Ordinarily, one function of GSH is to reduce dehydroascorbate back to ascorbate. The sicker these patients are, the more ascorbic acid in water they will tolerate orally before it produces diarrhoea. The patient titrates the dose until it relieves the toxic symptoms or almost produces diarrhoea. During a crisis, doses may be taken every 15 min, but when the patient is completely symptom- free, doses may be taken only six times a day. The incidence of allergic reactions to antibiotics used in the treatment of PCP is much reduced.
Patients report an almost complete elimination of malaise except during acute complications.
Oral ascorbic acid is administered to tolerance at the same time. The diarrhoea is thought to be due to the hyperosmotic concentration of the ascorbate reaching the rectum. Intravenous ascorbate does not produce diarrhoea and it increases oral tolerance. I think this tolerance is caused by utilization of ascorbate as a free-radical scavenger when scavengers such as glutathione are exhausted.