Decadron (Dexamethasone)

Dexamethasone is a potent glucocorticoid medicine widely used for its anti-inflammatory and immunosuppressive effects. Dexamethasone was first synthesised in 1957. It is indicated for a range of conditions, including rheumatic disorders, severe allergies, asthma, skin diseases and certain types of cancer.

What is Dexamethasone?

Dexamethasone is a synthetic corticosteroid that mimics the effects of hormones produced by the adrenal glands. It works by reducing inflammation and suppressing the immune response. It is a white to almost white, odourless, crystalline powder that is stable in air and practically insoluble in water.

Indications

Control of severe or disabling allergic conditions that do not respond adequately to conventional treatment, including asthma, contact dermatitis, atopic dermatitis, perennial or seasonal allergic rhinitis, drug hypersensitivity reactions and serum sickness.

The medicine is used to treat dermatological diseases such as bullous dermatitis herpetiformis, mycosis fungoides, exfoliative erythroderma, pemphigus and severe erythema multiforme (Stevens-Johnson syndrome).

Dexamethasone is used to treat endocrine disorders such as primary or secondary adrenocortical insufficiency, hypercalcaemia associated with cancer, congenital adrenal hyperplasia and nonsuppurative thyroiditis.

It may also help with some gastrointestinal and eye conditions.

Dexamethasone may be indicated in haematologic disorders such as acquired (autoimmune) haemolytic anaemia, idiopathic thrombocytopenic purpura in adults, congenital (erythroid) hypoplastic anaemia (Diamond-Blackfan anaemia), pure red cell aplasia and selected cases of secondary thrombocytopenia.

In some cases, the medicine may be indicated for the palliative management of leukaemias and lymphomas.

Acute exacerbations of multiple sclerosis, craniotomy, and cerebral oedema associated with a primary or metastatic brain tumour, or head injury, can also be treated with Dexamethasone.

Dexamethasone may also be indicated to induce diuresis or remission of proteinuria in idiopathic nephrotic syndrome or when it is due to lupus erythematosus.

Respiratory diseases such as berylliosis, fulminating or disseminated pulmonary tuberculosis (when used together with appropriate antituberculous chemotherapy), idiopathic eosinophilic pneumonia and symptomatic sarcoidosis are among the indications for this medicine.

It may also help with some rheumatic disorders as adjunctive short-term therapy to help patients through an acute episode or exacerbation in acute gouty arthritis, ankylosing spondylitis, acute rheumatic carditis, rheumatoid arthritis, psoriatic arthritis and juvenile rheumatoid arthritis (selected cases may require low-dose maintenance therapy), as well as for the treatment of dermatomyositis, polymyositis and systemic lupus erythematosus.

Clinical Pharmacology

Glucocorticoids, whether synthetic or naturally occurring, are adrenocortical steroids that are readily absorbed from the gastrointestinal tract. Glucocorticoids have a range of metabolic effects. They also modify the body's immune responses to different stimuli.

It is approximately 25 times more potent than hydrocortisone (cortisol). It has minimal mineralocorticoid activity, which reduces the risk of fluid retention and other side effects associated with mineralocorticoid receptor activation. The medicine has a long half-life, which allows for once-daily dosing in many cases.

Ingredients

The active ingredient is Dexamethasone. Inactive ingredients may vary depending on the specific formulation and manufacturer.

It is available in various formulations, including oral tablets, oral solutions, injectable forms and topical applications.

What Are the Dosages of Dexamethasone?

The dosage of Dexamethasone varies depending on the condition being treated, how the patient responds, and the formulation used. Common dosages include:

• Oral tablets: 0.5 mg to 20 mg.
• Oral liquid: 0.5 mg/5 mL.
• Injectable solutions: varies depending on clinical need.

In Australia, your doctor will determine the dose that best suits the individual patient's needs.

Important Safety Information

Dexamethasone should be used with caution in patients with a history of infections, diabetes, high blood pressure or mental health disorders. Long-term use can lead to significant side effects, including osteoporosis, adrenal suppression and increased susceptibility to infections.

Rare cases of anaphylactoid reactions have occurred in patients receiving corticosteroid therapy.

Average and large doses of corticosteroids can cause raised blood pressure, sodium and water retention, and increased potassium excretion. These effects are less likely with synthetic derivatives, except when used in large doses. Dietary salt restriction and potassium supplements may be necessary.

If the patient is already receiving steroids, the dosage may need to be adjusted. Metabolic clearance of corticosteroids is decreased in patients with hypothyroidism and increased in patients with hyperthyroidism. Changes in the patient's thyroid status may require a dosage adjustment.

Corticosteroid therapy should be used with great caution in patients after a recent myocardial infarction.

Patients taking corticosteroids are more susceptible to infections than healthy individuals. These infections may range from mild to severe. Infection with any pathogen (viral, bacterial, fungal, protozoan or helminthic) in any part of the body may be associated with the use of corticosteroids alone or in combination with other immunosuppressive agents. As corticosteroid doses increase, the rate of infectious complications also rises. Be aware that corticosteroids can also mask some signs of an existing infection.

