Ascorbic Acid Drug Information

Ascorbic acid injection is indicated for the short term (up to 1 week) treatment of scurvy in adult and pediatric patients, age 5 months and older, for whom oral administration is not possible, insufficient or contraindicated. Limitations of Use Ascorbic acid injection is not indicated for the treatment of vitamin C deficiency that is not associated with signs and symptoms of scurvy.

Important Preparation and Administration Instructions •

Ascorbic acid injection vials contain 25,000 mg of ascorbic acid and the largest recommended single dose is 200 mg. Do not give the entire contents of the vial to a single patient. • Do not administer ascorbic acid injection as an undiluted intravenous injection. • Minimize exposure to light because ascorbic acid injection is light sensitive. • Ascorbic acid injection is supplied as a Pharmacy Bulk Package (PBP) which is intended for dispensing of single doses to multiple patients in a pharmacy admixture program and is restricted to the preparation of admixtures for infusion: a. Use only in a suitable ISO Class 5 work area such as a laminar flow hood (or an equivalent clean air compounding area). b.

Penetrate each PBP vial closure only one time with a suitable sterile transfer device or dispensing set that allows measured dispensing of the contents. Given that pressure may develop within the vial during storage, exercise caution when withdrawing contents from the vial. c. Once the closure system has been penetrated, complete all dispensing from the PBP vial within 4 hours.

Each dose must be used immediately. Discard unused portion. d. Prior to administration, ascorbic acid injection must be diluted in a suitable infusion solution and the final solution for infusion must be isotonic (undiluted the osmolarity of ascorbic acid injection is approximately 5,900 mOsmol/L).

Prior to preparing the admixture for infusion, calculate the osmolarity of the intended admixture for infusion. Add one daily dose of ascorbic acid injection directly to an appropriate volume of a suitable infusion solution (e.g., 5% Dextrose Injection, Sterile Water for Injection) and add appropriate solutes, as necessary, to make the final solution isotonic. Sterile Water for Injection is highly hypotonic; adjust solute content, as necessary, to make the final infusion solution isotonic prior to injection.

Do not mix ascorbic acid injection with solutions containing elemental compounds that can be reduced (e.g., copper). The concentration of ascorbic acid in the final, admixture solution for infusion is to be in the range of 1 to 25 mg of ascorbic acid per mL. For example, for the largest recommended dose: Add 200 mg of ascorbic acid (equivalent to 0.4 mL of ascorbic acid injection) to 7.5 mL of Sterile Water for Injection to produce an infusion solution having an approximate osmolarity of 290 mOsmol/L.

In this specific example, addition of solute is NOT necessary because the solution is isotonic. e. Prepare the recommended dose based on the patient population. f. Visually inspect for particulate matter and discoloration prior to administration (the diluted ascorbic acid injection solution should appear colorless to pale yellow). g.

Immediately administer the admixture for infusion as a slow intravenous infusion

Recommended Dosage Table 1 provides recommended doses of ascorbic acid injection based on patient population and infusion rates of diluted ascorbic acid injection solution. Table 1: Recommended Dose of ascorbic acid injection and Infusion Rate of Diluted ascorbic acid injection Solution The recommended maximum duration of daily treatment with ascorbic acid injection is seven days. If no improvement in scorbutic symptoms is observed after one week of treatment, retreat until resolution of scorbutic symptoms is observed.

Repeat dosing is not recommended in pediatric patients less than 11 years of age.

Dosage Reductions in Specific Populations Women who are pregnant or lactating and patients with glucose-6-dehydrogenase deficiency should not exceed the U.S. Recommended Dietary Allowance (RDA) or daily Adequate Intake (AI) level for ascorbic acid for their age group and condition.

