Stress dose steroids are used in numerous scenarios including adrenal insufficiency, critical care, and the perioperative period. What’s important to understand is that the peak physiologic production of steroid (cortisol) is roughly the equivalent of 300 mg of hydrocortisone a day under maximum stress. Any exogenous steroids which exceed this dose are supra-physiologic. Often times you’ll find patients on crazy steroid regimens which, when converted to hydrocortisone, are 10-fold higher than what the body can even make under the most stressful circumstances!
If you’re using these super high, pharmacologic levels, you can actually wean down aggressively to 300 mg of hydrocortisone (100 mg q8h) without worrying about adrenal insufficiency, since this is what your body would normally produce under stress. The caveat to remain above this threshold is if you’re treating another condition like a COPD exacerbation or rheumatologic process.
Now as you continue weaning, how do you assess whether or not the patient’s adrenal glands are picking up the slack of producing endogenous cortisol? In other words, are the adrenals still working or completely shot? Give a patient their AM dose of steroids, then stop all steroids till the following morning. At that point, perform an ACTH (cosyntropin) stimulation test and assess their results. If their cortisol level rises appropriately, you can rest assured the adrenals are functioning normally and can continue weaning aggressively.