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6.1. Overview of Module 6

This module provides guidance on intravenous vitamin C (IVC) administration for practitioners. It provides what you need to know about prescribing and managing care, including protocols for the two main types of treatment programmes (immune support and support for people with cancer). Later sections cover delivering treatment including preparing solutions and managing any problems during administration.

Following completion of this module the participant will be able to:

Length of activity: 25 min reading
RNZCGP Endorsed: 0.4 credits
CICM Accredited: 0.4 points.

6.2. Introduction

IVC treatment should be carried out by registered clinical practitioners.

This module explains how doctors and nurses at Integrated Health Options (“The Clinic”) in Auckland, New Zealand, conducted IVC treatment for their patients based on scientific evidence and many years of clinical experience.

It is the responsibility of all healthcare practitioners referring to these guidelines to adapt them for safe use within their practice and for the individual needs of their patients.

6.3. Managing care

6.3.1. Prescribing overview

Indications, contra-indications, precautions

This section is a summary. For more detail, refer to the rest of this guideline document.
Treatment Programme
Patient requesting or considering intravenous vitamin C treatment:
Indications - Immune Support
Indications - Cancer Support
Absolute Contra-Indications - for both treatment programmes
Precautions - for both treatment programmes

Interactions with Other Treatments and Investigations

IVC can interact with some other treatments and investigations. Refer to the Stand-down Times section below.

Assessing Risk

When assessing the risk level of IVC treatment for a patient, consider both clinical and ethical factors, including but not limited to:

Low Risk
Riskier - Clinical
Riskier - Ethical

6.3.2. Managing intravenous vitamin C therapy

Indications

Vitamin C infusions are indicated for:

(Biological Therapies and McGuff Pharmaceuticals product datasheets)

Vitamin C infusions are also given for:

Contra-Indications

Treatment Precautions

Renal Stones

Testing Precautions

6.3.3. IVC Treatment protocols

There are slightly different protocols for Immune Support and Cancer Support programmes, described below. They share recommendations for consultation, testing, treatment review, and injectable preparations.

Consultation

Testing

Treatment review

Treatment review is recommended at 2 weeks, 6 weeks, 3 months, 6 months or as indicated by patient needs.

Injectable preparations

Standard clinical practices apply around prescribing for intravenous administration, including taking osmolarity into account. The following is for guidance only, based on clinical experience.

Carrier

The carrier solution for administration can be 0.9% saline, sterile water for injection, or glucose 5%. The dosage of Ascorbic Acid/Sodium Ascorbate may affect which carrier is prescribed.

Ascorbic Acid dose Sodium Ascorbate dose Carrier bag size Saline 0.9% Glucose 5% Water for injection
<50g <50g 250ml Yes Yes Yes
50–100g 50–90g 500ml No No Yes
>100g >90g 1,000ml No No Yes

Additives

Immune support

Treatments are generally recommended 1 – 2 times per week but can be administered more frequently at the doctor's discretion and as indicated by patient needs.

1st treatment
NOTE: Check G6PD prior to 2nd treatment if plan includes doses above 25 g Ascorbic Acid or 30 g Sodium Ascorbate.
2nd and subsequent treatments
Optional

Support for people with cancer

1st treatment
NOTE: Check G6PD prior to 2nd Treatment.
2nd treatment
3rd and subsequent treatments
Optional

6.3.4. Consent for intravenous treatment

It is expected that each clinic will have its own approach to gaining the patient's written informed consent before beginning IVC treatment, reflecting its own professional obligations and advice. For your interest, this section presents one possible approach used at the Clinic.

How is consent understood?

An interactive process between health practitioner and patient

A patient right

Right to make an informed choice and to give informed consent.

“right to information that a reasonable consumer, in that consumer's circumstances, would expect to receive” (Information, choice of treatment and informed consent. Medical Council of NZ, March 2011).

Consent discussion – topics to cover

6.3.5. Managing G6PD deficiency

Some people have a genetic deficiency which may cause haemolysis with high dose intravenous vitamin C (Campbell et al., 1975; Rees et al., 1993; Quinn et al., 2017; Lo & Mok, 2020; Juneja et al., 2022). Testing the patient’s G6PD level before giving any more than 30g of Sodium Ascorbate or 25g of Ascorbic Acid is strongly recommended.

This section describes:

Testing for G6PD Deficiency

(Clinical Experience; Labtests reference range)

If Results are Below 6.9 U/g Hb

(Clinical Experience; advice from Labtests pathologist)

6.3.6. Managing renal function

Poor initial or unnoticed subsequent deterioration in patient renal function may affect ability to handle intravenous vitamin C (IVC) treatment (McAllister et al., 1984; Wong et al., 1994; Alkhunaizi et al., 1996; Malhotra et al., 2020; Maike et al., 2022; Shen et al., 2023). It is advised that the renal function of patients is monitored throughout a course of treatment and that any changes are managed.

