[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Vitamins](https://durgical.com/en/pharmacology/classes/vitamins/) › Retinol

# Retinol

## Vitamins?

Vitamins

Vitamin A. Prevents night blindness and xerophthalmia, and lowers measles complications in children. High doses in pregnancy cause birth defects.

Updated Nov 1, 2026

Also called: vitamin A

## Quick facts

**Group**
[Vitamins](https://durgical.com/en/pharmacology/classes/vitamins/)

**Target**
Visual pigment of the retina and retinoid receptors in epithelia

**Used for**
Vitamin A deficiency and xerophthalmia

**Key effects**
Usually none at recommended amounts · Dry

**Monitor**
Night vision and the cornea · Signs of excess

**ATC**
A11CA01

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

Retinol is preformed vitamin A. It is needed for vision in dim light, for healthy skin, cornea and mucous membranes, and for the immune response. Deficiency first causes night blindness, then dry conjunctiva and cornea (xerophthalmia) and finally corneal ulceration; it also makes childhood infections such as measles and diarrhoea more severe. Because it is fat-soluble, it builds up in the body, and excess is toxic.

- Retinol supplies the retina's visual pigment
- It keeps cornea, skin and mucous membranes healthy
- It supports the immune response to infection

## Indications

- Vitamin A deficiency and xerophthalmia [Vitamin A deficiency (night blindness and xerophthalmia) →](https://durgical.com/en/conditions/vitamin-a-deficiency/)
- All suspected measles in children under 5 (WHO), to reduce eye damage and deaths [Measles →](https://durgical.com/en/conditions/measles/)
- Supplementation of children aged 6–59 months where vitamin A deficiency is a public health problem

## Adverse effects

### Common

- Usually none at recommended amounts
- Dry, scaly skin with chronic excess

### Serious (rare, important)

- Hypervitaminosis A (acute or chronic poisoning); children are more sensitive
- Birth defects with large doses in pregnancy

## Contraindications

- High doses in pregnancy
- Existing hypervitaminosis A

## Key interactions

**Other vitamin A supplements and multivitamins**
Vitamin A accumulates, so amounts add up toward toxicity

## What is monitored

- Night vision and the cornea in deficiency
- Signs of excess, especially in children and in pregnancy

## Administration and safety

- WHO recommends vitamin A for every child under 5 with suspected measles, given at diagnosis.
- Doses for supplementation programmes and for treatment are kept apart to avoid excess.

## Pregnancy and breastfeeding

Vitamin A is needed in pregnancy, but large doses cause birth defects, so high-dose products are avoided.

## Nursing care

- In a child with measles, check that vitamin A has been given.
- Ask about difficulty seeing in dim light and look at the conjunctiva and cornea.
- Ask women of childbearing age about pregnancy before high doses.
- Count all sources, including multivitamins, to avoid toxicity.

## Pharmacokinetics

**Absorption**
Fat-soluble, absorbed from the gut; found in animal foods

**Distribution**
Stored and accumulates in the body, so excess builds up

## Memory aid

«A for Afternoon light»: the first sign of deficiency is not seeing at dusk (night blindness); the last is a melting cornea.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the earliest sign of vitamin A deficiency?

Night blindness.

## Which children with measles should receive vitamin A according to WHO?

All suspected cases under 5 years of age.

## Why are high-dose vitamin A products avoided in pregnancy?

Large doses cause birth defects.

## What is the world's leading preventable cause of childhood blindness?

Vitamin A deficiency.

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[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 2

- [Measles vaccine](https://durgical.com/en/pharmacology/measles-vaccine/)
- [Colecalciferol](https://durgical.com/en/pharmacology/colecalciferol/)

## Related conditions 2

- [Vitamin A deficiency (night blindness and xerophthalmia)](https://durgical.com/en/conditions/vitamin-a-deficiency/)
- [Measles](https://durgical.com/en/conditions/measles/)

[← Back to the class: Vitamins](https://durgical.com/en/pharmacology/classes/vitamins/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Vitamin A: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/002400.htm) (MedlinePlus (U.S. National Library of Medicine), 2026); [Vitamin A deficiency](https://www.who.int/data/nutrition/nlis/info/vitamin-a-deficiency) (World Health Organization, 2026); [Measles](https://www.who.int/news-room/fact-sheets/detail/measles) (World Health Organization, 2026); [Vitamin A supplementation in infants and children 6–59 months of age](https://www.who.int/tools/elena/interventions/vitamina-children) (World Health Organization (eLENA), 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/retinol/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/retinol/