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Vitamin A
Pronunciation
U.S. Brand Names
Generic Available
Synonyms
Pharmacological Index
Use
Pregnancy Risk Factor
Pregnancy/Breast-Feeding Implications
Contraindications
Warnings/Precautions
Adverse Reactions
Overdosage/Toxicology
Drug Interactions
Stability
Mechanism of Action
Pharmacodynamics/Kinetics
Usual Dosage
Reference Range
Dental Health: Local Anesthetic/Vasoconstrictor Precautions
Dental Health: Effects on Dental Treatment
Patient Information
Nursing Implications
Dosage Forms
References

Pronunciation
(VYE ta min aye)

U.S. Brand Names
Aquasol A®; Del-Vi-A®; Palmitate-A® 5000 [OTC]

Generic Available

Yes


Synonyms
Oleovitamin A

Pharmacological Index

Vitamin, Fat Soluble


Use

Treatment and prevention of vitamin A deficiency


Pregnancy Risk Factor

A/X (if dose exceeds RDA recommendation)


Pregnancy/Breast-Feeding Implications

Clinical effect on the fetus: Excessive use of vitamin A shortly before and during pregnancy could be harmful to babies


Contraindications

Hypervitaminosis A, hypersensitivity to vitamin A or any component; pregnancy if dose exceeds RDA recommendations


Warnings/Precautions

Evaluate other sources of vitamin A while receiving this product; patients receiving >25,000 units/day should be closely monitored for toxicity


Adverse Reactions

1% to 10%:

Dermatologic: Drying or cracking of skin

Endocrine & metabolic: Hypercalcemia

Gastrointestinal: Weight loss

Ocular: Visual changes

Miscellaneous: Hypervitaminosis A


Overdosage/Toxicology

Symptoms of acute ingestion of >12,000 international units/kg or chronic overdose (eg, adults: 25,000 units/day for 2-3 weeks) include increased intracranial pressure (headache, altered mental status, blurred vision), bulging fontanelles in infants, jaundice, ascites, cutaneous desquamation; symptoms of acute overdose (12,000 units/kg) include nausea, vomiting, and diarrhea; toxic signs of an overdose commonly respond to drug discontinuation and generally return to normal spontaneously within a few days to weeks.

Treat intracranial hypertension from chronic exposure, if needed; for acute exposure, use gut decontamination and treat symptomatically


Drug Interactions

Decreased effect: Cholestyramine decreases absorption of vitamin A; neomycin and mineral oil may also interfere with vitamin A absorption

Increased toxicity: Retinoids may have additive adverse effects


Stability

Protect from light


Mechanism of Action

Needed for bone development, growth, visual adaptation to darkness, testicular and ovarian function, and as a cofactor in many biochemical processes


Pharmacodynamics/Kinetics

Absorption: Vitamin A in dosages not exceeding physiologic replacement is well absorbed after oral administration; water miscible preparations are absorbed more rapidly than oil preparations; large oral doses, conditions of fat malabsorption, low protein intake, or hepatic or pancreatic disease reduces oral absorption

Distribution: Following oral absorption, large amounts concentrate for storage in the liver; appears in breast milk

Metabolism: Conjugated with glucuronide, undergoes enterohepatic circulation

Elimination: In feces via biliary elimination


Usual Dosage

RDA:

<1 year: 375 mcg

1-3 years: 400 mcg

4-6 years: 500 mcg*

7-10 years: 700 mcg*

>10 years: 800-1000 mcg*

Male: 1000 mcg

Female: 800 mcg

* mcg retinol equivalent (0.3 mcg retinol = 1 unit vitamin A)

Vitamin A supplementation in measles (recommendation of the World Health Organization): Children: Oral: Administer as a single dose; repeat the next day and at 4 weeks for children with ophthalmologic evidence of vitamin A deficiency:

6 months to 1 year: 100,000 units

>1 year: 200,000 units

Note: Use of vitamin A in measles is recommended only for patients 6 months to 2 years of age hospitalized with measles and its complications or patients >6 months of age who have any of the following risk factors and who are not already receiving vitamin A: immunodeficiency, ophthalmologic evidence of vitamin A deficiency including night blindness, Bitot's spots or evidence of xerophthalmia, impaired intestinal absorption, moderate to severe malnutrition including that associated with eating disorders, or recent immigration from areas where high mortality rates from measles have been observed

