• Hypersensitivity to the active substance or to any of the excipients of the drug.
• Ascorbic acid should not be given to patients with hyperoxaluria.

Warnings and precautions
Talk to your doctor or pharmacist before taking Vitamin C tablets:

• Increased intake of ascorbic acid over a prolonged period may result in an increase in renal
  clearance of ascorbic acid and deficiency may result if it is withdrawn rapidly.
• Ascorbic acid may interfere with tests and assays for urinary glucose, giving false-negative
  results with methods utilising glucose oxidase with indicator (e.g. Labstix, Tes-Tape) and falsepositive 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.

Other medicines and Vitamin C Tablets
Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines. This is particularly important if you are taking any of the following:

• 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.
• 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 antiinflammatory 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.
  If you need to have a blood or urine test you should tell the doctor or nurse you are taking these tablets as they may interfere with the results.

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.
If you are pregnant, think you may be pregnant or are planning to have a baby, ask you doctor or pharmacist for advice before taking this medicine.

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.
If you want to breast-feed your baby you should talk to your doctor first before taking these tablets.