Renal Function Testing

(BPAC, 2022; Clinical Experience)

Managing Changes in Renal Function

(Kidney Health New Zealand, 2017; BPAC, 2022; Clinical Experience)

6.3.7. Stand-down times

This section specifies desirable intervals between intravenous vitamin C (IVC) treatment and other forms of medical treatment or investigation.

IVC excretion

Vitamin C is promptly excreted by the kidneys with a half-life of around 2 hours (Stephenson et al., 2013; Nielsen et al., 2015). After an intravenous infusion blood levels of vitamin C return to normal after 8 - 10 hours.

Summary of stand-down periods

Because of potential interactions, a clear period is recommended between IVC and other treatments.

For example, if a patient is scheduled for Chemotherapy on a Wednesday, their previous IVC treatment is recommended to be no later than Monday.

Clear period after IVC, before procedure Procedure Clear period after Procedure, before IVC
24 hours Blood tests Nil
8–10 hours Capillary glucose Nil
24 hours MRI – with contrast 24 hours
Nil MRI – no contrast Nil
24 hours CT scan – with contrast 24 hours
Nil CT scan – no contrast Nil
24 hours PET scan 24 hours
Nil X-Ray Nil
Nil Ultrasound Nil
1 whole day Chemotherapy 2 days
Ask Dr Daily oral chemotherapy Ask Dr
2 whole days Radiotherapy 5 days
24 hours Surgery Nil
24 hours Iron infusion 24 hours

Blood tests

High dose IVC may sometimes cause artefactual lab test results by interference in assays: decreased readings of direct bilirubin, lipase, UIBC, total cholesterol, HDL/LDL cholesterol, triglycerides, and uric acid; increased readings of sodium, potassium, calcium, and creatinine (Meng et al., 2005; Martinello et al., 2006; Yesildal & Isman, 2020).

Blood glucose test strips will show false elevation of readings with raised serum Vitamin C because vitamin C can interfere with the chemical reaction on the glucose strip (Al-Obaidi et al., 2021).

Leave at least 24 hours between IVC infusions and blood tests including renal function or creatinine tests to avoid false readings.

Diabetics

For insulin-dependent patients who rely on test-strip readings for their insulin dose, there is a risk of overdose causing hypoglycaemia (Sartor et al., 2015; Zhang et al., 2020; He et al., 2021).

Diabetic patients should not rely on finger-prick (capillary) glucose tests until 8 - 10 hours after IVC treatment due to false elevation of readings when using test strips – possibly even 12 hours after treatment.

* NOTE: A laboratory serum glucose test is not affected (Jackson et al., 2006).

Scans and imaging

PET scan

Blood glucose levels have a significant influence on PET scans as increased glucose levels can decrease 18F-FDG uptake in the brain and in tumours because of direct competition between binding sites and enzymes, which may lead to a false negative scan (Bahr & Wilson, 2014; Surasi et al., 2014; Sarikaya et al., 2019).

As IVC will cause a falsely elevated reading on point-of-care glucometers therefore, it should be avoided for 24 hours prior to PET scan.

MRI/CT with contrast

Studies showed the contrast materials currently used – e.g. gadolinium for MRI, iodine-based compounds for CT – are generally safe in patients with normal kidney function whereas the incidence of contrast-induced nephropathy (CIN) is as low as 2% (Goldfarb et al., 2009). In these patients, the contrast medium injected is almost entirely passed out of the body within 24 hours.

In rare cases, the contrast can cause nephropathy, mostly in patients with impaired renal function and/or in those with diabetes (Li & Ren, 2020). Kidney dysfunction in CIN is usually reversible, with an acute decline in renal function generally occur within 24 - 72 h after contrast administration and return to baseline within 10 - 14 days (Andreucci et al., 2014; Cho & Ko, 2022).

One study has shown a protective effect on the kidneys of oral Vit C administered before and after contrast (Spargias et al., 2004) but conflicting results were reported in another study whereas combination of vitamin C and Pentoxifylline was administered to patients undergoing angioplasty (Shakeryan et al., 2013).

There were no reported nephropathy issues with IVC at the Clinic, and the Doctors’ consensus was that stand down should be 24 hours before and after CT or MRI with contrast, but oral vitamin C could be continued.

Surgery

Before surgery

Some researchers have shown positive effects of IV vitamin C administered just before and during surgery, such as less pain relief needed after surgery, less incidence of myocardial injury and less postoperative pulmonary complications after cardiac surgery, but only at lower doses, such as a few grams (Wang et al., 2014; Ayatollahi et al., 2017; Wang et al., 2020).

As IVC can affect blood test results, it is best to avoid IVC for 24 hours before surgery.

