Dexamethasone - your questions answered from research

Dexamethasone - your questions answered from research

Cancer patients are invariably given a corticosteroid Dexamethasone with their IV drug combinations, despite side-effects such as reducing white blood cell levels, reducing the diversity of the microbiome, and promoting blood sugar levels, nausea and depression.

Q: My Mum was give Dexamethasone as part of her cancer treatment; the Doctor said she had to have it as it was a drug that treated cancer. Is that right?

A: People get confused about Dexamethasone because it is used with other drugs to treat cancer. On its own, according to the National Cancer Institute in the USA, there are no clinical trials to suggest that Dexamethasone has anticancer properties in its own right (1).

Q: Why is Dexamethasone used?

A: Dexamethasone is a corticosteroid and is approved for use as an anti-inflammatory agent. It was first used with combinations of IV drugs, such as FOLFOX or FOLFIRI when the four drugs given might cause damaging inflammation in the gut, even damaging the gut wall. Its use has broadened, so it is used now with 3 drugs, 2 drugs and even just one drug.

Q: Does Dexamethasone have other actions?

A: It is proven to lower the immune system, which can be useful in limiting allergic reactions to drugs. This is a second ‘approved usage’.

It has been used with CANCERactive patients to stimulate the appetite. This is not an ‘approved usage’ and, in one case, had disastrous effects.

Q: I’m worried - I’ve been told Dexamethasone puts up your blood sugar and encourages yeasts to grow in your body. Is that true?

A: An unfortunate side-effect is that it can increase your blood sugar levels in a dose-dependent way. Just a single dose is enough to put up your blood sugar (7).

Dexamethasone can also increase the risk of pathogens and especially make fungal infections worse (2). This is due to its inhibition of your immune system and the increase in blood sugar. At CANCERactive, Chris Woollams always encourages the simultaneous use of Yeast Killers such as Oregano oil.

Q: I was told Dexamethasone was perfectly safe in the hospital, but I hear Dexamethasone has lots of side-effects

A: Dexamethasone does has a lot more side-effects than even oncologists realise.

Ironically, it can cause nausea, stomach upset and stomach irritation.

It can cause headaches, dizziness, depression, anxiety, and insomnia.

It can affect a woman’s periods, increase hair growth, cause redness and acne, and in extreme cases cause vision problems, black stools, muscle weakness and a swollen face, legs or ankles, in which case you should consult a Doctor immediately (3).

In a study on mice, dexamethasone use was associated with a significant loss of diversity in the microbiome, and to changes in the liver/body ratio and spleen/body ratio. Dexamethasone also decreased the white cell count and body weight (4).

In a study on IBS, Dexamethasone was shown to reshape the microbiome, with an increase in bacteria such as Lactobacillus that are anti-inflammatory (5). Indeed researchers concluded that the bacteria rather than the drug may be the key mediators of inflammation!

Q: Are there occasions when Dexamethasone should not be used?

A: This is a difficult question to answer.

It probably should not be used if you already have high blood sugar or Diabetes.

There is research that says it gets in the way of immunotherapy drugs, specifically with Brain Cancer (6). Dexamethasone use was the strongest indicator of lowered survival. “We know that steroids have potential side effects, but our findings suggest that they also have detrimental effects in terms of diminishing the body’s immune response against a tumor,” said David Reardon, M.D., clinical director of Dana-Farber's Center for Neurooncology, who led the research.

Q: What cancers does Dexamethasone treat?

A: It has featured in clinical trials as part of a drugs package on various occasions, notably with blood and lymph cancers - Multiple Myeloma, Leukaemia and Lymphoma. However it does not appear to have any direct anti-cancer action in its own right according to the NCI.

Q: What other conditions is Dexamethasone used for?

A: Dexamethasone is also used alone or with other drugs to prevent or treat the following conditions, some of which are related to cancer or cancer treatment:

  • IBD - colitis, IBS
  • Anaemia
  • Drug hypersensitivity (allergic reactions)
  • Cerebral edema (fluid build-up in the brain) associated with brain tumours
  • Hypercalcemia (high blood levels of calcium)
  • Thrombocytopenia (low platelet levels)

Q: Is there a diet I should follow with Dexamethasone?

A: A potassium-rich, magnesium-rich, low sodium, low sugar diet would be best (that’s a Rainbow Diet). Some people simultaneously take Metformin off-label, or the herb Berberine, to reduce their blood sugar

Always take Dexamethasone with food.

The dose of Dexamethasone will be prescribed by the Doctor for the specific issues you face.

Q: My father was given Dexamethasone for his breathing problems. Does it work?

A: There is new research from the Lancet on this website showing it doesn't work for Dyspnea (breathing issues). The research even showed Dexamethasone can make matters worse.


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  1. National Cancer Institute - Dexamethasone

  2. Dexamethasone Promotes Fungal Infection By Inhibition of APC Activation with Beta-Glucans Via STAT-3 and NF-κb; Peter Brossart, Philipp Kottoff, Blood, Dec 2, 2016

  3. Medline - side-effects of Dexamethasone

  4. Shifts in the gut microbiota of mice in response to dexamethasone administration; Zhao H, Jiang X, Chu W. Int Microbiol, 2020 Nov;23(4):565-573.

  5. Using Corticosteroids to Reshape the Gut Microbiome: Implications for Inflammatory Bowel Diseases; Edmund Y Huang et al, Inflammatory Bowel Diseases, Volume 21, Issue 5, 1 May 2015, Pages 963–972

  6. Concurrent Dexamethasone Limits the Clinical Benefit of Immune Checkpoint Blockade in Glioblastoma; J Bryan Iorgulescu et al,  Clin Cancer Res, 2021 Jan 1;27(1):276-287. 

  7. Effect of single-dose dexamethasone on blood glucose concentration in patients undergoing craniotomy 



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