How long does prednisone stay in your system – Urine, Sweat, Hair follicle, Breastmilk and bloodstream

What is prednisone used for? How prednisone affects the body?

Prednisone is a synthetic corticosteroid drug which is metabolized by the liver into its active metabolite, prednisolone. It is used in the treatment of skin conditions such as psoriasis, allergic dermatitis and eczema.

It is also used in the management of respiratory conditions such as asthma and status asthmaticus. The therapeutic effect of prednisolone is that it is immunosuppressive and anti- inflammatory. Thus, it is used in the management of autoimmune conditions as well as inflammatory conditions.

The use of prednisolone, like other corticosteroids, should be under the supervision of a medical practitioner. The effect of sudden cessation from taking the drug has serious consequences on the individuals’ health and it is, therefore, recommended that cessation should be under the supervision of a medical practitioner.

How long does prednisone stay in your system

The active metabolite of prednisone, prednisolone has a half- life of 2 to 4 hours. This means that it takes about 2 to 4 hours for 50% of the drug ingested to be excreted from the body. Several factors influence the rate at which the drug is cleared from the system. These factors are general, in the sense that they influence the excretion of any other drugs.

The excretion routes of prednisolone include urine, sweat, hair follicle, breastmilk and bloodstream. The dosage of prednisone taken determines the elimination timeframe for its excretion. Apart from dosage, individual factors such as body weight, urinary pH and diet will also influence the rate at which the drug is excreted from the body.

How long does it take for prednisone to leave your Urine, Sweat, Hair follicle, Breastmilk and bloodstream

Clearance of prednisone from the system

The active metabolite of prednisone, prednisolone, has an elimination half- life of 3 to 4 hours. This means that it will take approximately 16 to 22 hours for the drug to be completely excreted from the system, after ingestion of the last dose.

However, elimination of the drug can take longer in cases of ingestion of larger doses, chronic users of the drug, as well as hepatic impairment. Therefore, in some cases, clearance of the drug can take up to a week, depending on the factors that will affect its clearance from the system. The elimination half- life is 3 to 4 hours. This means that it takes 3 to 4 hours for 50% of the drug to be eliminated from the system.

Total elimination of the drug takes 16 to 22 hours. The variation in clearance rate of the drug is dependent on the influence of the individual variables such as age, urinary pH, body mass, height and frequency of hydration. Therefore, clear cut clearance rate is not available because different individuals will eliminate the drug at varying rates.

Peak effects of prednisolone can be observed within 1 to 2 hours after ingestion. The plasma elimination half- life is 1 hour but the biological half- life can go up to 18 to 36 hours. Generally, corticosteroids are distributed in blood and urine, with traces of the drug being found in breastmilk and in the fetal circulation, because of its ability to cross the fetal- placental unit.

Several drug tests are used to determine the amount of prednisone left in the body after ingestion. These tests can also be used to determine when the last dose of the drug was taken, for example the hair test. The urine test can detect amounts of prednisone lingering in the system.

The amount of prednisone detectable in the bloodstream is insignificant, as is the same with the saliva. The hair follicle test produces non remarkable results, making the urinary test, the most efficient and reliable way of detecting prednisone.

Generally, the elimination half- life of all forms of prednisone takes about 2 to 3 hours. This implies that in a healthy individual with healthy renal function, it will take 2 to 3 hours for 50% of the ingested drug to be excreted. This means that it will take approximately 11 to 16.5 hours for the drug to be completely eliminated from the system.

However, there is a variation of the elimination half- life which is influenced by the individual factors such as age, frequency of hydration and dosage taken. For example, an individual who frequently hydrates himself will excrete the drug at a much faster rate. Therefore, the total elimination time of prednisone can even go up to 20 hours.

Factors that influence clearance of Prednisone

The complete elimination of prednisone from your body takes about 16 to 22 hours. However, certain factors can influence this elimination time. These factors include individual factors such as age, body weight, urinary pH, metabolic rate and dietary intake. The other factor is dosage and duration of taking the drug.

The younger patients are able to excrete prednisone much faster due to the efficiency of the kidneys in performing their function of excretion. Conversely, elderly patients have impaired renal function which is associated with aging, meaning that the clearance rate will be low, thus it will take over 24 hours for the drug to be completely eliminated from the system.

The urinary pH of an individual also influences the rate of clearance of prednisone. The more acidic the urinary pH is, the faster the urinary excretion rate of prednisone will be. A person taking a larger dosage of prednisone will take longer to have it completely eliminated from their system. This is because the larger the dosage, the longer it takes for the drug to be absorbed into the system.

Therefore, the metabolism will also be delayed and so will the excretion of the drug. It has also been reported that patients that take prednisone with food tend to have a much slower clearance of the drug. This happens because food delays the absorption of the drug from the gastrointestinal tract (GIT). It can take up to 12 hours for the drug to get absorbed by the GIT in such a case. This results in delayed clearance of the drug from the body.

