ASCOR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ASCOR (ASCOR).
Ascorbic acid (vitamin C) acts as an antioxidant and a cofactor for several enzymes involved in collagen synthesis, carnitine biosynthesis, and neurotransmitter synthesis. It facilitates iron absorption from the gastrointestinal tract and participates in immune function.
| Metabolism | Ascorbic acid is partially metabolized in the liver to inactive metabolites including oxalic acid, threonic acid, and ascorbate-2-sulfate. Major route: renal excretion of unchanged drug and metabolites. |
| Excretion | Renal: 70-90% (as unchanged drug and metabolites), biliary/fecal: minor (<10%) |
| Half-life | Terminal elimination half-life is 8-12 hours in patients with normal renal function; prolonged to 24-48 hours in renal impairment, requiring dose adjustment. |
| Protein binding | 55-65% bound to plasma proteins, primarily albumin |
| Volume of Distribution | 0.2-0.3 L/kg, indicating distribution primarily in extracellular fluid. |
| Bioavailability | Oral: 75-85%, reduced by food; Intravenous: 100% |
| Onset of Action | Oral: 30-60 minutes; Intravenous: 5-10 minutes |
| Duration of Action | 6-8 hours; clinical effect may persist longer with higher doses or in renal impairment. |
1 tablet (75 mg) orally once daily for antiplatelet effect; for acute coronary syndrome: initial dose 300 mg orally, then 75 mg orally once daily.
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required for any degree of renal impairment. Aspirin is contraindicated in severe renal failure (GFR <10 mL/min) due to risk of accumulation. |
| Liver impairment | Contraindicated in severe hepatic impairment (Child-Pugh class C). In moderate impairment (Child-Pugh class B), use with caution; no specific dose adjustment, but monitor for bleeding. |
| Pediatric use | Antiplatelet therapy: 1-5 mg/kg orally once daily; for Kawasaki disease: 80-100 mg/kg/day orally divided every 6 hours for 14 days, then 3-5 mg/kg/day orally once daily. Contraindicated in viral illness due to Reye syndrome risk. |
| Geriatric use | No specific dose adjustment; monitor renal function and bleeding risk. Lower doses (75 mg/day) are typically sufficient for antiplatelet effect. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ASCOR (ASCOR).
| Breastfeeding | Ascorbic acid is excreted into breast milk with M/P ratio ~1.0. Recommended dietary allowance is 120 mg/day. High doses may cause infant gastrointestinal upset. Generally safe. |
| Teratogenic Risk | ASCOR (ascorbic acid) at recommended doses is not teratogenic. High doses (>1000 mg/day) may theoretically cause fetal ascorbic acid dependence, but risk is minimal. No known congenital anomalies. |
| Fetal Monitoring |
■ FDA Black Box Warning
No FDA boxed warning exists for ascorbic acid.
| Serious Effects |
["Hypersensitivity to ascorbic acid or any formulation components","Hyperoxaluria","Renal oxalate stones (history)","Iron overload disorders (e.g., hemochromatosis, thalassemia) – relative contraindication"]
| Precautions | ["High doses may cause diarrhea, renal oxalate stones, and iron overload in predisposed individuals (e.g., hemochromatosis).","Patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency may develop hemolysis.","May interfere with laboratory tests (e.g., glucose, bilirubin)."] |
| Food/Dietary | No significant dietary restrictions. Vitamin C enhances iron absorption from plant-based foods; take with meals if increased iron absorption is desired. Avoid excessive intake of foods high in oxalates (e.g., spinach, rhubarb, beets) when taking high-dose vitamin C, as it may increase risk of kidney stones. |
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| No specific monitoring required. For prolonged high-dose supplementation, observe for maternal gastrointestinal effects (diarrhea, cramps). |
| Fertility Effects | No adverse effects on fertility at recommended doses. High doses may theoretically cause fetal ascorbic acid dependence but no human data. |
| Clinical Pearls | Ascorbic acid (vitamin C) is water-soluble and renally excreted; doses >200 mg may cause false-negative fecal occult blood tests due to antioxidant interference. High-dose IV vitamin C may cause hemolysis in G6PD deficiency. Use with caution in renal impairment due to oxalate stone formation. For scurvy, give 100 mg PO TID for 1 week, then 100 mg daily. In iron overload, vitamin C can increase iron absorption and cause tissue damage. |
| Patient Advice | Take vitamin C exactly as directed; do not exceed recommended doses without consulting your doctor. · If you have a history of kidney stones, diabetes, or G6PD deficiency, discuss vitamin C use with your healthcare provider. · High doses may cause diarrhea, nausea, or stomach cramps; reduce dose if these occur. · Do not take vitamin C supplements if you have iron overload disorders (e.g., hemochromatosis) unless advised by your doctor. · Inform your doctor if you are taking blood thinners or have scheduled lab tests, as vitamin C can interfere with certain tests (e.g., glucose, fecal occult blood). · Store at room temperature, away from light and moisture. Do not freeze liquid forms. |