A question many people have is: “How long does prednisone stay in your system?”

It might seem simple, since prednisone‘s half-life is 2-3 hours, but there’s a nuanced answer to that question I explain in this video and article below.

What I show you can help you know when to take prednisone, how often to take it, and what to do about certain side effects.

Watch now!

How Long Does Prednisone Stay in Your System? Video Transcript

Transcription autogenerated from the video above so some errors are possible

weight: 400;”>How long does Prednisone stay in your system? You might be wondering this amazing drug, it’s you’re taking it and you wanna know, well, if I took it, how long does it stay in my system? How long does it stay and do the good thing it’s supposed to be doing? I am Dr. Megan, your Prednisone Pharmacist and I have a surprising answer to this question that has a lot to do with our genes.

So stay to the end to understand exactly what an interesting way our body created that really answers this question. So if you ask how long does prednisone stay in your system, you might really be asking how long until it’s gone, how long until prednisone is out of my system. If you want to know exactly how long it takes prednisone to get out of the system, that has something to do with what’s called a half-life or how long it takes for half of a drug to get out of your body.

If you took prednisone 20 milligrams at 8:00 AM (which is when you’re supposed to take it; sometime before 9:00 AM), then about two to three hours later, depending on what your body’s half-life is, half of it would be gone and you’d have the equivalent of 10 milligrams, but is two to three hours really the proper half-life, maybe one textbook.

I’ve got this giant big fat heavy textbook that says that the half-life is 60 minutes. But other things like the most recent drug studies that were submitted to the FDA for the new drug Rayos showed that prednisone has a half-life of two to three hours. 

Anywhere between 60 minutes and four hours could be the range of prednisone’s half-life.

Factors Affecting How Long Prednisone Stays in Your System

How long prednisone stays in your system is actually dependent on things that you may or may not be able to control.

Food

First of all, what you eat may have something to do with the side effects. When they studied Rayos, this new drug of prednisone where they delayed the release, if it was eaten with a fat-heavy meal, it delayed how long prednisone took to get out of the system and how high of a peak you hit. 

So maybe Prednisone itself does that. We don’t know for sure whether the common, immediate-release, cheap version of prednisone has that exact effect. 

However, recent research showed that it didn’t matter whether or not prednisolone was taken with food. The authors of this scientific poster concluded that:

Food had little effect on the absorption of prednisolone when given either before or after breakfast.

Choudhury SM, Williams EL, Tan TM. The pharmacokinetic profile of prednisolone is not affected by ingestion of food – how should patients be advised? Endocrine Abstracts (2016) 44 P23 | DOI: 10.1530/endoabs.44.P23

Keep in mind that this is prednisOLONE, not prednisONE, so we don’t know for sure whether it’s true for both. (Read on to understand the difference between prednisone and prednisolone).

Your Genes May Affect Your Side Effects

This chart showing that the amount of time it takes you to get rid of prednisone from your body may have an effect on your side effects. It might be a a factor in in the amount of side effects you have.

They showed that those who were able to clear prednisone faster from their bodies had less side effects and those who cleared it slower had more side effects.

Your size

Your body surface area (BSA) can be a factor in your ability to get prednisone out of your system. The BSA is the amount of meters (m2) squared and that has to do with your height and your weight. 

Age

It may take a different amount of time for somebody who is a child versus an adult. 

Fat Distribution

It may take a different amount of time for somebody who is thin and doesn’t have a lot of body fat versus somebody who has more body fat.

Kidney & Liver Function

If you have kidney or liver problems, you may have a different amount of time for your body to get rid of prednisone because of how prednisone is broken down.

How Prednisone is Metabolized (Breaks Down)

So first, if you take prednisone, it is changed into prednisolone in your liver by an enzyme.  Prednisone itself actually doesn’t do anything until it becomes that Prednisolone molecule. 

Prednisolone is an active drug and it can actually do things in your body affecting your naturally occurring hormone in your body called cortisol. And cortisol is what it’s mimicking and doing those things.

When your body has cortisol floating around it in the blood, there’s a little bit that’s floating around in the blood somewhere around 5% that’s free and about 95% is stuck in the blood to a protein called the cortisol binding globulin. Most cortisol isn’t actually able to do anything. It’s just stuck on these binding globulins floating around, floating around. And that little tiny 5% is what actually does the effects in your body.

And so that floats around and it reaches a cell and there’s a cell membrane and the cortisol molecule gets to go through the cell and into where the nucleus is and the nucleus has our genes, our DNA is in there and it goes in there and it is able to read the genes. Prednisone and  cortisol affect two thirds of the genes in our body according to the textbook “Congenital Adrenal Hyperplasia: A Comprehensive Guide.”

“Cortisol regulates over two thirds of human genes.”

Since prednisone mimics cortisol…

2/3 of our genes are affected by prednisone!

