Ascorbic acid is usually administered orally. When oral administration is not feasible or when malabsorption is suspected, the drug may be administered intramuscularly, intravenously or subcutaneously. When given parenterally, utilization of the vitamin reportedly is best after IM administration, which is the preferred parenteral route.
For intravenous injection, dilution into a large volume parenteral such as Normal Saline or Glucose is recommended to minimize the adverse reactions associated with intravenous injection.
The average protective dose of ascorbic acid for adults is 70 to 150 mg daily. In the presence of scurvy, doses of 300 mg to 1 gram daily are recommended. However, as much as 6 grams have been administered parenterally to normal adults without evidence of toxicity.
To enhance wound-healing, doses of 300 to 500 mg daily for a week to ten days, both preoperatively and postoperatively, are generally considered adequate, although considerably larger amounts have been recommended. In the treatment of burns, doses are governed by the extent of tissue injury. For severe burns, daily doses of 1 to 2 grams are recommended. In other conditions in which the need for ascorbic acid is increased, three to five times the daily optimum allowances appear to be adequate.