ascorbic acid

Contraindicated in:

Tartrazine hypersensitivity (some oral products contain tartrazine—FDC yellow dye #5).

Use Cautiously in:

Renal impairment (↑ risk of nephrolithiasis);
Recurrent kidney stones (↑ risk of nephrolithiasis);
Glucose 6–phosphate dehydrogenase (G6PD) deficiency (↑ risk for hemolysis; avoid exceeding US recommended daily allowance);
Lactation: Use while breastfeeding only if potential maternal benefits justifies potential risk to infant;
Pedi: Children <2 yr (↑ risk of nephrolithiasis); children <5 mo (safety and effectiveness of IV formulation not established)
Geri: ↑risk of nephrolithiasis in older adults.

Adv. Reactions/Side Effects ⬆ ⬇

Derm: flushing

GI: cramps, diarrhea, heartburn, nausea, vomiting

GU: nephrolithiasis, oxalate nephropathy

Hemat: hemolysis (in G6PD deficiency)

Local: pain at injection site

Neuro: fatigue, drowsiness, headache, insomnia

Interactions ⬆ ⬇

Drug-drug:

If urinary acidification occurs, may ↑ excretion and ↓ effectiveness of mexiletine,amphetamine, fluphenazine, or tricyclic antidepressants.
Large doses (>10 g/day) may ↓ effectiveness of warfarin.
↑iron toxicity when given concurrently with deferoxamine.
May ↓ effectiveness of erythromycin, streptomycin, doxycycline, and bleomycin.

Availability ⬆ ⬇

(Generic available)

Tablets: 100 mg^OTC; 250 mg^OTC; 500 mg^OTC; 1 g^OTC
Chewable tablets: 100 mg^OTC; 125 mg^OTC; 250 mg^OTC; 500 mg^OTC
Extended-release capsules: 500 mg^OTC
Extended-release tablets: 500 mg^OTC; 1.5 g^OTC
Oral solution: 100 mg/mL^OTC
Solution for injection: 250 mg/mL; 500 mg/mL
In combination with:
other vitamins and minerals in multivitamin preparations.

Route/Dosage ⬆ ⬇

Ascorbic Acid Deficiency

IV (Adults ): 70–150 mg once daily; doses up to 3 g/day may be necessary for conditions with ↑ requirements

Nutritional Supplementation

PO (Adults ): 100 to 1,500 mg once daily.

Parenteral Nutrition (Maintenance Requirement)

IV (Adults ): 100 to 200 mg/day.
IV (Children ): 80 mg/day.
IV (Infants ): 15–25 mg/kg/day (max = 80 mg/day).

Scurvy

PO (Adults ): 100–300 mg once daily until body stores are replenished
IV (Adults and Children ≥11 yr): Ascor:200 mg once daily for up to 7 days. If no improvement after 1 wk of treatment, retreat until symptoms resolve.
IV (Children 1–<11 yr): Ascor:100 mg once daily for up to 7 days. If no improvement after 1 wk of treatment, retreat until symptoms resolve.
IV (Children 5 mo-<1 yr): Ascor:50 mg once daily for up to 7 days. If no improvement after 1 wk of treatment, retreat until symptoms resolve.

US Brand Names ⬆ ⬇

Action ⬆ ⬇

Necessary for collagen formation and tissue repair.
Involved in oxidation reduction reactions; tyrosine, folic acid, iron, and carbohydrate metabolism; lipid and protein synthesis; cellular respiration; and resistance to infection.

Therapeutic effects:

Replacement in deficiency states.
Supplementation during increased requirements.

Classifications ⬆ ⬇

Therapeutic Classification: vitamins

Pharmacologic Classification: water soluble vitamins

Pharmacokinetics ⬆ ⬇

Absorption: Actively absorbed after oral administration by a saturable process. IV administration results in complete bioavailability.

Distribution: Widely distributed to tissues.

Metabolism/Excretion: Converted to compounds that are excreted by the kidneys.

Half-Life: 7.4 hr.

Time/Action Profile ⬆ ⬇

(response to skeletal and hemorrhagic changes in scurvy)

ROUTE	ONSET	PEAK	DURATION
PO, IV	2 days–3 wk	unknown	unknown

Patient/Family Teaching ⬆ ⬇

Explain the purpose and side effects of ascorbic acid. Advise patient to take as directed and not to exceed dose prescribed. Excess doses may lead to diarrhea and urinary stone formation. If a dose is missed, skip dose and return to dose schedule.
Vitamin C Deficiency: Encourage patient to comply with diet recommendations of health care professional. Explain that the best source of vitamins is a well-balanced diet.
- Foods high in ascorbic acid include citrus fruits, tomatoes, strawberries, cantaloupe, and raw peppers. Gradual loss of ascorbic acid occurs when fresh food is stored, but not when it is frozen. Rapid loss is caused by drying, salting, and cooking.
- Patients self-medicating with vitamin supplements should be cautioned not to exceed RDA. The effectiveness of megadoses of vitamins for treatment of various medical conditions is unproven and may cause side effects. Abrupt withdrawal of megadoses of ascorbic acid may cause rebound deficiency.
Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
Rep: Advise women of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding. Advise the patient to follow the US Recommended Dietary Allowance for women who are pregnant or lactating when treatment for scurvy is being considered.

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Indications ⬇

Contraind./Precautions ⬆ ⬇