Two thirds of the DNA of our body can be either turned on or turned off or a protein is made because of what cortisol is doing in our bodies. So it’s a really big deal if we take a steroid hormone–prednisone, hydrocortisone, dexamethasone, methylprednisolone–any of these glucocorticoids have a really big effect on our bodies. It’s not just an the inflammation, it’s not just the immune system that’s affected. 

Two thirds of genes are affected. Prednisone’s effects can stay in your system because it’s not just the prednisone molecule that matters. 

Prednisone is Like a Tornado

If you think that’s really complicated scientifically, let me change it to a more simple, easier to understand analogy. Let’s pretend that prednisone is a tornado and you have a building that you want to knock over.

It’s falling apart, it’s diseased, and the building represents your actual disease. Whatever problem you’re taking prednisone for is this building that you want knocked over. So a tornado comes through town and knocks over the building, but tornadoes are not remotely precise and can be too big or last too long or whatever and cause a lot more damage than just knocking over the building we wanted knocked over,

Right? Instead of just that building, we are losing the landscaping around the building. We’re losing the light poles, we’re losing maybe the street itself, the cars parked out front, maybe all the buildings around it, maybe the entire town is destroyed because of the tornado passing through. And that’s what prednisone is like. It does this amazing good thing.

It destroys that building, the inflammation that is causing you to feel horrible, but it has lots of other effects. And even though the tornado passed through town in 30 seconds, three minutes, 10 minutes, whatever it was, its effects don’t just go away in three minutes. The molecule of prednisone is that tornado that passed through town.

It’s gone in somewhere around 18 hours after you took it, depending on your liver, your kidney, your age, your gene, all of those things. But that destruction of the town doesn’t just go away.

Somebody has to reinstall the landscaping. It has to build that street back up. Somebody has to replace the cars and the buildings that were also destroyed, right?

That takes longer. So prednisone stays in your system somewhere around 18 hours, but it could have effects for much longer.

Let’s first talk about the good effects of prednisone. So according to this textbook, it says it has this awesome chart. It says that the active drug that prednisone becomes Prednisolone has a half-life in the blood of two to three hours. And we already know that and that’s how we decide that half-life is. Basically after 5.5 half lives, the drug is essentially gone from the body.

So it started out at 20 milligrams. If you took this exact pill at 8:00 AM and then by 11:00 AM we’re at half of that, we’re at 10 milligrams by 1:00 PM or no 2:00 PM that’s three hours later. We’re at the equivalent of five milligrams by 5:00 PM We’re at the equivalent of 2.5 milligrams by 8:00 PM we’re at the equivalent of whatever half of 1.25 milligrams is. And after 18 hours, the amount is so small of the actual prednisone molecule that you can’t detect it, it’s it’s gone.

It was it’s 99% gone and essentially no longer there.

Duration of Glucocorticoid Action of Prednisolone

But that’s not all that there is that matters. There’s also the duration of glucocorticoid action as seen in the table above in the “prednisolone” column. So as a glucocorticoid, as a drug that’s affecting your glucose metabolism, your fat and sugar metabolism, that is eight hours. So you take prednisone at 8:00 AM and it’s still affecting your blood glucose for somewhere around eight hours.

Duration of Inflammatory Action of Prednisolone

Then there’s also the duration of inflammatory action, and that is between 12 and 36 hours. So those changes your body made through the DNA being turned on and turned off, the proteins that were made because of the cortisol affecting your genes causes anti anti-inflammatory activity that can last for 36 hours. So while the half-life was only 18 hours, the drug molecule’s gone from your body after 18 hours, but another 18 hours later, at 36 hours, there’s still anti-inflammatory activity.

Isn’t that amazing? So yes, prednisone only stayed in your system for 18 hours, but its effect on the glucocorticoid anti-inflammatory lasts longer. It goes to up to 36 hours, and that’s for Prednisolone. We don’t even actually have precise data for prednisone. I searched high and wide, I couldn’t find it. So for 36 hours you can have this in anti-inflammatory activity.

Time to Peak Level of Prednisolone

Then the time to peak level for Prednisolone is three to four hours. So you take the pill, you swallow it, and it takes some time to be absorbed, broken down, and to actually get into your blood. It goes from your mouth down to your gut, to your liver, to your blood, and for Prednisolone takes three to four hours. And then after 18, then it’s finally gone.

Side Effects Last Longer Than Prednisone’s Half Life

But what’s also interesting is the side effects have a different time period. So when is prednisone gone from your body? Well, it’s gone after 18 hours. But the duration of when growth suppression happens–if a child takes prednisone and it can affect their ability to grow–that lasts five hours.

If they take another drug that’s like prednisone called dexamethasone, its growth suppressing effect is 80 hours! Days are affected by the growth suppressing effect.

Growth suppression just one side effect of steroids. Then there are other side effects such as on your metabolism. Those changes, the turning on and off of genes doesn’t just go away after those 18 hours. It takes time to recover, to heal. Then they’ve done studies on that dexamethasone sister drug to prednisone, and they showed that one dose, in perfectly healthy young men who didn’t need it–just to see what happens to a body after taking it–it showed that they had effects on a majority of the metabolites–they tested hundreds of metabolites and everything from the blood cholesterol to the blood glucose to all the little pieces in between–the majority of them were affected for at least three days after taking it and probably longer. But they didn’t have enough money to test much later than that. They were affected by side effects for days–much longer than the half-life itself.

