4.1 Therapeutic indication
For the prevention and treatment of Vitamin C deficiency
4.2 Posology and method of administration
Method of administration
Vitamin C Chewable Tablets are to be chewed before swallowing.
Posology
- Adults and Children > 12 years: 1-2 tablets per day (equivalent to 500 or 1000 mg/day) until symptoms subside.
- Children 6-12 years: 1 tablet per day (equivalent to 500 mg/day) until symptoms subside.
- Vitamin C Chewable Tablets are not recommended for children under 6 years.
4.3 Contraindications
- Hypersensitivity to the active substance or to any of the excipients.
- Ascorbic acid should not be given to patients with hyperoxaluria.
- Oxalate urolithiasis and iron storage diseases (thalassaemia, haemochromatosis, sideroblastic anaemia) or other medical conditions that predispose individuals to iron overload.
4.4 Special warnings and precautions for use
a. Increased intake of ascorbic acid over a prolonged period may result in an increased renal clearance of ascorbic acid, and deficiency may result if the intake is reduced or withdrawn rapidly.
b. Exceeding the recommended dose should be avoided as there have been isolated reports of severe haemolysis in patients with erythrocytic glucose-6-phosphate dehydrogenase deficiency when taking high doses (> 4000 mg/day) of ascorbic acid. Do not exceed the recommended dose.
c. Caution is required and use the minimum recommended dose in patients with renal impairment.
d. Patients with rare hereditary fructose intolerance, glucose-galactose malabsorption or sucraseisomaltase deficiency should not take ascorbic acid.
e. Interference with serological testing
- Ascorbic acid may interfere with tests and assays for urinary glucose, giving false-negative results with methods utilising glucose oxidase with indicator and false-positive results with neocuproine methods.
- Estimation of uric acid by phosphotungstate or uricase with copper reduction and measurement of creatinine in non-deproteinised serum may also be affected.
- High doses of ascorbic acid may give false-negative readings in faecal occult blood tests.
- Patients with rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption should not take this medicine.
4.5 Drugs interactions
- Ascorbic acid increases the renal excretion of amphetamine.
- The plasma concentration of ascorbate is decreased by smoking and oral contraceptives.
- Ascorbic acid increases the absorption of iron. This should be borne in mind in the case of iron replacement.
- Concomitant administration of aspirin and ascorbic acid may interfere with absorption of ascorbic acid. Renal excretion of salicylate is not affected and does not lead to reduced anti-inflammatory effects of aspirin.
- Concomitant administration of aluminium-containing antacids may increase urinary aluminium elimination. Concurrent administration of antacids and ascorbic acid is not recommended, especially in patients with renal insufficiency.
- Co-administration with amygdalin (a complementary medicine) can cause cyanide toxicity.
- Concurrent administration of ascorbic acid with desferrioxamine enhances urinary iron excretion. Cases of cardiomyopathy and congestive heart failure have been reported in patients with idiopathic haemochromatosis and thalassaemias receiving desferrioxamine who were subsequently given ascorbic acid. Ascorbic acid should be used with caution in these patients and cardiac function monitored.
- Ascorbic acid may interfere with biochemical determinations of creatinine, uric acid and glucose in samples of blood and urine.
4.6 Use in special populations
Pregnancy
For ascorbic acid no clinical data on exposed pregnancies are available. Animal studies do not indicate direct or harmful effects with respect to pregnancy, embryonal/foetal development, parturition or postnatal development. Pregnant women should exercise caution.
Breast-feeding
Ascorbic acid is excreted in breast milk. Though again caution should be exercised, no evidence exists suggesting such excretion is hazardous to the infant.
4.7 Effects on ability to drive and use machines
On the basis of the product's pharmacodynamic profile and reported adverse events, ascorbic acid has no known effect on an individual's ability to drive or operate machinery.
4.8 Undesirable effects
- Nervous system disorders: headache.
- Vascular disorders: flushing.
- Gastrointestinal disorders: Nausea, vomiting and stomach cramps. Large doses of ascorbic acid may cause diarrhoea.
- Skin and subcutaneous tissue disorders: redness of skin.
- Renal and urinary disorders: Patients known to be at risk of hyperoxaluria should not ingest ascorbic acid doses exceeding 1g daily as there may be increased urinary oxalate excretion. However, such risk has not been demonstrated in normal, non-hyper oxaluric individuals. Ascorbic acid has been implicated in precipitating haemolytic anaemia in certain individuals deficient of glucose-6-phosphate dehydrogenase. Increased intake of ascorbic acid over a prolonged period may result in increased renal clearance of ascorbic acid, and deficiency may result if the intake is reduced or withdrawn rapidly. Doses of more than 600mg daily have a diuretic effect.
- Reporting of suspected adverse reactions Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via email to: medico@zuventus.com Website: https://www.zuventus.com/drug-safety-reporting By reporting side effects, you can help provide more information on the safety of this medicine.
4.9 Overdose
Symptoms: At doses of over 3g per day unabsorbed ascorbic acid is mainly excreted unmetabolised in the faeces. Absorbed ascorbic acid additional to the body's needs is rapidly eliminated. Large doses of ascorbic acid may cause diarrhoea and the formation of renal oxalate calculi. Symptomatic treatment may be required. Ascorbic acid may cause acidosis or haemolytic anaemia in certain individuals with a deficiency of glucose 6-phosphate dehydrogenase. Renal failure can occur with massive ascorbic acid overdosage.
Management: Gastric lavage may be given if ingestion is recent otherwise general supportive measure should be employed as required.