Adrenal Fatigue can be a real dilemma for thyroid patients in many ways and my belief is that this is why some doctors like to stay away from it and one of the ways they do this is by denying its existence.
Medical sources including the thyroid medication manufacturers warn that "untreated adrenal cortical insufficiency" (low cortisol) can be worsened by treating hypothyroidism with hormone replacement therapy, without first correcting it or treating them both simultaneously. What then becomes a question is how bad does the low cortisol have to be, to present a real problem? Certainly full blown adrenal insufficiency can present this problem but it only takes common sense to realize that severe adrenal fatigue or adrenal exhaustion can as well (low cortisol regardless of cause). Less severe adrenal fatigue many times will resolve when hypothyroidism is corrected because the low functioning thyroid causes everything, including the adrenals to operate low (slowed metabolism). When adrenal fatigue in hypothyroid patients isn't severe, it usually corrects on its own when the hypothyroidism is corrected.
Other patients aren't so fortunate and you can find their testimonials often on the web. They struggled with their adrenal fatigue worsening when they started thyroid hormone medication and continue to struggle with it as they continue their treatment. Some of them also have intermittent adrenal fatigue that is ingoing or chronic and onsets easily with stress or physical exertion, even while they are on optimal thyroid hormone therapy. I personally fit into that category and I had a variety of symptoms that worsened with the start of thyroid hormone medication. I feel it's possible that many of the patients, who report worsening symptoms for a while after starting thyroid medication for hypothyroidism, may very well be experiencing these adjustment symptoms as both the thyroid and adrenal hormones are trying to correct to normal levels. Those who seem to never reach a well adjusted state on thyroid hormone should have their adrenal hormones tested in my opinion.
In regard to cortisol steroids (corticosteroids) that replace low cortisol which include Prednisone and Cortef. I agree with sources that warn if a doctor is not highly skilled in administering these drugs for adrenal fatigue, they worsen it (adrenal suppression). True adrenal insufficiency is easier to treat in one sense because patients need full replacement as a lifelong treatment, while adrenal fatigue sufferers need less than full replacement and for short term. It's possible there is a dose of corticosteroid that is safe to treat adrenal fatigue with but medical research has yet to find it, so that it works for a large cross section of people, safely, with no adverse effects or risks.
If safe over-the-counter supplements can be tried first, this is a better way to treat adrenal fatigue in my opinion. A doctor is needed for corticosteroid treatment, if it needs to be administered as well for more severe adrenal insufficiency at a certain point. Helpful over-the-counter supplements for adrenal fatigue include the "B" vitamins, especially B-5, B-6 and B-12, vitamin C, licorice root extract (only as label-recommended and short term) and processed adrenal glandular supplements (usually beef/bovine source), using the same precautions as with licorice root. Some people report improvement while on herbal adrenal support supplements as well, including use of a supplement called "Adreset", made by the Metagenics Company. This company also makes a vitamin supplement for adrenal support called "Cortico-B5 & B6", which also contains magnesium and vitamin C in it. My pharmacist recommended these to me because they are pharmaceutical grade and they have helped with my adrenal fatigue a great deal. A company that makes a non-hormone adrenal glandular is Vitamin Research Product Company who offers their product called "CortiTrophin". Their company has Pharmacists and MDs behind research and development of their supplements and is why I believe they are more reputable than some of the other adrenal supplement manufacturers out there.
These are really the only options we have if we suffer adrenal fatigue because much of the medical community has this condition on a back shelf, until it becomes more widely accepted as a real illness.
Following is a quote from a PubMed published article entitled; STRESS-INDUCED HYPO-CORTISOLEMIA DIAGNOSED AS PSYCHIATRIC DISORDERS RESPONSIVE TO HYDROCORTISONE REPLACEMENT
Here is that quote:
"...cortisol deficiency is rarely taken into account in a medical or psychiatric work-up, so persons with mild to moderate cortisol insufficiency are for the most part relegated to receiving a psychiatric diagnosis when, in fact, the same disorder is represented."
(See link to this research article in "Related Links" area below.)