Frequently Asked Questions about How Long Does Prednisone Stay in Your System:

Here are some other questions you might have related to how long does Prednisone stay in your system.

How long does Prednisone stay in my system: How often should I take Prednisone?

Well, our bodies secrete cortisol, that naturally occurring hormone, every day in this rhythm, this beautiful rhythm, and it’s related as a circadian rhythm with melatonin and it’s highest early in the morning and it gets lower around 4:00 PM between 4:00 PM and 2:00 AM is the lowest that it ever gets, and so it’s high and then low and prednisone mimics that pretty closely. But it’s helpful to know because how long it stays in your system directly affects side effects.

Like for example, if you take prednisone at night and you’re getting that burst of cortisol at night instead of in the morning, that’s a wakeful hormone that’s causing blood sugar to be released and you don’t want that when you’re trying to fall asleep. And so you don’t take prednisone at night generally unless your doctor tells you to.

Because of that, it makes a lot more sense to take prednisone at the same time your body releases cortisol because then you’re helping your body do what it’s already doing instead of fighting against it and making it harder to sleep, which is why insomnia is one of the number one side effects to prednisone. So when we help mimic our body, that can counteract side effects.

How long does Prednisone stay in your system: When Should I Take Prednisone?

Another thing you might be wondering based on how long does Prednisone stay in your system: When Should I Take Prednisone? So that affects what time you take it and how often you take it. You could take it usually generally once a day, but rarely, very rarely people take prednisone twice a day and then also rarely it’s every other day because we’re hoping that your body is able to turn back on the hypothalamic pituitary adrenal system. This, this system that is what’s running your cortisol, your stress response, that it’s giving it a chance to recover. And so if some doctors prescribe it every other day, that’s a possibility.

It’s not. It’s common as it used to be. It used to be this really cool strategy. It hasn’t necessarily panned out, but some doctors do it. Hopefully it’s working for you. But so you can take prednisone that often because of how long prednisone stays in your system, and then it’s related to how long it takes prednisone to work.

Prednisone takes somewhere between 30 minutes to two to three hours to work, depending on your ability to break it down from prednisone to Prednisolone and have that active metabolite get absorbed into your bloodstream and have not too much of it floating around, stuck to the proteins, but as free.

Read more about How long does Prednisone take to work?

How long can you stay on prednisone?

You can stay on prednisone as long as your doctor prescribes it.

But how long is prednisone safe? Basically, prednisone is not a safe drug to be on for any period of time. One dose is long enough to cause side effects. So how long can you stay on prednisone? Any dose is going to cause a side effect. 

So as long as the balance of risks and benefits are in your favor, for example, as long as you are taking prednisone and it’s still doing good things for you, you’re still having pain relief or able to breathe or whatever you’re taking it for, that good thing is happening and you’re not having too many side effects. If that’s the balance, then continue taking it.

But once the good stuff isn’t working as well or the side effects are getting terrible, then you should definitely talk to your doctor about getting off the prednisone because you don’t wanna stay on prednisone any longer than you absolutely must. We always wanna go for the lowest dose for the shortest period of time possible.

When it comes to Prednisone and other steroids, we do not want to expose our body to one extra milligram if we absolutely have to. So how long can you stay on it? As long as you and your doctor find that it is in the right balance of benefits and risks, you should definitely talk to your doctor about it and then that can help you to decide the precise balance of those benefits and risks for you.

How long does Prednisone stay in your system after taking it for seven (7) days?

Another question you might have is if you’ve been taking Prednisone for a certain period of time, how long does it stay in your system after that? So a specific question you might have is, if I took prednisone for seven days, how long does Prednisone stay in your system after taking it for seven days? Prednisone is it doesn’t accumulate or collect in your body.

It’s not like if you take it on day one, then you have a little bit, and day two you have a little bit more, and day three, you have a little bit more that’s building up. Prednisone is completely gone after one day. And so it’s pretty much the same if you took it for one day or if you took it for seven days.

If you took it for seven weeks, it’s still 18 hours until it’s out of your system. But back to my tornado analogy above, it’s the drug itself is gone after 18 hours, but its effects do not go away immediately. They all range and have their own recovery time period. And so if you’re wondering how to help your body recover, how to support your body while you’re taking prednisone, so that when prednisone is no longer staying in your system, you know exactly what to do to counteract the side effects. To recover, to feel like yourself again, you need to download my Prednisone checklist.

On it, I have 15 of the top side effects of prednisone and what you can do to counteract those side effects, plus my top 25 tips for exactly what to do while on prednisone. To feel your very best, just fill out the form above to download your own Prednisone Checklist.

References

Puckett Y, Gabbar A, Bokhari AA. Prednisone. [Updated 2023 Jul 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024