Ascorbic acid

Oral
Scurvy
Adult: As treatment: Not less than 250 mg daily in divided doses. Max: 1000 mg daily. As prophylaxis: 25-75 mg daily. Doses are individualised according to patient's needs. Dosage recommendation may vary among countries or individual products. Refer to specific product guidelines.
Child: Dosage recommendation may vary among countries or individual products. Refer to specific product guidelines.
Renal impairment: ESRD: 60-100 mg once daily.

Parenteral
Scurvy
Adult: 300-1000 mg daily, given via IM, IV or SC inj. Doses are individualised according to patient's needs. Dosage recommendation may vary among countries or individual products. Refer to specific product guidelines.
Child: Initially, 100-300 mg daily in divided doses for 1 week then 100 mg daily until stabilisation of tissue saturation. Dosage recommendation may vary among countries or individual products. Refer to specific product guidelines.
Reconstitution: IV: Add a daily dose to an appropriate volume of suitable solution (e.g. 5% dextrose in water, sterile water for inj). Add the solutes as necessary to make the final solution isotonic. Instructions for reconstitution may vary among countries or individual products. Refer to specific product guidelines.
Incompatibility: Incompatible with ferric salts, oxidising agents, salts of heavy metals (e.g. Cu), aminophylline, bleomycin sulfate, erythromycin lactobionate, nafcillin Na, nitrofurantoin Na, conjugated estrogens, Na bicarbonate, sulfafurazole diethanolamine. Occasionally, chloramphenicol Na succinate (depending on pH or concentration).

May be taken with or without food.

Patient with diabetes mellitus, G6PD deficiency, haemochromatosis, history of renal stones (e.g. oxalate kidney stones), predisposition to recurrent renal calculi. Renal impairment. Children (<2 years of age) and elderly. Pregnancy and lactation. Monitoring Parameters Monitor renal function (patient with a predisposition to oxalate nephropathy), haemoglobin, and blood counts (G6PD deficient patient).

Significant: Acute or chronic oxalate nephropathy (prolonged use; large doses). Gastrointestinal disorders: Diarrhoea, nausea, vomiting, heartburn. General disorders and administration site conditions: Fatigue, pain at the inj site. Nervous system disorders: Dizziness, headache. Vascular disorders: Flushing.

Symptoms: Diarrhoea, formation of renal oxalate calculi. Management: Supportive and symptomatic treatment.

Increased absorption of Fe. Increased excretion of Fe with desferrioxamine. Induced tissue desaturation with aspirin, nicotine, Fe, phenytoin, tetracycline, estrogen in oral contraceptives, some appetite suppressants and anticonvulsants. May increase the absorption of Al-containing antacids. May diminish the activity of anticoagulants (e.g. warfarin). May increase the serum concentration of estrogen derivatives. May decrease the serum concentration of amphetamines.

Alcohol may decrease ascorbic acid levels.

May interfere test results based on oxidation-reduction reactions (e.g. leucocyte count, blood and urine glucose testing, nitrite and bilirubin levels). May cause false-negative faecal occult blood test.

Ascorbic acid, a water-soluble vitamin that acts as a cofactor and as an antioxidant. It is essential for connective tissue synthesis, and Fe absorption and storage. Additionally, it is an electron donor used for collagen hydroxylation, carnitine biosynthesis, and hormone or amino acid synthesis. Synonym: vitamin C.
Onset: 2 days to 3 weeks (reversal of scurvy symptoms).
Absorption: Well absorbed from the gastrointestinal tract. Bioavailability: Approx 100% (Oral: for doses up to 200 mg).
Distribution: Crosses the placenta, enters breast milk. Widely distributed in the body tissues; distributed to the pituitary and adrenal glands, eye tissues and humours, leucocytes, and brain; low concentration in the plasma and saliva.
Metabolism: Reversibly metabolised via oxidation into dehydroascorbic acid (active), partly metabolised to inactive compounds including ascorbic-acid-2-sulfate and oxalic acid.
Excretion: Via urine (with high concentrations); minimal excretion in subthreshold levels (up to 80 mg/day). Elimination half-life: 10 hours.

Oral: Store below 25°C. Parenteral: Store between 2-8°C. Protect from light.

Vitamin C

S01XA15 - ascorbic acid ; Belongs to the class of other ophthalmologicals.
G01AD03 - ascorbic acid ; Belongs to the class of organic acid antiinfectives. Used in the treatment of gynecological infections.