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What is Dexamethasone?
Dexamethasone is a corticosteroid that is widely used for the treatment of several diseases and infections including Rheumatic disease, skin infections, hypersensitivity reactions, types of cancer, eye infections, ulcerative colitis, Chronic Obstructive Pulmonary Disorder (COPD), and also in combination therapy with antibiotics for Tuberculosis treatment.
- It is effects are based on its anti-inflammatory responses and suppression of the body’s immune responses.
- It as an oral tablet, that is available as a generic form and brand form. The generic name is dexamethasone and the brand name is DexPak.
- It also comes in other forms including, oral solutions, eye drops, and ear drops, and injectable solution or intraocular solution which is used after eye surgery.
- It is not to be consumed during breastfeeding, despite being proved to have n effect during pregnancy.
- Dexamethasone was first designed in 1957 and later approved for medical use in 1961. It is one of the drugs listed by the WHO in the list of Essential drugs.
Properties of Dexamethasone
- Dexamethasone is a synthetic adrenal corticosteroid with anti-inflammatory properties referred to as the anti-inflammatory 9-fluoro-glucocorticoid i.e it is a glucocorticoid agonist.
- Dexamethasone bind to specific nuclear steroid receptors to initiate the mechanism of action of anti-inflammation and immuno-suppression.
- Possessing the anti-inflammatory and immunosuppressive properties, it has the ability to penetrate the central nervous system (CNS), hence it can be used in the management of cerebral edema along with tobramycin.
- It also interferes with the activation of the Natural Killer cells and the apoptotic pathway.
- Also used to manage congenital adrenal hyperplasia, dexamethasone prevents masculinization (development of sex differences between a male and a female) of a female fetus.
- Other properties include:
- It is highly soluble, at an 80-90% rate
- It has a melting point of 262C (504F).
- It is highly binding to transcription proteins.
- It is metabolized in the liver and excreted in the urine.
- Its elimination rate is within a span of 2-3 hours.
Dexamethasone Mechanism of action
As an anti-inflammatory drug, dexamethasone bind to the DNA of glucocorticoid properties to modify transcription proteins inhibiting leukocyte infiltration to the site of inflammation, interfering with the effect of inflammatory mediators, suppress humoral responses and reduce edema and/or scarring of tissues.
- Anti-inflammatory Drug
- Dexamethasone is a corticosteroid, that is widely used in the treatment of inflammatory and autoimmune disorders including rheumatoid arthritis, thrombocytopenia, and bronchospasm.
- The blockage of the airway called croup which is common in children can be treated with a dose of dexamethasone.
- It has also been used in treating anaphylactic shock caused by allergies.
- Retinal occlusion, inflammation of the uvea (pigment between the retina and the cornea), and diabetic macular edema can be treated with the use of dexamethasone eye implants.
- Combination therapies of dexamethasone with antibiotics have been used to treat endophthalmitis.
- Intravenous administration of dexamethasone has been used to reduce inflammation of the myocardium by reducing cardiac pacing in individuals with artificial pacemakers to maintain their heartbeat.
- It is also used to reduce inflammation in individuals with diagnosed bacterial meningitis by minimizing the inflammatory responses of the body to the bacteria. This treatment is immediately followed up by the use of antibiotics.
- Cancer treatment and management
- Dexamethasone along with other drugs is approved for use in the management of various cancers including leukemia, lymphomas, mycosis fungoides (cutaneous T-cell lymphoma), and conditions that are related to cancer such as anemia, cerebral edema, allergies, hypercalcemia, and thrombocytopenia.
- Dexamethasone is commonly administered to individuals undergoing chemotherapy to reduce the side effects that arise due to chemo treatment such as cancer-related fatigue, pain, insomnia, nutritional deficit, anxiety, and depression.
- Dexamethasone has also been used to prevent cerebral edema in individuals with brain tumors
- It is also administered as a chemotherapeutic drug in persons with multiple myeloma in combination with other chemotherapeutic drugs.
- Treatment of endocrine disorders
- Rare conditions of the endocrine system where resistance to glucocorticoids is experienced, dexamethasone has been used such as Addison’s disease.
- Dexamethasone is also used to suppress adrenocorticotropic hormone (ACTH) production in adolescents and adults with congenital adrenal hyperplasia, conditions that involve excessive or suppressed production of sex steroids altering the development of sex characteristics.