Corticosteroids may worsen systemic fungal infections and therefore should not be used when these infections are present unless they are needed to control life-threatening drug reactions. Cases have been reported in which the concomitant use of amphotericin B and hydrocortisone was followed by cardiac disease.

Latent disease may be activated, or intercurrent infections may worsen due to pathogens including those caused by Amoeba, Candida, Cryptococcus, Mycobacterium, Nocardia, Pneumocystis and Toxoplasma. It is recommended that latent amebiasis or active amebiasis be ruled out before starting corticosteroid therapy in any patient who has spent time in the tropics or has unexplained diarrhoea. Corticosteroids should also be used with great care in patients with known or suspected threadworm infestation. This medicine should not be used in cerebral malaria.

The use of corticosteroids in active tuberculosis should be restricted to cases of fulminating or disseminated tuberculosis in which the corticosteroid is used to manage the disease together with an appropriate antituberculous regimen. Close observation is necessary if corticosteroids are indicated in patients with latent tuberculosis or tuberculin reactivity.

Administration of live vaccines is contraindicated in patients receiving immunosuppressive doses of corticosteroids. Killed or inactivated vaccines may be given. However, the response to these vaccines cannot be predicted.

Chickenpox and measles can have a more severe or even fatal course in children and adults taking corticosteroids. In children and adults who have not had these diseases, particular care should be taken to avoid exposure.

Patients in Australia should be warned not to stop taking corticosteroids suddenly or without medical supervision. As prolonged use may cause adrenal insufficiency and make patients dependent on corticosteroids, they should tell any healthcare professional treating them that they are taking corticosteroids. They should seek medical advice straight away if they develop an acute illness, including fever or other signs of infection. Symptoms of corticosteroid withdrawal include myalgia, arthralgia and malaise. People taking corticosteroids should be warned to avoid exposure to chickenpox or measles.

Pregnancy and Breast-feeding

This medicine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Infants born to mothers who have received substantial doses of corticosteroids during pregnancy should be carefully observed for signs of hypoadrenalism.

Systemically administered corticosteroids appear in human milk and could suppress growth, interfere with endogenous corticosteroid production or cause other unwanted effects. A decision should be made whether to discontinue breast-feeding or stop the medicine, taking into account the importance of the medicine to the mother.

Pediatric Use

The efficacy and safety of corticosteroids in children are based on the well-established course of effect of corticosteroids, which is similar in children and adults. Published studies provide evidence of efficacy and safety in paediatric patients for the treatment of nephrotic syndrome in patients older than 2 years of age and aggressive lymphomas and leukaemias in patients older than 1 month of age. Other indications for paediatric use of corticosteroids, such as severe asthma and wheezing, are based on adequate and well-controlled trials conducted in adults on the premise that the course of the diseases and their pathophysiology are considered substantially similar in both populations. The side effects of corticosteroids in paediatric patients are similar to those in adults. To minimise the potential effects of corticosteroids on growth, paediatric patients should be titrated to the lowest effective dose.

Geriatric Use

Clinical studies did not include enough participants aged 65 and over to determine whether they respond differently from younger participants. In general, dose selection for an older patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of reduced hepatic, renal or cardiac function and concomitant disease or other medicine therapy. In particular, the increased risk of diabetes mellitus, fluid retention and hypertension in older patients treated with corticosteroids should be considered.

Prescription

In Australia, dexamethasone is available by prescription only. Contact your doctor to get a prescription.

Patients should follow their healthcare provider's instructions closely regarding dosage and treatment duration to help minimise the risks associated with corticosteroid therapy.

Contraindications to Dexamethasone

Dexamethasone should not be used in patients with:

• fungal infections;
• known hypersensitivity to Dexamethasone or any component of the formulation;
• certain viral infections (e.g. herpes simplex keratitis).

Side Effects

Side effects can include:

