Prednisone

Introduction Overview

Generic Name

prednisone

Brand Name

Rayos, Sterapred, Deltasone

Dosage Form

tablet, delayed-release tablet, oral solution

Drug Class

Glucocorticoids (corticosteroids)

Pharmacokinetics

Absorption:
Prednisone is well absorbed from the gastrointestinal tract following oral administration. It undergoes rapid and extensive absorption with peak plasma concentrations occurring within 1 to 2 hours. The bioavailability of prednisone is high and consistent, allowing predictable systemic exposure. The absorption process can be influenced by food intake; however, prednisone is generally administered with food to minimize gastrointestinal irritation without affecting overall absorption. Its water solubility facilitates rapid uptake in the stomach and small intestine.

Distribution:
After absorption, prednisone is widely distributed throughout the body tissues and fluids. It has a moderate binding affinity to plasma proteins, primarily albumin and corticosteroid-binding globulin (transcortin), with approximately 90% of circulating drug bound. Prednisone exhibits good penetration into most body tissues including lungs, liver, and kidneys, but penetration into the cerebrospinal fluid is limited. The volume of distribution approximates total body water, reflecting both intracellular and extracellular distribution. Tissue distribution may be affected by inflammation and disease states, which can alter glucocorticoid receptor expression.

Metabolism:
Prednisone is a prodrug that requires hepatic conversion to its active form, prednisolone, via the enzyme 11-β-hydroxysteroid dehydrogenase type 1 predominantly in the liver. This biotransformation is critical for pharmacologic activity. Hepatic metabolism of prednisolone proceeds via reduction and conjugation pathways including hydroxylation by cytochrome P450 enzymes, primarily CYP3A4, followed by glucuronidation and sulfation. Factors such as liver impairment, enzyme induction or inhibition by concomitant drugs, and genetic polymorphisms can affect metabolism and thus the drug’s efficacy and toxicity.

Elimination:
Both prednisone and prednisolone have plasma elimination half-lives of approximately 3 to 4 hours. Prednisolone and its metabolites are primarily eliminated by renal excretion. Less than 10% of an oral dose is excreted unchanged in urine. The elimination processes are efficient, but renal dysfunction can potentially prolong the half-life. Prednisone’s pharmacokinetics allow once-daily or divided dosing schedules depending on clinical needs. Steady-state concentrations are typically achieved within a few doses. The drug’s elimination follows first-order kinetics, and the total clearance can be influenced by factors such as age, concomitant diseases, and polypharmacy.

Dosage Forms

Available Dosage Forms:
- Oral tablets: 1 mg, 2.5 mg, 5 mg, 10 mg, 20 mg, and 50 mg
- Delayed-release tablets (brand Rayos): designed for once-daily dosing with extended release
- Oral solution (liquid form) available for precise dosing, especially useful in pediatric and patients unable to swallow tablets

Dosages for Adults and Adolescents:
- Initial doses vary widely depending on the disease and severity, typically ranging from 5 mg to 60 mg daily
- Maintenance doses are adjusted individually, often the lowest effective dose to minimize adverse effects
- Dosing may be as a single morning dose or divided doses depending on clinical situation
- High dose therapy (above 40 mg daily) is used for acute inflammation or autoimmune flare-ups

Specific Patient Populations:
- Pediatric patients require weight-based dosing, with careful monitoring to avoid growth suppression
- Elderly patients may require dose adjustments due to altered metabolism and increased risk of adverse effects
- Patients with hepatic impairment may have altered metabolism requiring cautious dosing
- Use in pregnancy necessitates risk-benefit assessment; prednisone crosses the placenta and may cause low birth weight or fetal effects
- Breastfeeding considerations include potential drug transfer into breast milk and impact on the infant
- Tapering schedules are critical in long-term therapy to avoid adrenal insufficiency and withdrawal symptoms

Clinical Guidelines:
- Prednisone should always be administered with food to reduce gastrointestinal upset
- Delayed-release tablets are preferably taken in the evening to mimic the natural circadian rhythm of cortisol
- Dose adjustments should consider concurrent illnesses, infections, or surgical procedures as stress can increase corticosteroid requirements

Mechanism Of Action

Prednisone is a synthetic corticosteroid that exerts its effects primarily through binding to glucocorticoid receptors (GR) located in the cytoplasm of sensitive cells. Upon binding, the prednisone is converted to its active metabolite prednisolone, which then translocates into the nucleus where it acts as a ligand-activated transcription factor. This binding modulates the expression of multiple genes involved in inflammatory and immune responses.