Anaesthesia

One study has shown reduced dosage of anaesthetics in patients undergoing total knee replacement surgery who received preoperative vitamin C infusion (Li et al., 2021). Animal studies suggest that vitamin C (given intramuscularly) before anaesthetic potentiates or enhances the effects of some anaesthetic agents (Elsa et al., 2005, Najafpour et al., 2007).

Recommendations regarding IVC and anaesthetic are the same as those for surgery.

After surgery

No stand down time is needed if the patient is able to attend.

Chemotherapy and radiotherapy

The results of recent clinical trials showed that combining IVC with chemotherapy and/or radiotherapy appeared to be safe, well tolerated and could effectively decrease standard therapy associated side effects (Bael et al., 2008; Monti et al., 2012; Welsh et al., 2013; Kawada et al., 2014; Ma et al., 2014; Hoffer et al., 2015; Schoenfeld et al., 2017; Zhao et al., 2018; Carr et al., 2018; Mansoor et al., 2021).

However, due to their small sample sizes and limited studies, it is recommended patients avoid IVC one day before and two days after chemotherapy; avoid IVC two days before and five days after radiotherapy.

If oral chemotherapy is given every day, normal stand-down times do not apply. Some of the clinical trials used IVC in conjunction with oral chemotherapy which seems to be safe, well tolerated and may synergistically increase survival time in some tumours (Bael et al., 2008; Schoenfeld et al., 2017; Allen et al., 2019). IVC may be given on a case by case basis after discussion with the patient.

Iron infusion

Ferinject or other iron infusion. Mean plasma clearance range from 2.6 – 4.4 mL/min and terminal half-life from 7 – 12 h (Medsafe Ferinject Datasheet, 2021).

There are theoretical concerns that some of the circulating iron may be chelated by the vitamin C or that vitamin C and high concentrations of infused iron may enhance free radical generation via the Fenton reaction, which results in tissue damage (Kontoghiorghes et al, 2020; Pal & Jana, 2020).

In the absence of published evidence of the safety of combining these treatments, it is advisable to leave 24 hours before and after iron infusion.

Additional resources:

References – 6.3.7. Stand-down times (PDF)

6.3.8. Possible Effects of IVC – Patient Guidance

The following is material the Clinic provided to patients:

Common effects

During and after an infusion of vitamin C, you may experience some common effects. Most are mild and may last up to a few hours.

Uncommon effects

There are also several possible effects which are not common, and require medical attention:

6.4. Delivering treatment

6.4.1. Equipment needed

Prepared IV bag with additives and primed IV giving set, tourniquet, selected butterfly or cannula needle, alcohol swabs, gauze square, prepared tape and/or opsite, felt tip pen.

6.4.2. Storing supplies

Store and dispose of injectables and other supplies as directed on their packaging and datasheets.

Ascorbic Acid or Sodium Ascorbate for injection should be kept refrigerated.

6.4.3. Preparing intravenous solutions

Each clinic has its own way of managing the preparation of IV bags. These are some helpful tips the Clinic picked up during its practice:

Using Ascorbic Acid

The two forms of injectable vitamin C used are Ascorbic Acid or Sodium Ascorbate.

Ascorbic Acid Sodium Ascorbate
Concentration 25g / 50mL 30g / 100mL
Vial volume 50mL 100mL

Carrier solutions

The carrier solution for administration can be 0.9% saline, sterile water for injection, or glucose 5%.

The dosage of Ascorbic Acid/Sodium Ascorbate may affect which carrier is prescribed. For more details, see the Injectable Preparations section above.

Bag volumes

The following are the Clinics recommendations for preparing solutions. Bag draining may be required.

Ascorbic Acid (50 mL vial)
Ascorbic Acid dose Bag preparation
< 50g Use a standard 250 mL bag of carrier solution.
50–100g Use a 500 mL bag of sterile water for injection.
> 100g Drain 200 mL or more from a 1,000 mL bag of sterile water for injection.
Sodium Ascorbate (100 mL vial)
Sodium Ascorbate dose Bag preparation
< 35g Use a standard 250 mL bag of carrier solution.
35–49g Drain 50 mL from a standard 250 mL bag.
50–90g Drain 100 mL from a 500 mL bag of sterile water for injection.
> 90g Drain 200 mL or more from a 1000 mL bag of sterile water for injection.

Calculate drip rate

Infusion rate for intravenous vitamin C must be no faster than 1 gram per minute.

Calculate: minimum* time (minutes) = IVC dose (grams),

(volume (mL) × drip factor (drops/mL)) ÷ time (minutes) = drips per minute

* Adjust upwards depending on the patient. Use a lower rate for first treatment/s and monitor tolerance.

