Ascorbic Acid

Pronunciation
( Vitamin C )

Pronunciation: as-KORE-bik AS-id
Class: Vitamin

Trade Names

Acreola C
- Wafer 500 mg

Ascor L 500
- Injection 500 mg/mL

Protexin
- Syrup 500 mg/15 mL

Vitamin C
- Capsules 500 mg
- Capsules, ER 500 mg
- Liquid 500mg/5 mL
- Lozenge 60 mg
- Tablets 100 mg
- Tablets 250 mg
- Tablets 500 mg
- Tablets 1,000 mg
- Tablets, ER 500 mg
- Tablets, ER 1,000 mg
- Tablets, ER 1,500 mg
- Tablets, chewable 100 mg vitamin C
- Tablets, chewable 250 mg vitamin C
- Tablets, chewable 300 mg vitamin C
- Tablets, chewable 500 mg vitamin C
- Tablets, chewable 1,000 mg vitamin C

Vita-C
- Crystals, oral 1,000 mg per ¼ tsp

Proflavanol (Canada)
Revitalose-C-1000 (Canada)
Timedose Vitamin C (Canada)

Pharmacology

Essential vitamin believed to be important for synthesis of cellular components, catecholamines, steroids, and carnitine.

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Pharmacokinetics

Absorption

Absorbed almost completely from distal small intestine.

Distribution

Distributed throughout water-soluble compartments. Adrenal cortex, leukocytes, platelets, and pituitary gland contain high concentrations.

Elimination

Excreted in the urine.

Indications and Usage

Prevention and treatment of ascorbic acid deficiency.

Unlabeled Uses

Treatment of idiopathic methemoglobinemia; combination therapy with methenamine to increase acidity of urine. Although not proven scientifically, prevention of common colds and treatment of cancer, asthma, atherosclerosis, burns, and other wounds. Topical vitamin C may photoprotect against UV radiation because of its antioxidant and anti-inflammatory properties.

Contraindications

Hypersensitivity to any component of the product.

Dosage and Administration

Recommended Daily Allowances
19 y of age and older Men

90 mg/day.

Women

75 mg/day.

Pregnant

85 mg/day.

Breast-feeding

120 mg/day

14 to 18 y of age Male adolescents

75 mg/day.

Female adolescents

65 mg/day.

Pregnant

80 mg/day.

Breast-feeding

115 mg/day.

9 to 13 y of age

45 mg/day.

4 to 8 y of age

25 mg/day.

1 to 3 y of age

15 mg/day.

30 days to 1 y of age

6 mg/kg/day.

Nicotine use Adults

The RDA for smokers is 100 mg/day because of an increased utilization of vitamin C.

Deficiency

IV/IM/subcutaneous 100 to 250 mg once or twice daily. If deficiency is severe, give 1 to 2 g/day. Up to 6 g/day has been administered without toxicity. In other conditions in which the need is increased, 3 to 5 times the RDA appears to be adequate.

Burns

IV/IM/subcutaneous 200 to 500 mg/day. For severe burns, give 1 to 2 g/day.

Surgery

IV/IM/subcutaneous 300 to 500 mg/day for 7 to 10 days, both pre- and postoperatively to enhance wound healing. 1 to 2 g/day for 4 to 7 days preoperatively has been used in gastrectomy patients.

General Advice

  • Parenteral dosing used in acute deficiency or when oral absorption is uncertain.
  • Avoid rapid IV administration.
  • For IV injection, dilute into a large volume parenteral, such as normal saline or glucose, to minimize adverse reactions associated with IV injection.
  • Taper vitamin C prior to discontinuing supplementation.
  • Pressure may develop in vial or ampule upon storage; exercise caution and relieve pressure by inserting a sterile, empty syringe into vial. Take precautions to wrap the ampule in a protective covering while it is being opened.

Storage/Stability

Store injection in refrigerator at 36° to 46°F. Do not allow to stand at room temperature before use. Store oral products at room temperature.

Drug Interactions

Amygdalin

Risk of life-threatening cyanide toxicity to amygdalin may be increased. Although the FDA has banned the use of the synthetic form of amygdalin, laetrile, for cancer treatment, amygdalin has been used as alternative medicine by some patients. Avoid concurrent use.

Disulfiram

On occasion, ascorbic acid has been used as a specific antidote for symptoms resulting from the interaction between ethanol and disulfiram; it may be expected that the coadministration of ascorbic acid will interfere with the effectiveness of disulfiram given to patients to encourage abstention from alcohol.

Drugs affected by urinary acidification (eg, amphetamine, mexiletine)

Acidification of the urine by ascorbic acid may cause precipitation of cysteine, urate, or oxalate stones and will alter the excretion of certain other drugs administered concurrently. Elimination of certain drugs may be enhanced by urinary acidification. Monitor the clinical response of the patient. If an interaction is suspected, it may be necessary to discontinue ascorbic acid or adjust the dose of the drug altered by urinary acidification.

Warfarin

Large ascorbic acid doses interfere with the anticoagulant effect of warfarin. Monitor coagulation parameters in patients receiving ascorbic acid 5 g or more daily and adjust the warfarin dose as needed.

Laboratory Test Interactions

Because ascorbic acid is a strong reducing agent, it interferes with numerous laboratory tests based on oxidation-reduction reactions. Diabetic patients taking more than 500 mg/day of ascorbic acid may obtain false readings of their urinary glucose test. No exogenous ascorbic acid should be ingested for 48 to 72 hours before amine-dependent stool occult blood tests are conducted because false negative results may occur.

Adverse Reactions

CNS

Faintness or dizziness may occur with rapid IV administration.

GI

Diarrhea, nausea, vomiting.

Genitourinary

Excessive doses over a long period of time may cause precipitation of cystine, oxalate, or urate crystals in kidney.

Miscellaneous

Injection-site irritation may occur with IM or subcutaneous administration.

Precautions

Pregnancy

Category C (in doses exceeding the RDA); Category A (in doses up to RDA).

Lactation

Excreted in breast milk.

Tartrazine Sensitivity

Some injectable products contain tartrazine, which can precipitate breathing difficulties in sensitive individuals.

Sulfite Sensitivity

Some injectable products contain sulfites, which may precipitate a reaction in sensitive individuals.

Aluminum toxicity

Some injectable products contain aluminum, which may lead to CNS and bone toxicity.

Excessive doses

Diabetic patients, patients prone to renal calculi, patients on sodium-restricted diets, and those taking anticoagulants should not take excessive doses (more than 5 g/day) over extended periods of time.

Patient Information

  • Explain that taking this product with foods high in iron will enhance absorption of iron.
  • Explain to any patient scheduled for glucose studies that product should not be taken for at least 48 to 72 h before test.
  • Inform patient that abruptly stopping high-dose therapy may lead to loosening of teeth and bleeding gums.

Copyright © 2009 Wolters Kluwer Health.

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