• Allergic reactions: anaphylaxis, anaphylactoid reaction, angioedema.
• Endocrine: development of a cushingoid state, decreased carbohydrate and glucose tolerance, glycosuria, hyperglycaemia, hypertrichosis, hirsutism, manifestations of latent diabetes mellitus, increased requirements for insulin or oral hypoglycaemic agents in diabetes, secondary adrenocortical and pituitary unresponsiveness (particularly in times of stress, as in trauma, surgery or illness), menstrual irregularities, suppression of growth in paediatric patients.
• Dermatologic: allergic dermatitis, acne, ecchymoses and petechiae, dry scaly skin, erythema, increased sweating, impaired wound healing, striae, rash, suppression of reactions to skin tests, thinning scalp hair, thin fragile skin, urticaria.
• Metabolic: negative nitrogen balance due to protein catabolism.
• Cardiovascular: cardiac arrest, bradycardia, cardiac arrhythmias, circulatory collapse, cardiac enlargement, fat embolism, congestive heart failure, hypertrophic cardiomyopathy in premature infants, hypertension, myocardial rupture following recent myocardial infarction, oedema, syncope, tachycardia, pulmonary oedema, thrombophlebitis, thromboembolism, vasculitis.
• Gastrointestinal: elevation in serum liver enzyme levels (usually reversible on discontinuation), abdominal distention, hepatomegaly, nausea, peptic ulcer with possible perforation and haemorrhage, pancreatitis, perforation of the small and large intestine (particularly in patients with inflammatory bowel disease), ulcerative oesophagitis.
• Fluid and electrolyte disturbances: fluid retention, congestive heart failure in susceptible patients, potassium loss, hypokalaemic alkalosis, sodium retention.
• Musculoskeletal: loss of muscle mass, aseptic necrosis of femoral and humeral heads, muscle weakness, pathological fracture of long bones, osteoporosis, steroid myopathy, vertebral compression fractures, tendon rupture.
• Ophthalmic: glaucoma, exophthalmos, posterior subcapsular cataracts, increased intraocular pressure.
• Neurological/Psychiatric: depression, convulsions, euphoria, headache, emotional instability, increased intracranial pressure with papilloedema (pseudotumour cerebri) usually following discontinuation of treatment, mood swings, insomnia, neuropathy, neuritis, paraesthesia, psychic disorders, personality changes, vertigo.
• Other: decreased resistance to infection, abnormal fat deposits, increased or decreased motility and number of spermatozoa, hiccups, moon face, malaise, weight gain.

Patients should report any severe or persistent side effects to their Australian healthcare provider.

Interactions of Dexamethasone with Other Medicines

Dexamethasone can interact with various medicines:

• Cholestyramine: it may increase the clearance of corticosteroids.
• Aminoglutethimide: it may reduce adrenal suppression caused by corticosteroids.
• Dexamethasone suppression test (DST): false-negative results in the dexamethasone suppression test (DST) have been reported in patients treated with indomethacin.
• Amphotericin B injection and potassium-depleting agents: patients should be observed closely for the development of hypokalaemia. Moreover, cases have been reported in which concomitant use of amphotericin B and hydrocortisone was followed by cardiac enlargement and congestive heart failure.
• Digitalis glycosides: patients taking digitalis glycosides may be at increased risk of arrhythmias due to hypokalaemia.
• Antibiotics: macrolide antibiotics have been reported to cause a significant decrease in corticosteroid clearance.
• Ephedrine: it may increase the metabolic clearance of corticosteroids, resulting in lower blood levels and reduced physiological activity, which may require an increased corticosteroid dose.
• Anticholinesterases: concomitant use of anticholinesterase agents and corticosteroids may produce severe weakness in patients with myasthenia gravis.
• Estrogens, including oral contraceptives: these medicines may decrease the hepatic metabolism of certain corticosteroids, thereby increasing their effect.
• Oral anticoagulants: co-administration of corticosteroids and warfarin usually results in inhibition of response to warfarin. However, some conflicting reports have been published.
• Hepatic Enzyme Inducers, Inhibitors, and Substrates: these medicines may increase corticosteroid metabolism and require the corticosteroid dose to be increased.
• Antidiabetics: because corticosteroids may increase blood glucose concentrations, dose adjustments of antidiabetic agents may be required.
• Ketoconazole: ketoconazole has been reported to decrease the metabolism of certain corticosteroids by up to 60%, leading to an increased risk of corticosteroid side effects. It can also inhibit adrenal corticosteroid synthesis and may cause adrenal insufficiency during corticosteroid withdrawal.
• Antitubercular drugs: serum concentrations of isoniazid may be decreased.
• Nonsteroidal anti-inflammatory agents (NSAIDs): concomitant use of aspirin (or other nonsteroidal anti-inflammatory agents) and corticosteroids increases the risk of gastrointestinal side effects.
• Cyclosporine: increased activity of both ciclosporin and corticosteroids may occur when the two are used together. Convulsions have been reported with this concurrent use.
• Vaccines: patients on corticosteroid therapy may have a reduced response to toxoids and live or inactivated vaccines because of an inhibited antibody response.
• Skin tests: corticosteroids may suppress reactions to skin tests.
• Phenytoin: post-marketing experience has included reports of both increases and decreases in phenytoin levels with dexamethasone co-administration, leading to changes in seizure control.
• Thalidomide: co-administration with thalidomide should be used cautiously, as toxic epidermal necrolysis has been reported with concomitant use.

Overdose of Dexamethasone

While an overdose of Dexamethasone is not usually life-threatening, it can lead to severe side effects such as hypertension, gastrointestinal bleeding or psychiatric symptoms. If overdose is suspected, seek immediate medical attention.

Storage

Dexamethasone should be stored at room temperature, away from moisture and heat. Keep it out of the reach of children and dispose of any unused medicine properly.

Benefits of Using Dexamethasone

Check additional information about this medicine here. The information is provided by Australia's Therapeutic Goods Administration (TGA).