Prednisolone

Prednisolone is the active metabolite of prednisone,^[1] which is also used as a drug.

Uses

Prednisolone is a corticosteroid drug with predominant glucocorticoid and low mineralocorticoid activity, making it useful for the treatment of a wide range of inflammatory and auto-immune conditions^[2] such as asthma^[3], uveitis, pyoderma gangrenosum, rheumatoid arthritis, ulcerative colitis, temporal arteritis and Crohn's disease, Bell's palsy, multiple sclerosis,^[4] cluster headaches, vasculitis, acute lymphoblastic leukemia and autoimmune hepatitis,^[5] systemic lupus erythematosus, and dermatomyositis. It is also used for treatment of sarcoidosis, though the mechanism is unknown.

Prednisolone acetate ophthalmic suspension (eye drops) is an adrenocortical steroid product, prepared as a sterile ophthalmic suspension and used to reduce swelling, redness, itching, and allergic reactions affecting the eye.

Prednisolone can also be used as an immunosuppressive drug for organ transplants and in cases of adrenal insufficiency (Addison's).

Corticosteroids inhibit the inflammatory response to a variety of inciting agents and, it is presumed, delay or slow healing. They inhibit the edema, fibrin deposition, capillary dilation, leukocyte migration, capillary proliferation, fibroblast proliferation, deposition of collagen, and scar formation with inflammation.

Mechanism of action

Prednisolone irreversibly binds with glucocorticoid receptors (GR) alpha and beta for which they have a high affinity. AlphaGR and BetaGR are found in virtually all tissues with variable numbers between 3000 and 10000 per cell, depending on the tissue involved. Prednisolone can activate and influence biochemical behaviour of most cells. The steroid/receptor complexes dimerise and interact with cellular DNA in the nucleus, binding to steroid-response elements and modifying gene transcription. They both induce synthesis of some genes and, therefore, some proteins, and inhibit synthesis of others.^[6][7]

Not all metabolic actions on genes are known. Most mediator proteins are enzymes, e.g., cAMP-dependent kinase

Anti-inflammatory and immunosuppressive actions:

• Inhibition of gene transcription for COX-2, cytokines, cell adhesion molecules, and inducible NO synthetase
• Blockage of Vit D3-mediated induction of osteocalcin gene in osteoblasts
• Modification of collegenase gene transcription
• Increase synthesis annexin-1, important in negative feedback on hypothalamus and anterior pituitary gland
• Anti-inflammatory action, it is presumed.

Regulation of gene suppression leads to systemic suppression of inflammation and immune response. This is of clinical usefulness but ultimately leads to gluconeogenesis protolysis and lypolysis. Gene transcription returns to normal after cessation, but sudden stoppage can cause Addison's disease. Osteoporosis is permanent.

Adverse effects

Possible side-effects include fluid retention of the face (moon face, Cushing's syndrome), acne, constipation, and mood swings.

A lengthy course of prednisolone can cause bloody or black tarry stools from bleeding into the stomach (this requires urgent medical attention); filling or rounding out of the face; muscle cramps or pain; muscle weakness; nausea; pain in back, hips, ribs, arms, shoulders, or legs; reddish-purple stretch marks on arms, face, legs, trunk, or groin; thin and shiny skin; unusual bruising; urinating at night; rapid weight gain; and wounds that will not heal.

Prolonged use of prednisolone can lead to the development of osteoporosis which makes bones more fragile and susceptible to fractures. One way to help alleviate this side effect is through the use of calcium and vitamin D supplements.^[8]

Swelling of the pancreas has also been reported.

Prednisolone can cause increased blood sugar levels for diabetics.

Other effects include decreased or blurred vision, increased eye pressure, increased thirst, cataract formation, confusion, rare cases of dementia in otherwise-healthy elderly patients, and nervousness.

Loteprednol is an analog drug that has reduced adverse ocular effects.

Prednisolone may also cause insomnia.

Nasal septum perforation and bowel perforation are also notable adverse effects that restrict steroids' use in some pathologic conditions.^{[9] [10]}

Banned status in athletics

As a glucocorticosteroid, use of prednisolone during competition via oral, intravenous, intramuscular or rectal routes is banned under WADA anti-doping rules.^[11] Local or topical use of prednisolone during competition as well as any use out of competition is not regulated.

References