• The following adverse reactions are discussed in greater detail in other sections of the labeling:
• Oxalate nephropathy and Nephrolithiasis.
• Hemolysis in patients with glucose-6-phosphate dehydrogenase deficiency. The following adverse reactions associated with the use of ascorbic acid were identified in the literature. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to estimate their frequency reliably or to establish a causal relationship to drug exposure: Administration site reactions: pain and swelling. Ascorbic acid injection should not be rapidly administered. Acute and chronic oxalate nephropathy have occurred with prolonged administration of high doses of ascorbic acid. In patients with glucose-6-phosphate dehydrogenase deficiency, severe hemolysis has occurred. Most common adverse reactions are pain and swelling at the site of infusion To report SUSPECTED ADVERSE REACTIONS, contact or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Antibiotics

Ascorbic acid may decrease activities of erythromycin, kanamycin, streptomycin, doxycycline, and lincomycin. Bleomycin is inactivated in vitro by ascorbic acid. If the antibiotic efficacy is suspected to be decreased by concomitant administration of ascorbic acid injection, discontinue ascorbic acid injection administration.

Amphetamines & Other Drugs Affected by Urine Acidification

Ascorbic acid may acidify the urine and lower serum concentrations of amphetamine by increasing renal excretion (as reflected by changes in amphetamine urine recovery rates). In case of decreased amphetamine efficacy, discontinue ascorbic acid injection administration. Standard monitoring of therapy is warranted.

In addition, acidification of urine by ascorbic acid will alter the excretion of certain drugs affected by the pH of the urine (e.g., fluphenazine) when administered concurrently. It has been reported that concurrent administration of ascorbic acid and fluphenazine has resulted in decreased fluphenazine plasma concentrations.

Warfarin

Limited case reports have suggested interference of ascorbic acid with the anticoagulation effects of warfarin; however, for patients on warfarin therapy treated with ascorbic acid doses up to 1000 mg/day (5 times the largest recommended single dose) for 2 weeks (twice the maximum recommended duration), no effect was observed. Standard monitoring for anti-coagulation therapy should continue during ascorbic acid treatment, as per standard of care.

Laboratory Test Interference

Because ascorbic acid is a strong reducing agent, it can interfere with numerous laboratory tests based on oxidation-reduction reactions (e.g., glucose, nitrite and bilirubin levels, leukocyte count, etc.). Chemical detecting methods based on colorimetric reactions are generally those tests affected. Ascorbic acid may lead to inaccurate results (false negatives) obtained for checking blood or urinary glucose levels, nitrite, bilirubin, and leukocytes if tested during or within 24 hours after infusion.

Pregnancy Risk Summary There are no available data on use of ascorbic acid injection in pregnant women to inform a drug-associated risk of adverse developmental outcomes; however, use of ascorbic acid (vitamin C) has been used during pregnancy for several decades and no adverse developmental outcomes are reported in the published literature. There are dose adjustments for ascorbic acid (vitamin C) use during pregnancy. Animal reproduction studies have not been conducted with ascorbic acid injection.

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in the clinically recognized pregnancies is respectively.

Clinical Considerations Dose Adjustments During Pregnancy and Post-Partum Period Follow the U.S. Recommended Dietary Allowances (RDA) for pregnant women when considering use of Ascorbic acid injection for treatment of scurvy. Data Human Data There are no available data on use of ascorbic acid injection or another ascorbic acid injection in pregnant women.

However, a published meta–analysis of randomized studies evaluating a large number of pregnant women who took oral ascorbic acid (vitamin C) (through diet and supplementation) at doses ranging from 500 to 1000 mg/day (2.5 to 5 times the recommended daily intravenous dose, respectively) between the 9th and 16th weeks of pregnancy showed no increased risk of adverse pregnancy outcomes such as miscarriage, preterm premature rupture of membranes, preterm delivery or pregnancy induced hypertension when compared to placebo. These data cannot definitively establish or exclude the absence of a risk with ascorbic acid (vitamin C) during pregnancy.

Pediatric Use Ascorbic acid injection is indicated for the short term (up to 1 week) treatment of scurvy in pediatric patients age 5 months and older for whom oral administration is not possible, insufficient or contraindicated. The safety profile of ascorbic acid in pediatric patients is similar to adults; however, pediatric patients less than 2 years of age may be at higher risk of oxalate nephropathy following ascorbic acid administration due to age-related decreased glomerular filtration. Ascorbic acid injection is not indicated for use in pediatric patients less than 5 months of age.

Overdose with ascorbic acid may cause nausea, vomiting, diarrhea, facial flushing, rash, headache, fatigue or disturbed sleep. If overdose of ascorbic acid injection occurs, immediately discontinue administration and treat symptoms and signs of overdose, avoiding additional intake of ascorbic acid.