If you have been diagnosed as hypothyroid, or as suffering from Hashimoto’s autoimmune thyroiditis, you will be prescribed thyroxine (Levothyroxine) by your physician.
However, if you are suffering from adrenal insufficiency, the thyroxine tablets cannot work as they should. Worse, they may precipitate an acute adrenal crisis.
How Should Levothyroxine Work?
Most of the Levothyroxine dose is absorbed from the small intestine. It is then converted into the active form of the hormone, T3, mainly by the liver, through a process of de-iodination. The T3 hormone acts to energize the whole body, while also affecting all the other parts of the metabolic loop, such as the TRH and TSH levels.
What are the Adrenal Glands?
The adrenals’ role is to respond to stress messages from the brain by releasing steroid hormones. Cortisol is the main representative of the glucocorticoid steroids produced by the adrenals. This vital hormone is famous for helping the body deal with stress and inflammation, but it is also essential for the correct functioning of the immune system, and the body’s use of carbohydrates, fats, and proteins.
Adrenal insufficiency can be mistaken for hypothyroidism, as the symptoms are very similar. See Adrenal Insufficiency.
What Happens if I Take Thyroxine with Adrenal Problems?
Even if the adrenal insufficiency is slight, it will adversely affect thyroid conversion, tissue uptake, and thyroid response.
If the T4–T3 conversion doesn’t happen as it should, the body can become toxic through unused T4. If it is converted, but the T3 cannot enter the cell walls due to adrenal insufficiency, the T3 cannot be used, and may reach toxic levels. In either case, T4 and TSH blood tests will appear normal, but the patient may feel really unwell. (6) If a physician raises the thyroxine dose in this scenario, the situation worsens still further.
The reaction varies with degrees of adrenal insufficiency. Symptoms may include: a sudden feeling of exhaustion, nausea, headache, inability to concentrate, trembling, muscle weakness, loss of peripheral circulation leading to numbness, lack of muscle control, giddiness, slurred speech, and cognitive impairment.
And as the literature included with this drug points out, the result can be extremely serious in anyone suffering from severe adrenal insufficiency:
“Levothyroxine is contraindicated in patients with uncorrected adrenal insufficiency since thyroid hormones may precipitate an acute adrenal crisis by increasing the metabolic clearance of glucocorticoids [a too-rapid withdrawal of cortisol]. Patients known to suffer from adrenal insufficiency should therefore be treated with replacement glucocorticoids before starting any Levothyroxine sodium treatment. Failure to do so may precipitate an acute adrenal crisis when thyroid hormone therapy is initiated.(2)
Adrenal insufficiency must always be addressed before starting any thyroxine treatment.
What is an Acute Adrenal Crisis?
Medline puts it like this: “Acute adrenal crisis is a life-threatening condition that occurs when there is not enough cortisol, a hormone produced by the adrenal glands.”
This should not be confused with Addison’s Disease, which is a long-term form of adrenal insufficiency. In contrast, an acute adrenal crisis is likely to manifest with vomiting, abdominal pain, and hypovolemic shock.
Could I have an Adrenal Problem?
Primary adrenal insufficiency occurs when the adrenal glands fail to release adequate amounts of their hormones to meet physiologic needs – and infiltrative or autoimmune disorders are the most common cause. Adrenal exhaustion can also be caused by severe chronic illness. (5)
Chronic autoimmune thyroiditis – Hashimoto’s Disease – is known to occur with other autoimmune disorders, such as adrenal insufficiency, pernicious anemia, and insulin-dependent diabetes mellitus. This is known as autoimmune polyglandular syndrome.
Low cortisol levels can be caused by drug therapies with androgens or the anti-seizure medication phenytoin.
Read more:
Why Isn't My Thyroxine Working?
The Truth About Hashimoto's Disease
Notes
- Deiodinases: implications of the local control of thyroid hormone action”, A.C. Bianco and B.W. Kim, October 2, 2006. Endocrinology Division of Endocrinology, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA
- FDA information, listed by MOVA Pharmaceutical Corporation, on Drugs.com, 08/2008. LINK: http://www.drugs.com/pro/levothyroxine.html
- “Immune system, effects on the endocrine system”, Chapter 29 - Jason A. Berner, M.D., Dimitris A. Papanicolaou, M.D.; March 11, 2003
- Abbas, et al., 1997)
- “Adrenal Crisis”; Lisa Kirkland, MD, FACP, CNSP, MSHA, Assistant Professor, Department of Internal Medicine, Division of General Internal Medicine, Mayo Clinic; ANW Intensivists, Abbott Northwestern Hospital; Dec 18, 2007
- “Your Thyroid and How to keep it Healthy”, by Dr Durrant-Peatfield; Hammersmith Press, 2006.
Sarah Tomley - Sarah is an editor and writer who has been working in the UK publishing industry for over 18 years. She has an honours degree in ...
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