DEXMETHSONE

What it is

DEXMETHSONE contains dexamethasone, a synthetic adrenocorticosteroid with glucocorticoid activity that is approximately 25 to 30 times as potent as hydrocortisone. Unlike hydrocortisone, dexamethasone has little if any mineralocorticoid activity. DEXMETHSONE has anti-inflammatory and immunosuppressant activity. The brand is available as a tablet in two strengths.

Approved indications —

Acute adrenocortical insufficiency, including Addison's disease and bilateral adrenalectomy — Relative adrenocortical insufficiency — Systemic lupus erythematosus, polyarteritis nodosa, dermatomyositis, giant cell arteritis — Acute rheumatic carditis — Status asthmaticus, chronic asthma, sarcoidosis, respiratory insufficiency — Leukaemia, idiopathic thrombocytopaenic purpura in adults, acquired (autoimmune) haemolytic anaemia — Rheumatoid arthritis, osteoarthritis — Psoriasis, erythema multiforme, pemphigus, neutrophilic dermatitis, localised neurodermatitis, exfoliative dermatitis, severe seborrhoeic dermatitis, contact dermatitis — Ulcerative colitis, regional enteritis — Cerebral oedema associated with primary or metastatic brain tumours, neurosurgery or stroke — Allergic conjunctivitis, keratitis, allergic corneal marginal ulcers, chorioretinitis, optic neuritis, anterior ischaemic optic neuropathy — Cerebral neoplasms, hypercalcaemia associated with cancer, leukaemias and lymphomas in adults, acute leukaemia in children

Dosing overview

Dosage requirements are variable and must be individualised on the basis of the disease being treated and patient response.

Key safety warnings

Tumour lysis syndrome has been reported in patients with haematological malignancies following the use of dexamethasone alone or in combination with other chemotherapeutic agents. Patients at high risk of tumour lysis syndrome, such as those with high proliferative rate, high tumour burden and high sensitivity to cytotoxic agents, should be monitored closely and appropriate precaution taken. The excipient sodium sulfite may rarely cause severe hypersensitivity reactions and bronchospasm. The vial stopper contains dry natural rubber (a derivative of latex), which may cause severe allergic reactions. Long-term treatment should not be abruptly discontinued, as too rapid withdrawal may lead to drug induced secondary adrenocortical insufficiency. This may be minimised by gradual dosage reduction. Pharmacologic doses of corticosteroids administered for prolonged periods may result in hypothalamic-pituitary-adrenal suppression. The degree and duration of adrenocortical insufficiency produced is variable among patients and depends on the dose, frequency, time of administration and duration of therapy. Suppression of the inflammatory response and immune function increases susceptibility to or masks the symptoms of infections, and their severity. Immunosuppression is most likely to occur in patients receiving longer term, high dose systemic corticosteroid treatment; however, patients receiving moderate doses for short periods, or low doses over a prolonged period, may also be at risk. Patients and/or carers should be warned that potentially severe psychiatric reactions may occur. Symptoms typically emerge within a few days or weeks of starting treatment. Most reactions recover after either dose reduction or withdrawal, although specific treatment may be necessary.

Contraindications

DEXMETHSONE is contraindicated in systemic fungal infections, or other systemic infections unless specific anti-infective therapy is given; hypersensitivity to dexamethasone or other corticosteroids or to any component of the injection (including sulfites); administration of live virus vaccines; in patients with myasthenia gravis, peptic ulcer, osteoporosis or psychoses; and in local injection for patients with bacteraemia, unstable joints, or infection at the injection site.

PBS listing

DEXMETHSONE tablets 500 micrograms are listed on the PBS with unrestricted and restricted items at an ex-manufacturer price of A$2.50, and tablets 4 mg are listed with one unrestricted item at an ex-manufacturer price of A$4.84.

Regulatory history

DEXMETHSONE was first registered on the ARTG on 21 October 1991, with two tablet formulations listed: 500 micrograms and 4 mg, both in bottle presentations.