for 2 weeks; follow with oral therapy
    • Oral therapy: take an oral therapeutic multivitamin containing 10,000-20,000 units of daily vitamin A for 2 months
    • Deficiency prophylaxis: 10,000-50,000 units orally once per day

Xerophthalmia

  • Infants under 6 months: 50,000 units once per day for 2 days, repeat once with single-dose after 2 weeks
  • Infants 6-12 months: 100,000 units once per day for 2 days, repeat with single-dose after 2 weeks
  • Children over 12 months, except females of reproductive age: 200,000 units once per day for 2 days, repeat with a single dose after 2 weeks
  • Females of reproductive age with night blindness or Bitot's spots: 5,000-10,000 units per day, 10,000 units per day with a maximum of 25,000 units once weekly for no more than 4 weeks

Overdose

What drugs interact with vitamin A?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

  • Vitamin A has no known severe interactions with other drugs.
  • Serious interactions of vitamin A include:
    • pexidartinib
    • pretomanid
  • Moderate Interactions of vitamin A include:
  • Vitamin A has minor interactions with at least 45 different drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

Pregnancy and breastfeeding

  • Vitamin A is a micronutrient essential for the health of pregnant women and normal development of the fetus. Vitamin A requirements are greater in pregnant women, and supplemental vitamin A intake during pregnancy is acceptable.
  • Vitamin A intake during pregnancy, however, should not exceed the daily recommended dose; excessive vitamin A levels, particularly during the first quarter of pregnancy can cause fetal harm or spontaneous abortion.
  • Vitamin A is present in breast milk and is a beneficial nutrient to the breastfeeding baby; must not exceed daily recommended dose.

What else should I know about vitamin A?

  • The best way to meet daily requirements of vitamin A is to eat/drink foods rich in vitamin A.
  • Do not exceed the daily recommended dose if you take vitamin A supplement.
  • Vitamin A is marketed as a dietary supplement and does not require extensive pre-marketing approval from the FDA; use with caution.

Summary

Vitamin A is a micronutrient used as a dietary supplement to compensate for natural deficiency and to treat dry eyes (xerophthalmia). When used topically as a retinoid (Retinol), it is used to treat acne. Side effects of vitamin A may include dry mucus, opacity of the cornea, inflammation of the membrane in the eye whites and inner surface of eyelids (conjunctivitis), facial dermatitis, lip inflammation (cheilitis), inflammatory lesions (granulomas) in acne, and others. Acute overdose of vitamin A can cause nausea, dizziness, fatigue, headaches, skin peeling, liver failure and coma that can lead to death. Never exceed the daily recommended dose of vitamin A, especially if pregnant.

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Medically Reviewed on 3/24/2022
References
https://www.rxlist.com/consumer_vitamin_a_retinol/drugs-condition.htm

https://reference.medscape.com/drug/retinol-aquasol-a-vitamina-344426#6

https://ods.od.nih.gov/factsheets/VitaminA-Consumer/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6470929/