- Management of Cerebral edema and pulmonary edema
- Dexamethasone is used to suppress accumulation of fluids in the brain (brain edema) in persons with brain tumors
- It also prevents fluid accumulation in the respiratory cavities (pulmonary edema) in persons with tuberculosis.
- It is administered along with other drugs, majorly antibiotics
- Prevention of nausea and vomiting
- Post-surgery patients can be given dexamethasone to prevent post-surgical pains and in individual administered with long-acting spinal or epidural spinal opioids.
- In combination with antagonists like ondansetron (a drug that prevents nausea and vomiting), dexamethasone is used to prevent postoperative nausea and vomiting.
- Treatment of Upper Respiratory disorders
- Dexamethasone has been used to relieve pain and discomfort caused by common colds and sore throats, and to also improve and speed up recovery from upper respiratory tract infections.
- During pregnancy, dexamethasone has been administered to prevent congenital adrenal hyperplasia and to promote fetal development.
Dexamethasone Interactions and Contraindications
Some elements that are being administered to individuals due to illnesses or preventive cautions can interact with dexamethasone such as:
- Aminoglutethimide is an adrenal steroid inhibitor
- Oral contraceptives
- Phenytoin, a drug used for the treatment of epilepsy
- Blood thinners (dabigatran)
- Nonsteroid Anti-inflammatory Drugs (NSAIDs) such as aspirin, ibuprofen,
- Cancer treatment drugs such as dasatinib, sunitinib, lapatinib, aldesleukin
- Cholestyramine used to lower cholesterol in the blood
- Digoxin used in the treatment of heart failure and improve heartbeat.
- Isoniazid for treatment of tuberculosis
- Mifepristone an abortion drug
- Rilpivirine used in HIV treatment
- Thalidomide used to treat Hansen’s disease of the skin and multiple myeloma
Dexamethasone should not be used in cases where individuals have certain infections. These are the contraindications of dexamethasone which include:
- Allergic responses to dexamethasone
- Cerebral malaria
- Systemic fungal infections such as aspergillosis, blastomycosis, cryptococcosis
- Treatment of smallpox vaccine, concurrently with dexamethasone
- Liver disease
- Thyroid disorders
- Muscle disorders
- Ocular herpes
- Ulcerative colitis
- Congestive heart failure
- Depression or mental disorders
- High blood pressure
Dexamethasone side effects
Side effects arising from dexamethasone administration are few and they may include:
- Stomach pain and crumping
- Change in the menstrual cycle
- Increased appetite
- Weight gain
- Drying and thinning of the skin
- Vision change
Dexamethasone and COVID-19
- COVID-19 which causes a cluster of respiratory symptoms associated with the inflammation and accumulation of fluids in the lungs has no approved treatment yet and several drug agents are on research to test for efficacy against the viral infection caused by SARS-CoV-2, a variant of coronavirus.
- Dexamethasone was one of the drugs selected for trial by the RECOVERY (randomized Evaluation of COVID-19 Therapy) trial at Oxford University, UK.
- Dexamethasone is a corticosteroid widely used to treat a range of infections and its mechanism of action is its ability to reduce inflammation and suppress immune reactions elicited during an infection.
- Dexamethasone reduced deaths by one-third in ventilated patients (rate ratio 0.65 [95% confidence interval 0.48 to 0.88]; p=0.0003) and by one fifth in other patients receiving oxygen only (0.80 [0.67 to 0.96]; p=0.0021). There was no benefit among those patients who did not require respiratory support (1.22 [0.86 to 1.75]; p=0.14). (Source)
- However, assumptions can be made based on the known effect of the drug and the pathology of COVID-19.
- COVID-19 causes rapid accumulation of cytokines majorly IL-6 in the lungs. IL-6 is responsible for increasing inflammation in the lung cavity which causes the production and accumulation of fluids in the lungs. And dexamethasone being a steroid whose mechanism is of reducing inflammation and suppressing immune activation of immune agents, the drug could be inducing the anti-inflammatory effects and reducing the secretion of cytokines into the lungs. This improves the outcome of patients with high morbidity i.e patients severely ill and on ventilation by relieving the symptoms of the lung effects.
- The drug is cheap and widely available and the WHO and the FDA have authorized the use of the drug in severely ill patients.
- Moreover, research is still underway in understanding the effect caused by dexamethasone and the pathology of lung hyperactive relive produced by the drug.
References and Sources