Safe Use of High-Dose Intravenous Vitamin C in Oncology Care

The Dark Side of High-Dose Intravenous Vitamin C in Oncology Care

High-dose intravenous vitamin C (IVC) is a recognised adjunctive therapy in integrative oncology. Decades of clinical experience—guided by protocols such as the Riordan Clinic protocol—demonstrate that IVC can be delivered safely and effectively.

However, this is not a “simple infusion.” Administering IVC in megadoses requires specialist medical training. Oncology patients are medically fragile, and improper preparation or delivery can cause severe harm. Merely inserting a cannula and sourcing vitamin C does not make a provider competent to administer IVC.

1. Patient Selection and Pre-Treatment Assessment

Before the first infusion, a full medical assessment is essential:

• G6PD deficiency must be excluded: deficiency can cause haemolysis with high-dose vitamin C.

• Renal function should be assessed: vitamin C increases urinary oxalate, which may precipitate in susceptible patients.

• Oncology context: Broadly speaking, IVC is not a cancer cure, but it can be an adjunct to support wellbeing, reduce oxidative stress, and improve tolerance to conventional treatments.

2. Fluid Choice and Dosing Structure

The Riordan protocol stresses the importance of carefully titrating the vitamin C dose and selecting an appropriate infusion fluid. While lower doses can be safely diluted in standard 0.9% saline, intermediate and high doses require a tailored fluid strategy to maintain safe osmolarity and minimise the risk of electrolyte disturbances.

3. Electrolyte and Infusion Adjustments

High-dose vitamin C infusions can shift electrolytes, and safe administration requires anticipation and correction:

• Calcium and magnesium: temporary drops may occur. Symptomatic patients may require IV calcium gluconate or magnesium supplementation to avoid seizures.

• Potassium: may also fluctuate; close monitoring is advised, especially in oncology patients with reduced reserves. to avoid sudden cardiac events including death.

• Sodium: Vitamin C infusions often use sodium ascorbate, which provides a significant sodium load. This formulation is necessary because ascorbic acid is highly acidic and must be buffered with an alkaline agent, typically sodium bicarbonate, to make it suitable for intravenous administration. Standard infusion fluids, such as 0.9% saline, already contain sodium at physiological concentrations, so adding high-dose sodium ascorbate further increases both the sodium content and osmolarity of the infusion. Elevated sodium levels, or hypernatremia, can be dangerous if not anticipated and managed, potentially causing brain cell injury., cerebral bleeding, permanent brain damage and death secondary to brain shrinkage with acute hypernatraemia (referrence).

• Glucose monitoring: Point-of-care glucose meters can produce falsely elevated or inaccurate readings in the presence of high-dose vitamin C. Clinicians must interpret results cautiously and rely on clinical judgement when managing hypoglycemia, given the potential risk of neurological injury if left untreated.

4. Monitoring During Infusion

IVC must be administered slowly and with continuous clinical monitoring:

• ECG monitoring is advised at higher doses or if calcium support is given.

• Observation for infusion reactions such as vein irritation, lightheadedness, or electrolyte-related symptoms.

• Renal monitoring over the course of therapy, especially with repeated high doses.

5. Risks if Performed Outside Clinical Oversight

Administering IVC without proper medical oversight carries serious risks:

• Hemolysis if G6PD status is not checked.

• Acute kidney injury if renal function is ignored or fluids are not properly matched to dose.

• Electrolyte crises if disturbances are not recognised or corrected.

• Infusion line complications if osmolarity and dilution are not calculated correctly the veins may become scarred from only few infusions, denying the patient the chance of future life-inhancing therpies.

These are not theoretical risks—they are known medical realities. For oncology patients, who are often immunocompromised and metabolically fragile, safety margins are narrow.

Conclusion

High-dose IVC can be a valuable part of integrative oncology care, but only when used under strict medical supervision. It requires:

• A prescribing doctor with oncology and infusion expertise,

• Careful adjustment of dose, fluid type, and infusion rate,

• Continuous monitoring and readiness to correct electrolyte shifts,

  
  

At Leicester Ozone Clinic, our commitment is to deliver IVC safely and professionally, recognising that in oncology, every detail matters.