At the molecular level, activated GR complexes bind glucocorticoid response elements (GREs) within DNA, enhancing or repressing transcription of anti-inflammatory proteins such as lipocortin-1, which inhibits phospholipase A2, thereby reducing the synthesis of pro-inflammatory eicosanoids (prostaglandins and leukotrienes). Concurrently, prednisone suppresses the expression of genes encoding cytokines like interleukins (IL-1, IL-6), tumor necrosis factor (TNF-alpha), and adhesion molecules, resulting in diminished recruitment and activation of inflammatory cells.

Beyond genomic effects, prednisone also affects cellular signaling pathways by inhibiting nuclear factor kappa B (NF-κB) and activator protein-1 (AP-1), which are critical transcription factors mediating inflammatory pathways. This leads to broad immunosuppressive effects, including reduced proliferation of T lymphocytes, decreased antibody production, and modulation of macrophage activity.

Clinically, these mechanisms translate into potent anti-inflammatory and immunosuppressive effects useful in treating autoimmune diseases, allergic reactions, and chronic inflammatory conditions. Compared to similar glucocorticoids, prednisone offers intermediate duration of action with a well-characterized safety profile. Ongoing research explores its role in modulating non-genomic signaling which might contribute to rapid effects observed shortly after administration.

Pharmacological Actions

Potent anti-inflammatory agent by inhibiting synthesis of inflammatory mediators
Suppresses immune response by modulating lymphocyte function and reducing antibody production
Inhibits phospholipase A2 activity, decreasing arachidonic acid derivatives
Reduces capillary permeability and edema associated with inflammation
Modulates gene transcription to upregulate anti-inflammatory proteins
Decreases adhesion molecule expression, limiting leukocyte migration to inflammation sites
Suppresses production and release of pro-inflammatory cytokines such as TNF-alpha, IL-1, IL-6
Exerts metabolic effects including gluconeogenesis and protein catabolism
Influences water and electrolyte balance by affecting renal function
Exerts anti-allergic effects by reducing histamine release and mast cell stabilization
Suppresses delayed hypersensitivity reactions and cell-mediated immunity
Modulates central nervous system effects contributing to mood and behavior changes

Therapeutic Or Clinical Uses

Management of allergic disorders including severe allergies and asthma
Treatment of autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis
Management of inflammatory bowel diseases including ulcerative colitis and Crohn’s disease
Control of dermatologic conditions such as psoriasis and severe dermatitis
Treatment of hematologic conditions like immune thrombocytopenic purpura
Suppression of immune rejection in organ transplantation
Management of chronic obstructive pulmonary disease (COPD) exacerbations
Treatment of adrenal insufficiency and congenital adrenal hyperplasia
Reduction of cerebral edema associated with brain tumors or trauma
Management of certain cancers as adjunct chemotherapy agent
Treatment of ophthalmic inflammatory diseases including uveitis
Use in acute lymphocytic leukemia as part of chemotherapy regimens
Management of severe anemias such as hemolytic anemia
Control of multiple sclerosis exacerbations
Treatment of nephrotic syndrome with inflammatory or autoimmune etiology

Side Or Adverse Effects

Insomnia and mood changes including depression and euphoria
Increased appetite leading to gradual weight gain
Acne and increased skin fragility with bruising
Delayed wound healing and thinning of the skin
Hyperglycemia and potential precipitation or worsening of diabetes mellitus
Osteoporosis with long-term use, increasing fracture risk
Glaucoma, cataracts, and other ocular complications
Muscle weakness and myopathy, especially with prolonged therapy
Increased susceptibility to infections due to immunosuppression
Gastrointestinal symptoms including nausea, stomach pain, and potential ulceration
Electrolyte imbalances such as hypokalemia
Cushingoid features including moon face and fat redistribution
Hypertension and fluid retention
Psychiatric disturbances including psychosis and personality changes
Adrenal insufficiency upon abrupt discontinuation of therapy

