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What is the Difference Between Prednisone and Prednisolone?

What is the Difference Between Prednisone and Prednisolone?

Prednisolone is a precursor and an active form of prednisone. Moreover, the former has higher bioavailability than the latter. The following HealthHearty article gives a prednisone vs. prednisolone comparison in detail.
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Did You Know?
Prednisone is the most commonly prescribed synthetic corticosteroid for arthritis, and 5 mg of prednisone is equivalent to the body's daily output of cortisol―a hormone that allows the body to cope with stressful situations, such as trauma, surgery, infection, or emotional problems.

Both prednisone and prednisolone are classified as corticosteroids―drugs that help reduce inflammatory response of the immune system. These medications act as excellent anti-inflammatory agents that suppress the immune system, which works to reduce the inflammatory response associated with a wide range of auto-immune disorders such as asthma, ulcerative colitis, rheumatoid arthritis, and inflammatory skin problems. Veterinarians also prescribe these drugs to treat inflammatory conditions in dogs and cats.
Since both drugs are used for the same purpose, i.e., to treat anti-inflammatory conditions, even the side effects are more or less the same, which may lead us to believe that there is no difference between prednisone and prednisolone. However, this is not the case as one can find notable differences between these two drugs. These are discussed below:
Prednisone Vs.Prednisolone
Prednisone  Prednisolone
Type of Drug ♦ Prednisone is classified as a prodrug, meaning when the drug is taken, it is in an inactive state and gets metabolized in the liver to its active form. ♦ Prednisolone is the active form of prednisone. This conversion actually helps to enhance the bioavailability of the drug.
Structure ♦ Prednisone, in its inactive form, has a ketone group at the C11 position. ♦ When prednisone gets converted to prednisolone, the ketone group is replaced with hydroxyl group. In other words, the hydrogenation of the ketone group occurs at position 11, when prednisone is metabolized.
Considerations ♦ Since prednisone is metabolized in the liver, people with liver problems are usually not prescribed or administered prednisone. This is because when the liver does not function properly, its ability to convert prednisone to prednisolone reduces. ♦ Since prednisolone is already in its active form, it can be prescribed to people with liver conditions.
Bioavailability ♦ The bioavailability of prednisone is 80% to that of prednisolone. ♦ Prednisolone has higher bioavailability than its counterpart, hence it is easier to absorb.
♦ Half-life is the time taken to remove the drug to half its dose, from blood plasma. Prednisone, before it gets converted, has a half-life of about 1 hour.
♦ The half-life of prednisolone varies from 2 to 4 hours.
Conversion ♦ As prednisone is the precursor compound, it gets converted to prednisolone through metabolic process. ♦ The prednisolone formed is again metabolized, mainly in the liver, by the CYP3A4 enzyme to inactive compounds such as sulfate and glucuronide conjugates, which are eventually eliminated through urine.
Possible Side Effects
The possible side effects experienced are no different for prednisone and prednisolone. So, whether you are administered with the active or inactive form of the drug, some common side effects that may occur are given below:
  • Increased thirst and urination
  • Lethargy
  • Diarrhea
  • Vomiting
  • Trouble in sleeping
  • Headache
  • Increased appetite
  • Digestion problems

As both drugs suppress the immune system, they can make the patient susceptible to a wide range of infections. Moreover, existing infections may exacerbate and prolong the recovery time. Also, taking these medication for an extended duration of time can increase the risk of getting diabetes, Cushion's disease, and ulceration in the stomach.
On the whole, in most cases, patients with liver problems will be put on prednisolone to increase the potency of the treatment. Also, before recommending either medicine, the doctor evaluates the patient's condition and then decides whether the prescription would benefit the patient.
Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.