Drug reference

retinol

Fat-soluble vitamin · Vitamin supplement

Fat-soluble vitaminVitamin supplementATC A11CA01

CDSCO approvedATC A11CA01

EXCRETION

—

not curated

INTERACTIONS

—

none in our sources

PREGNANCY

—

not curated

Mechanism

Retinal, generated by reversible oxidation of retinol, is a component of the light-sensitive pigments Rhodopsin and Iodopsin, essential for vision. Vitamin A promotes the differentiation and maintains the structural integrity of epithelia, encourages mucus secretion, inhibits keratinization, and improves resistance to infection. It is also required for bone growth, spermatogenesis, foetal development, and proper immune response.

Indications

Prophylaxis of vitamin A deficiency (during infancy, pregnancy, lactation, hepatobiliary diseases, steatorrhoea)Treatment of established vitamin A deficiency

Dosing

Adult: Prophylaxis: 3000–5000 IU/day. Treatment of established deficiency: 50,000–100,000 IU i.m or orally for 1–3 days, followed by intermittent supplemental doses.
Pediatric: Prophylaxis in infants: 3000–5000 IU/day.
Max dose: Daily intake should not exceed 20,000 IU.

Pharmacokinetics

Protein binding

Free retinol released by hepatocytes combines with retinol binding protein (RBP a plasma globulin) and is transported to the target cells. On entering them, it gets bound to the cellular retinol binding protein (CRBP). Small amount is conjugated with glucuronic acid.

Metabolism

Retinyl palmitate is hydrolysed in intestines to retinol, which is reesterified and stored in liver cells. Free retinol combines with retinol binding protein (RBP) for transport. β-carotene is split into retinal, half of which is reduced to retinol. Small amounts are conjugated with glucuronic acid.