The following amounts have been found to be toxic orally. Toxicity manifestations depend on the age, dosage, size, and duration of administration.
Acute toxicity — single dose (25,000 Units/kg body weight)
- Infant: 350,000 Units
- Adult: Over 2 million Units
Chronic toxicity (4,000 Units/kg body weight for 6 to 15 months)
- Infants 3 to 6 months old: 18,500 Units (water dispersed)/day for 1 to 3 months.
- Adult: 1 million Units daily for three days; 50,000 Units daily for longer than 18 months; 500,000 Units daily for two months.
Hypervitaminosis A Syndrome:
General manifestations: Fatigue, malaise, lethargy, abdominal discomfort, anorexia, and vomiting.
- Specific manifestations:
- Skeletal: hepatotoxicity, hard tender cortical thickening over the radius and tibia, migratory arthralgia, slow growth, and premature closure of the epiphysis leading to arrested bone growth in children.
- Central Nervous System: irritability, headache, and increased intracranial pressure as manifested by bulging fontanels, papilledema, and exophthalmos.
- Dermatologic: fissures of the lips, drying and cracking of the skin, alopecia, scaling, massive desquamation, and increased pigmentation.
- Systemic: hypomenorrhea, hepatosplenomegaly, hepatotoxicity, jaundice, leukopenia, vitamin A plasma level over 1,200 Units/100 mL.
The treatment of hypervitaminosis A consists of immediate withdrawal of the vitamin along with symptomatic and supportive treatment.
The intravenous administration. Hypervitaminosis A. Sensitivity to any of the ingredients in this preparation.
Use in Pregnancy
Safety of amounts exceeding 6,000 Units of vitamin A daily during pregnancy has not been established at this time. The use of vitamin A in excess of the recommended dietary allowance may cause fetal harm when administered to a pregnant woman. Animal reproduction studies have shown fetal abnormalities associated with overdosage in several species. Malformations of the central nervous system, the eye, the palate, and the urogenital tract are recorded. Vitamin A in excess of the recommended dietary allowance is contraindicatedin women who are or may become pregnant. If vitamin A is used during pregnancy, or if the patient becomes pregnant while taking vitamin A, the patient should be apprised of the potential hazard to the fetus.