6.4.4. Administering infusions

Pre-treatment patient check

As part of our standard clinical care, the Clinic's nurses administered a brief check before each treatment session. If there are any concerns about a patient's readiness for treatment, then an urgent doctor consultation is arranged. Questions, along the lines of the following can be asked:

Infusing

These are The Clinic's guidelines for administering an infusion:

6.4.5. Managing infusion problems

Emergencies

If a patient's condition requires urgent medical attention, follow your emergency procedures. Examples are: anaphylaxis, choking, collapse, hypocalcaemia, hypoglycaemia.

Symptoms and problems

SYMPTOMS

EXPLANATION

Pain

Discomfort

If patient complains of pain, act immediately. The patient may also feel faint because of the pain.

ACTION

  • Assess site for swelling, redness and pain.
  • If no concerns and butterfly/cannula blood flashback is confirmed then proceed with IV.
  • A slight reposition of the needle may resolve discomfort.
  • Apply heat pack to the affected area either above or below the site (aching in the arm may be due to the infusion rate being too fast or the solution being too cold).
  • If it does not resolve, re-site IV with patient consent.

Swelling

Discomfort

Burning

Pain

Tightness

Extravasation

IV fluid may leak into the surrounding tissue. It is commonly caused by needle dislodgement, patient movement or improper placement of the needle. The risk increases in older patients as their veins are thin and fragile.

ACTION

  • Stop the infusion immediately and assess for swelling at the site.
  • If extravasation has occurred, stop the IV infusion.
  • Remove the IV needle immediately. Protect the exposed end of the IV giving set with a luer lock (see 'Avoiding Contamination' section below).
  • Apply pressure and an ice pack for pain and swelling.
  • Explain to patient what has happened and prepare patient for insertion of another IV line.
  • Once patient is ready to proceed, re-site the IV needle adhering to proper technique, either above the site or on the other arm. See SP 307 Needle Insertion.

Nausea

Trembling/shakiness

Blurry vision

Headache

Decreased co-ordination

Impaired judgement

This may be due to hypoglycaemic effect of IVC.

Once resolved, remind patient to eat before IV treatment, and to have a snack during the IV treatment.

ACTION

  • Stop the infusion.
  • If symptoms are Moderate to Severe, give 2 tsp glucose dissolved in water or in fruit juice.
  • If symptoms are Mild, give drink of fruit juice.
  • If symptoms still persist, give 1 tsp of cal/mag citrate powder dissolved in either water or fruit juice.
  • Monitor patient, restart infusion as tolerated when symptoms resolve.

Tingling mouth or extremities

Numbness

Muscle spasm/cramp

Diplopia

Stridor

Tetany

Convulsions

Positive Trousseaux and Chvostek signs

This may be due to hypocalcaemic effect of IVC.

ACTION

  • Stop the infusion.
  • Give 1 tsp of glucose and 1 tsp of cal-mag citrate powder dissolved in either water or juice.
  • Monitor patient and restart infusion once symptoms have resolved.
  • If symptoms persist after 15 minutes, give another 1 tsp of glucose and 1 tsp of cal-mag citrate powder dissolved in either water or juice.
  • If symptoms persist, treat as a medical emergency.
  • Consider testing serum calcium at time of event and renal function 24 hours later.

Lightheaded

Faint

ACTION

  • Slow IV rate, tilt the chair and place pillows to raise feet.
  • Assess colour and breathing.
  • Talk quietly to give reassurance.
  • Take BP and pulse.
  • Place cool flannel on forehead.
  • When possible, provide a glucose drink (two tsp dissolved in fruit juice). Report to doctor.

Arm numbness

May be caused by arm position.

ACTION

  • Reposition pillows and advise to move fingers to increase circulation
  • If this does not resolve, stop the infusion, inform the doctor and if appropriate re-site the IV needle to the other arm.

Preventing contamination

If the IV needle has to be re-sited, protect the IV giving set from contamination. Once the needle is removed, disconnect it from the giving set and attach a blue luer lock to the exposed end of the giving set.

Discard the IV needle, following your clinic's Infection Control procedure.

Preventing haematoma

After removal of IV needle, ensure the patient knows to apply pressure to the site for a minimum of three minutes.

If patient is on blood thinning medication encourage them to hold the site for longer; up to 5 minutes. Consider using an IV pressure pad for these patients.

Documentation

Any problems that have occurred during the patient's IV treatment should be recorded in your patient management system.

6.5. Summary of Module 6

6.6. Activity: Self-reflection and feedback

Once you have completed all the Modules of interest to you, please complete the self-reflection and feedback form online or email to anitra.carr@otago.ac.nz. For members of the RNZCGP, please include your MCNZ number and the modules completed so that your CPD credits can be uploaded to the RNZCGP website. A certificate of completion can be emailed to you if required.

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"This link leads to the website 'Oral and intravenous vitamin C use in health care' provided by the Nutrition in Medicine Research Group at University of Otago, Christchurch."

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