Drugs that induce the activation of the enzyme responsible for the metabolism of prednisone will enhance its elimination from the system. The enzyme responsible for catalyzing the reaction that eventually metabolizes prednisone into prednisolone is known as CYP3A4. Antifungal drugs such as itraconazole and ketoconazole (azoles), as well as certain antibiotics such as chloramphenicol are inducers of this enzyme. This means that if you are taking these inducers, the elimination of the prednisolone will be much faster because it will be metabolized faster due to enhanced enzymatic activity.

Conversely, ingestion of CYP3A4 inhibitors will slow the clearance of prednisolone from the system. CYP3A4 inhibitors include the anti- hypertensive drug, Nifedipine while foods that inhibit activity of the enzyme include pomegranate and grapefruit. Evidently, it is important that you inform your doctor of any drugs that you are taking as they can influence the effective circulation of prednisone in your system.

The time that the last dosage of the prednisone is ingested influences it excretion rate. In cases where the drug is ingested before bedtime, it will take longer to get excreted because during sleep, metabolic rate is slowed down, therefore, the metabolism of prednisone will be slowed down as compared to when it is ingested during daytime. Conversely, when the drug is ingested during day time, metabolic rate is at its peak, therefore, excretion of the drug is much faster.

In renal impairment, the excretion efficiency of the kidneys is compromised. This means that the kidneys excrete the toxins at a much slower rate than when in their normal healthy state. The metabolic rate also influences the rate at which prednisolone is excreted from the body. This means that the higher the metabolic rate, the faster that a drug is converted into its metabolites. Therefore, the excretion rate will be much faster than in an individual with a slow metabolic rate.

Patients that have been taking larger doses of prednisone usually have longer excretion times of drug clearance. This can be explained by the fact that the larger the dosage, the longer it takes for the drug to be absorbed and eventually metabolized. This process eventually lengthens the rate at which the drug is excreted from the system, as compared to an individual taking the drug at a lower dosage.

Chronic users of prednisone also take longer to excrete the drug because the metabolites are actively circulating in the system for a much longer time than in acute users of the drug. Therefore, a chronic user can take over a week to clear prednisone from the system while an acute user can take 11 to 16 hours to completely eliminate the drug.

Detoxification of Prednisone

Prednisone has an excretion half- life of an hour before it is converted to its active form, prednisolone. The peak half- life occurs 2 to 4 hours when prednisone is converted to prednisolone, with peak plasma concentration being attained within 1 to 2 hours. This implies that a high concentration of the drug is detectable in the blood plasma within 1 to 2 hours.

Therefore, a drug test taken within this timeframe will yield a definite positive result for prednisolone. After 2 hours, the concentration of the drug in the bloodstream begins to drop steadily but can be detected via the urine. Peak plasma concentrations of drugs are detectable via the blood while peak concentrations of metabolites are detected via the urine and other excretory organs such as sweat glands and hair follicles.

There are several ways to hasten the clearance of prednisone. These include discontinuation of use, frequent hydration, acidification of the urinary pH and use of CYP3A4 inducers. The discontinuation of prednisone must be done under the supervision of a medical practitioner.

The safest method of discontinuation of all corticosteroids is by tapering, meaning that the dose of the drug is tapered over a period of days, rather than sudden discontinuation. The acidification of the urinary pH can be achieved by increasing dietary intake of acidic foods such as lemon juice. The acid from the diet will acidify the urine and enhance clearance of prednisone.

Conversely, a diet rich in alkaline foods will slow down the excretion rate of the drug. CY3A4 is an enzyme that helps in the metabolism of prednisone. Therefore, ingestion of a drug that induces the action of this enzyme, such as ketoconazole, will also enhance the metabolism of prednisone, thereby, increasing the clearance rate.

CYP3A4 inhibitors such as Nifedipine prolong the clearance of prednisone because they temporarily interfere with the catalytic function of the enzyme that is responsible for catalyzing the reaction which breaks down prednisone into its active form of prednisolone, thereby, increasing the excretion timeframe. Foods such as grapefruit and pomegranate should be avoided if you would like prednisolone to clear at a faster rate.

It would be beneficial to take foods that induce the action of the enzyme CYP3A4. Frequent hydration with water will enhance the kidney’s ability to excrete the drug from the system. This means that the more water you take, the faster the prednisone will be cleared from the body.


Prednisone is a corticosteroid drug used for various conditions such as asthma and allergic dermatitis. Its metabolism results in the activation of its active component prednisolone. The prednisolone produces the corticosteroid effects on the body such as immunosuppression and anti- inflammatory. The drug is excreted effectively via the urine.

The clearance of prednisolone depends on individual factors such as dosage, acidity of the urine, age and body mass. Prednisone has a half- life of 2 to 4 hours, meaning that 50% of the drug is eliminated from the system within that time frame.

The total excretion of prednisone can last 6 to 22 hours. However, variations in several factors that influence its excretion can either prolong or shorten the total elimination time. In extreme cases, its clearance can even take up to 36 hours.


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