Note: Monitor patients closely; dosages >25,000 units/kg have been associated with toxicity

Severe deficiency with xerophthalmia: Oral:

Children 1-8 years: 5000-10,000 units/kg/day for 5 days or until recovery occurs

Children >8 years and Adults: 500,000 units/day for 3 days, then 50,000 units/day for 14 days, then 10,000-20,000 units/day for 2 months

Deficiency (without corneal changes): Oral:

Infants <1 year: 100,000 units every 4-6 months

Children 1-8 years: 200,000 units every 4-6 months

Children >8 years and Adults: 100,000 units/day for 3 days then 50,000 units/day for 14 days

Malabsorption syndrome (prophylaxis): Children >8 years and Adults: Oral: 10,000-50,000 units/day of water miscible product

Dietary supplement: Oral:

Infants up to 6 months: 1500 units/day

Children:

6 months to 3 years: 1500-2000 units/day

4-6 years: 2500 units/day

7-10 years: 3300-3500 units/day

Children >10 years and Adults: 4000-5000 units/day


Reference Range

1 RE = 1 retinol equivalent; 1 RE = 1 mg retinol or 6 mg beta-carotene; Normal levels of Vitamin A in serum = 80-300 units/mL


Dental Health: Local Anesthetic/Vasoconstrictor Precautions

No information available to require special precautions


Dental Health: Effects on Dental Treatment

No effects or complications reported


Patient Information

Take exactly as directed; do not take more than the recommended dose. Take with meals. Do not use mineral oil or other vitamin A supplements without consulting prescriber. Report persistent nausea, vomiting, or loss of appetite; excessively dry skin or lips; headache or CNS irritability; loss of hair; or changes in vision.


Nursing Implications

Do not administer by I.V. push; patients receiving >25,000 units/day should be closely monitored for toxicity


Dosage Forms

Capsule: 10,000 units [OTC], 25,000 units, 50,000 units

Drops, oral (water miscible) [OTC]: 5000 units/0.1 mL (30 mL)

Injection: 50,000 units/mL (2 mL)

Tablet [OTC]: 5000 units


References

Braitberg G, Curry SC, and Kunkel DB, "Liver Pathology in Fatal Vitamin A Toxicity," Clin Toxicol, 1995, 33(5):551-2.

Cetaruk EW and Aaron CK, "Hazards of Nonprescription Medications," Emerg Med Clin North Am, 1994, 12(2):483-510.

Committee on Infectious Diseases, "Vitamin A in the Treatment of Measles," Pediatrics, 1993, 91(5):1014-5.

de Francisco A, Chakraborty J, Chowdhury HR, et al, "Acute Toxicity of Vitamin A Given With Vaccines in Infancy," Lancet, 1993, 342(8870):526-7.

DeMaeyer EM, "The WHO Programme of Prevention and Control of Vitamin A Deficiency, Xerophthalmia, and Nutritional Blindness," Nutr Health, 1986, 4(2):105-12.

Hussey GD and Klein M, "A Randomized, Controlled Trial of Vitamin A in Children With Severe Measles," N Engl J Med, 1990, 323(3):160-4.

Kowalski TE, Falestiny M, Furth E, et al, "Vitamin A Hepatotoxicity: A Cautionary Note Regarding 25,000 IU Supplements," Am J Med, 1994, 97(6):523-8.

LaMantia RS and Andrews CE, "Acute Vitamin A Intoxication," South Med J, 1981, 74(8):1012-4.

Nesher G and Zuckner J, "Rheumatologic Complications of Vitamin A and Retinoids," Semin Arthritis Rheum, 1995, 24(4):291-6.

Sanders TA, "Vitamin A and Pregnancy," Lancet, 1990, 336(8727):1375.

White JM, "Vitamin A-Induced Anaemia," Lancet, 1984, 2(8402):573.


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