Ascorbate

From Anvita Health Wiki

Contents 1 Indications 2 Dosage 3 Pharmacokinetics 4 Adverse-effects 5 Drug-interactions 6 Test-interactions 7 Mechanism-of-action 8 More General Terms 9 Additional Terms 10 Internet Database 11 References

Indications

• (uses)
• prevention & treatment of scurvy
• acidification of urine
• enhanced wound healing
• severe burns
• hyperuricemia/ gout

Dosage

• prevention & treatment of scurvy

• RDA: 60 mg QD ( PO IM, SC,IV)
• average protective dose 70-150 mg QD
• scurvy: 300 mg to 1 g QD

• acidification of urine: 4-12 g QD divided TID/ QID
• enhanced wound healing: 300-500 mg QD for 7-10 days
• severe burns: 1-2 g/day
• hyperuricemia/ gout: 500 mg QD [4]

Pharmacokinetics

• Tissues that accumulate ascorbate include: [6]

• those with > 100 fold blood plasma vitamin C adrenal, pituitary, thymus, corpus luteum, retina
• those with 10-50 fold blood plasma vitamin C brain, spleen, lung, testicle, lymph nodes, liver, thyroid, small intestinal mucosa, leukocytes, pancreas, kidney, salivary glands
  

• elimination via kidney

Adverse-effects

• not common (1-10%)

• hyperoxaluria

• uncommon (< 1%)

• flushing, faintness, dizziness, headache, nausea/vomiting, heartburn, diarrhea, fatigue

Drug-interactions

• ascorbate may affect propranolol absorbtion & 1st pass metabolism in the liver
• ascorbate may increase serum levels of estrogen
• ascorbate may decrease anticoagulant effect of warfarin

Test-interactions

• may falsely elevate serum creatinine [3]

Mechanism-of-action

• reducing agent, oxidized to L-dehydroascorbate which is in turn reduced ezymatically or by glutathione
• ascorbate is an electron donor for 8 different enzymes

• for 3 of these enzymes, ascorbate is a cofactor in hydroxlation of Lys & Pro in collagen type-1 (& other collagens)
• for 2 of these enzymes, ascorbate is a cofactor in synthesis of carnitine
• ascorbate is a cofactor fof dopamine beta hydroxylase in the biosynthesis of norepinephrine from dopamine
• ascorbate is a cofactor for an enzyme that adds amide groups to peptide hormones, increasing their stability
• ascorbate is a cofactor for an enzyme that modulates tyrosine metabolism

• substrate of ascorbate peroxidase [6]

More General Terms

• sugar acid
• vitamin

Additional Terms

• ascorbate in blood/buffy coat/plasma/serum
• scurvy (vitamin C deficiency)

Internet Database

Kegg: [1]
PubChem: 235
PubChem: 5785
PubChem: 114765
PubChem: 439159
PubChem: 22878
PubChem: 62785
PubChem: 21967

References

1. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
2. Kaiser Permanente Northern California Regional Drug Formulary, 1998
3. Prescriber's Letter 9(5):28 2002
4. Journal Watch 25(14):114-15, 2005 Huang HY, Appel LJ, Choi MJ, Gelber AC, Charleston J, Norkus EP, Miller ER 3rd. The effects of vitamin C supplementation on serum concentrations of uric acid: results of a randomized controlled trial. Arthritis Rheum. 2005 Jun;52(6):1843-7. PMID: [2]
5. Department of Veterans Affairs, VA National Formulary
6. Wikipedia - vitamin C entry [3]

ascorbate; ascorbic acid; vitamin C