Ascorbic acid (Vitamin C) is a water soluble vitamin essential for the synthesis of collagen and intercellular material. It functions as a co-factor in a number of hydroxylation and amidation reactions by transferring electrons to enzymes that provide reducing equivalents. Ascorbic acid also promotes intestinal absorption of iron, microsomal drug metabolism and synthesis of norepinephrine, carmitine etc.
Deficiency of vitamin C may develop when the dietary intake is inadequate. It is rare in adults but may occur in infants, alcoholics or the elderly.
Deficiency of vitamin C results in a well-defined syndrome called Scurvy. This is associated with a defect in collagen synthesis that results in failure of wounds to heal, defects in tooth formation, rupture of capillaries which leads to bleeding (especially from small blood vessels and the gums), numerous petechiae and their coalescence to form ecchymoses. Vitamin c is thus used in the treatment and prevention of scurvy
A daily intake of about 30 to 60 mg is recommended for adults. There is however, wide variation in individual requirements. Dietary ascorbic acid is obtained from fruits and vegetable sources like black currant, citrus fruits, leafy vegetables, tomatoes, potatoes, green and red peppers. Ascorbic acid is readily destroyed during cooking processes.
Vitamin C is readily absorbed from the gastrointestinal tract and is widely distributed in the body tissues. The concentration is higher in leukocytes and platelets than in erythrocytes and plasma. In deficiency states the concentration in leukocytes declines later and at a slower rate
Ascorbic acid is reversibly oxidized o dehydroascorbic acid, some is metabolized to ascorbate-2-sulphate which is inactive and oxalic acid which is excreted in the urine.
Ascorbic acid in excess of body needs is rapidily excreted unchanged in the urine.
Ascorbic acid crosses the placenta and is also distributed into breast milk
Dosage and administration
As directed by the physician/pharmacist as under.
Up to 1g daily in divided doses have been used.
Ascorbic acid 100 tablets: 1-3 tablets daily to be sucked or chewed before swallowing
Ascorbic acid – 200 tablets: 1-3 tablets daily to be sucked or chewed before swallowing
Adverse / side effects
Acorbic acid is usually well tolerated. Large doses may cause diarrhea and other gastro-intestinal disturbances. Large doses may result in hyperoxaluria and the formation of renal calcium oxalate calculi.
Care is required in patients with hyperoxaluria. Caution is required if co-administration with desferrrioxamine is indicated. Tolerance may be induced with prolonged use of large doses