|
Most patients with pemphigus and pemphigoid take prednisone at some time to control their disease. Besides the effect to suppress the immune system, there are many other effects prednisone and other similar glucocorticoids have on our bodies. One that is very interesting is the way prednisone affects the bodys own production of cortisol. Cortisol is a glucocorticoid our body produces, and is necessary to live. It is made in the cortex of the adrenal gland which is located above our kidneys.
 |
| Dr. Tenner |
There is a complex mechanism that the body uses to regulate the amount of cortisol that is produced. It relates to a feedback system called the hypothalamic-pituitary-adrenal axis. Normally the level of cortisol in the blood is determined by such things as circadian rhythm (cortisol is highest in the morning), stress (which increases the level of cortisol) and the way the blood cortisol level affects the hypothalamus (part of the brain) to produce a hormone called corticotropin-releasing hormone (CRH).
CRH affects the pituitary gland by causing it to release a hormone called adrenocorticotropin (ACTH) into the blood, which causes the adrenal cortex to release cortisol. This interplay in the hypothalamic-pituitary-adrenal axis is what determines the cortisol level in the blood.
When people take prednisone it is sensed by the hypothalamus, which makes less CRH, which in turn affects the pituitary, which leads to the adrenal glands making less or no cortisol. If the adrenal glands are turned off long enough there is a possibility they may not restart making cortisol when it is needed.
One of the reasons many doctors like to get patients on every other day treatment with prednisone is the hope that on the off day for prednisone the adrenals will be stimulated to produce cortisol; in other words to keep working. It is only when a person is getting below about 7.5 mg of prednisone per day (which is comparable to the amount the adrenals normally produce) that someone would have to worry that his adrenals might not start up and produce the cortisol he needs to stay well.
|
To test for this possibility, plasma cortisol levels can be determined by drawing a blood sample in the morning before any prednisone is taken. If low, it indicates the adrenals are not fully working. Sometimes they do not start up (called secondary adrenocortical insufficiency) and the person has to always be on prednisone; other times it just means giving them more time to recover.
Even when off all prednisone for up to a year, in times of stress when the body needs extra cortisol to deal with a severe illness, injury or surgery, this inability to make the needed amount of cortisol by the adrenal glands could be a problem unless extra prednisone-like medication is given by doctors to help the body get through the stressful time.
The symptoms of low cortisol i.e. adrenal insufficiency include weakness, fatigue, weight loss, nausea, loss of appetite, vomiting, abdominal pain, and fainting. Anyone who has been on prednisone and has tapered the dose is aware of how this can affect how one feels. If the dose of prednisone you are on is low and these symptoms become a problem, talk to your doctor about having a plasma cortisol test done and adjusting the prednisone dosage.
To minimize the symptoms associated with lowering the dose of prednisone, it is especially important to do this tapering slowly when the dose gets below 20 mg per day. Many doctors suggest 1 or 2 mg every few weeks. This allows the body time to adjust to the lower levels, and hopefully when low enough the adrenal glands will start producing their own cortisol in sufficient amounts to avoid any problems.
It is also a reason that every patient should talk with their doctors when lowering prednisone and not do it on their own.
Originall published in the February 2004 issue of Recovery.
|
