I think we've all been told that we could take prednisone instead of hydrocortisone to manage our adrenal insufficiency. "It lasts longer! You don't have to take it as often! You can take less!" Yes, Yes. No. Sure prednisone lasts longer and you don't have to take a longer acting steroid as often but do you know why your doctor is telling you to take it as opposed to hydrocortisone? Because he thinks you're in capable of taking hydrocortisone as often as you would need to so that you have proper steroid coverage and you'll end up in the ER.
For the record, there are a few people for whom prednisone will work better than hydrocortisone. They may actually be noncompliant and take ownership of it. They may have other inflammatory conditions that are helped by pred's long lasting effects. Physiologically, it just may work better for a very small portion of people. If you are one of these people, go for it.
Why is prednisone a problem? It has a much longer half-life than hydrocortisone. Hydrocortisone is bioidentical to cortisone, the hormone that the adrenals are supposed to release. Hydrocortisone is converted to cortisol in the liver. Cortisol in is a hormone that interacts with multiple other hormones in the body. The ebb and flow of it helps release hormones, metabolize some as well as keep your blood pressure and blood sugar up. Cortisol has a much shorter half-life than prednisone. When you mess with half-lives, you're messing with the circadian rhythm. When you mess with the circadian rhythm, how can you expect to optimize your health? You can't.
Prednisone is also undetectable in a cortisol blood test. Its chemical structure is different than cortisol. Some doctors loooooove to test cortisol but forget that prednisone is undetectable in the blood draw. They are puzzled at why an 8 am cortisol test would be so low when a patient had recently taken his or her daily dose of prednisone before the test. They jump to the conclusion that the patient is not taking her prednisone as specified or is not on enough steroid. In the case of the latter, the patient is then instructed to take more steroid (when it might not be justified by symptoms) which leads to over replacement, insomnia, ill health and a greater possibility of osteoporosis and type two diabetes. Too much steroid of any kind can cause the problems listed.
Prednisone is so long acting that it does not ebb and flow the way hydrocortisone does. You might think that's great. It's not. Your body is designed to have ebbs and flows. For example if the steroid in your blood is not low at night when you are sleeping, growth hormone will not be released and you will have insomnia. When growth hormone is not released consistently, you will be fatter, more fatigued, have less sex drive and less muscle mass. None of those things contribute to optimal health. This is just one example of how one hormone is affected by steroids. There are many, many others.
Prednisone has little to no mineralocorticoid properties. Mineralocorticoid properties help you retain sodium. If you are in the hospital with a knee replacement surgery, on large doses of hydrocortisone (which has mineralocorticoid properties), have high sodium, low potassium and high blood pressure, prednisone is probably a good alternative to hydrocortisone for a short time. On a day to day basis, you're probably better off with the hormone Mother Nature intended for you, cortisol. A little mineralocorticoid goes a long way to helping you maintain your sodium potassium balance. Often, if a doctor cares so little about a patient's quality of life that he prescribes prednisone, he's often uneducated about how to evaluate a patient's mineralocorticoid status (renin, electrolytes, orthostatic blood pressure reading). If someone has low sodium (also called hyponatremia) constantly, osteoporosis will ensue. Evaluation of a patient's need for Florinef (the mineralocorticoid of choice) is vital regardless of whether the patient is primary or secondary so that hyponatremia can be avoided.
Taking less prednisone than hydrocortisone is just a weird concept. 5 mg of pred is equivalent to about 20-25 mg of hydrocortisone but the predinsone is more potent at that dose. I guess if you are a math person and lower numbers are better than higher ones, pred might be for you. What I'm saying is that the number does not matter so taking "less" of a more potent drug and "more" of a less potent drug is just a silly concept for a doctor to present to a patient. What matters is that a patient uses the lowest possible dose of a steroid while avoiding under replacement symptoms.
So, let's review. Prednisone can mess with your circadian rhythm,release of hormones and metabolism of other hormones. Prednisone has no mineralocorticoid properties. Sure, you take smaller number of milligrams of it but you should be taking an amount that's similar to your hydrocortisone dose. To me, it does not seem worth it to take prednisone once a day and have it last for only 8 - 12 hours from the time you take it so that you can be a "compliant" patient that feels like shit.
For you, prednisone might work. If so, that's cool. If you are saying to yourself, "I feel fatigued all the time, I'm gaining weight inappropriately, my blood pressure stinks, my blood sugar is through the roof, I sleep poorly and have terrible muscle mass" you might consider switching to an equivalent amount of hydrocortisone that's taken physiologically and see if it works differently or better for you. If you go to your doctor and ask to be switched from prednisone to hydrocortisone, bring the conversion calculator with you! It's amazing how often doctors switch someone from 6 mg (equivalent to 24-30 mg of hydrocortisone depending upon the calculator) of prednisone to 15 mg of hydrocortisone for no reason other than that's what they decided. There is no logic to cutting someone's steroid dose in half and thinking that the experiment didn't work. The doctor is setting you up to fail and feel miserable. Take an equivalent dose when you switch. You can always taper the dose down slowly over the course of time if that's an issue but start at an equivalent dose. You will need to try the hydrocortisone for about two weeks to get yourself into a rhythm and comfortable with the dosing. Don't do it for one day and say it doesn't work.
If prednisone is working great for you, terrific. No need to comment and tell me how wrong I am about all of this. I am happy for you! For most people, hydrocortisone taken physiologically is the best choice. If you are on prednisone and it's not working well for you, please consider discussing changing your steroid to hydrocortisone. You deserve to live the best life possible. When you have adrenal insufficiency, living the best life possible starts with hydrocortisone and physiological dosing.