Precautions

Avoid use in patients with systemic fungal infections requiring oral antifungals
Caution in patients with active or latent tuberculosis
Monitor for signs of infection due to immunosuppressive effects
Use carefully in patients with diabetes mellitus, hypertension, or heart failure
Regular monitoring in patients with osteoporosis risk factors
Avoid abrupt discontinuation to prevent adrenal crisis; taper dosage gradually
Exercise caution in patients with psychiatric history due to risk of mood alterations
Monitor intraocular pressure in patients with glaucoma
Avoid live vaccines during and shortly after therapy
Adjust dosing in hepatic impairment due to altered metabolism
Consider potential drug interactions that may alter prednisone effectiveness
Caution in pregnancy and lactation; use only if benefits outweigh risks
Monitor growth in pediatric patients receiving long-term therapy
Use caution in patients with gastrointestinal ulcers or bleeding history
Assess electrolyte and fluid status periodically during therapy

Warnings

Prednisone can suppress the immune system increasing vulnerability to infections
Do not receive live vaccines while on therapy due to risk of vaccine-related infections
Abrupt withdrawal may cause adrenal insufficiency, leading to hypotension and shock
Long-term use is associated with significant risk of osteoporosis and fractures
May cause psychiatric adverse effects including severe depression, mania, or psychosis
High doses can cause Cushing's syndrome characterized by fat redistribution and metabolic derangements
Use with caution in patients exposed to chickenpox or measles due to risk of severe or fatal infection
Associated with increased risk of gastrointestinal perforation or bleeding especially with NSAIDs
Can cause increased blood glucose levels warranting monitoring in diabetic patients
May lead to delayed growth and development in pediatric patients
Prednisone should not be used in patients allergic to this drug or its components
Potential to cause eye disorders such as cataracts and glaucoma with prolonged use
Risk of pancreatitis has been reported during therapy
May exacerbate hypertension and heart failure due to fluid retention
Pregnancy use can result in low birth weight or harm to the fetus, especially in the first trimester

Contraindication

Hypersensitivity to prednisone or any corticosteroid ingredient
Systemic fungal infections requiring oral antifungal therapy
Patients with known systemic infections unless specific antimicrobial therapy is in place
Use caution or avoid in patients receiving live or attenuated vaccines
Caution or contraindication in patients with uncontrolled infections
Known systemic viral infections except in life-threatening situations under supervision
Do not use as sole therapy for bacterial or viral infections without appropriate antibacterial/antiviral agents
Avoid use in patients with peptic ulcer disease without medical supervision
Known glaucoma or cataracts without ophthalmic monitoring
Severe osteoporosis unless benefits outweigh risks
Patients with recent myocardial infarction or severe heart disease require caution
Untreated thyroid disorders until stabilized

Drug Interactions

Amphotericin B may increase risk of hypokalemia when used with prednisone
Cyclosporine plasma concentrations can be increased by corticosteroids leading to toxicity
Digoxin and other cardiac glycosides may have altered effects due to electrolyte imbalances
St. John's Wort may reduce effectiveness by inducing CYP3A4 metabolism of prednisone
Macrolide antibiotics such as clarithromycin can inhibit metabolism increasing corticosteroid levels
Azole antifungals (itraconazole, ketoconazole, etc.) inhibit prednisone metabolism leading to increased effects
Hormonal contraceptives may have altered metabolism when co-administered
Warfarin and other anticoagulants may have altered coagulation effects
Diuretics (loop and thiazide) may exacerbate electrolyte disturbances, especially hypokalemia
Hepatitis C antivirals boceprevir and telaprevir may interact affecting drug levels
HIV protease inhibitors and reverse transcriptase inhibitors can affect prednisone metabolism
Oral hypoglycemics or insulin dosage may need adjustment due to hyperglycemic effect
Non-steroidal anti-inflammatory drugs (NSAIDs) increase risk of gastrointestinal ulceration
Antiepileptics such as phenytoin, carbamazepine induce metabolism reducing prednisone efficacy
Antitubercular drugs (isoniazid, rifampin) induce metabolism reducing corticosteroid plasma levels

Preparations Of The Drug

Prednisone oral tablets in strengths: 1 mg, 2.5 mg, 5 mg, 10 mg, 20 mg, 50 mg
Delayed-release oral tablets (Rayos) formulated for extended release and once-daily dosing
Oral liquid formulations available for pediatric use or patients with difficulty swallowing
Prescriptions available for tapered dosing packs with decreasing prednisone doses
Combination products with other agents generally not used; prednisone usually dosed alone
Sterile injectable corticosteroids with different formulations (not prednisone but related agents)
Generic and brand name versions widely available with similar bioavailability
Formulations designed for administration with food to reduce gastrointestinal irritation
Packaged with medication guides outlining immunosuppression risk and tapering instructions
Storage at room temperature, protected from moisture and heat to maintain stability