Possible side effects include:

  • Finger-stick glucose monitoring could be abnormal for 1–6 hours after IV C.
  • Side effects reported in clinical trials providing high-dose IV C have included nausea, dizziness, dry mouth, fatigue, perspiration, and weakness. Such effects are not likely to occur with 5–25 g (low-dose) IV C; however, caution is advised.

High dose IV vitamin C, in particular, is a valuable therapeutically because it has been shown to exert effects similar to prescription antibiotics, anti-inflammatories, anti-histamines and smooth muscle relaxants without many side effects or toxicity. An IV treatment of vitamin C can raise the blood levels 50 – 100 times higher than oral supplementation. Therefore, the common side effect of diarrhea, normally associated with high dose ORAL vitamin C, can be avoided.