by Jim Stockigt MD FRACP FRCPA
Consultant Endocrinologist, Epworth and Alfred Hospitals, Melbourne,
Professor of Medicine, Monash University.
About a year ago, a young woman who had been well on standard replacement with Cortate for several years described some unexpected symptoms at her annual review visit. For the past few months she had noted unexpected weight gain of at least 5kg, roundness of the face and difficulty sleeping. She also described herself as emotionally “fragile” during this time. These symptoms were suggestive of Cushing’s syndrome, the exact opposite of adrenal insufficiency or Addison’s disease.
Review of her medication, newly prescribed about 3 months earlier, showed that she had been taking prednisolone (Solone) 25 mg am, 12.5 mg pm, instead of that dosage of Cortate.
It is important for people who take continuing glucocorticoid replacement to know about this potential mishap, which occurs from time to time either as prescribing or dispensing error and will, if continued, result in chronic over-dosage that can be quite disabling. If picked up early, no harm will occur, but if the error is missed, the effects on skin, bones, appearance, psychological state and blood glucose will be serious. Most, but not all medical practitioners and pharmacists are aware of this important difference. The error can be easily made by those who are not very familiar with these medications because Cortate and Solone are both dispensed in 5 & 25 mg tablet sizes. (High doses of Solone are used for anti-inflammatory effect, or after transplantation).
If you believe that this error has occurred, do not cease the medication abruptly. A few days of excessive dosage are far less harmful than the effects of acute Addisonian crisis! Continue your medication, seek early advice and try to make sure that the same person does not make the same mistake again.
The approximate equivalent doses of various “cortisone” preparations are as follows, as summarised in Therapeutic Guidelines, a source of medication information that is regularly reviewed by medical specialists and revised if necessary. Current product and consumer medicine information give no guidelines about dose equivalence. If there is difficulty with supply of a particular preparation, as occurred recently with Hysone, safe substitution can be made using these conversion factors.
|Medication & tablet size||Equivalent dose, mg|
|Hydrocortisone (Hysone, 4 & 20mg)||20|
|Cortisone Acetate (Cortate, 5 & 25mg)>||25|
|Prednisone/Prednisolone (Solone etc., 1, 5 & 25mg)||5|
|Dexamethasone (Dexmethsone, 0.5 & 4mg)||0.5|
Prednisolone and prednisone (5 mg tablets!) are quite satisfactory for adrenal replacement, in the usual dose of about 5 mg am, 2.5 mg pm. A higher dose of Florinef may be required if prednisolone rather than Cortate or Hysone is used for replacement. Another glucocorticoid, dexamethasone is even more potent, but is rarely used for replacement, in a dose of less than 1 mg per day.
The message is clear! Know your medications and check the label, no-one is infallible.