Glucocorticoids (corticosteroids, steroids).

Dexamethasone

Dexamethasone 2mg/5ml (as dexamethasone sodium phosphate)

Oral Solution A colourless to faint yellow solution with odour of mint

Dexamethasone is a corticosteroid. It is designed for use in certain endocrine and non-endocrine disorders, in certain cases of cerebral oedema and for diagnostic testing of adrenocortical hyperfunction.

Endocrine disorders:

Endocrine exophthalmos.

Non-endocrine disorders:

Dexamethasone may be used in the treatment of non-endocrine corticosteroid responsive conditions including:

Allergy and anaphylaxis: Anaphylaxis.

Arteritis collagenosis: Polymyalgia rheumatica, polyarteritis nodosa.

Haematological disorders: Haemolytic anaemia (also auto immune), leukaemia, myeloma, idiopathic thrombocytopenic purpura in adults,reticulolymphoproliferative disorders (see also under oncological disorders).

Gastroenterological disorders: For treatment during the critical stage in: ulcerative colitis (rectal only); regional enteritis (Crohn's disease), certain forms of hepatitis.

Muscular disorders: Polymyositis.

Neurological disorders: Raised intra-cranial pressure secondary to cerebral tumours, acute exacerbations of multiple sclerosis.

Ocular disorders: Anterior and posterior uveitis, optic neuritis, chorioretinitis, iridocyclitis, temporal arteritis, orbital pseudotumour.

Renal disorders: Nephrotic syndrome

Pulmonary disorders: Chronic bronchial asthma, aspiration pneumonitis, chronic obstructive pulmonary disease (COPD), sarcoidosis, allergic pulmonary disease such as farmer's and pigeon breeder's lung, Löffler's syndrome, cryptogenic fibrosing alveolitis.

Rheumatic disorders: some cases or specific forms (Felty's syndrome, Sjörgen's syndrome) of rheumatoid arthritis, including juvenile rheumatoid arthritis, acute rheumatism, lupus erythematosus disseminatus, temporal arteritis (polymyalgia rheumatica).

Skin disorders: Pemphigus vulgaris, bullous pemphigoid, erythrodermas, serious forms of erythema multiforme (Stevens-Johnson syndrome), mycosis fungoides, bullous dermatitis herpetiformis.

Oncological Disorders: lymphatic leukaemia, especially acute forms, malignant lymphoma (Hodgkin's disease, non-Hodgkin's lymphoma), metastasized breast cancer, hypercalcaemia as a result of bone metastasis or Kahler's disease, Kahler's disease.

Various: intense allergic reactions; as immunosuppressant in organ transplantation; as an adjuvant in the prevention of nausea and vomiting and in the treatment of cancer with oncolytics that have a serious emetic effec

General considerations:

The dosage should be titrated to the individual response and the nature of the disease. In order to minimise side effects, the lowest effective possible dosage should be used.

The initial dosage varies from 0.5 – 9mg a day depending on the disease being treated. In more severe diseases, doses higher than 9mg may be required. The initial dosage should be maintained or adjusted until the patient's response is satisfactory. Both the dose in the evening, which is useful in alleviating morning stiffness, and the divided dosage regimen are associated with greater suppression of the hypothalamo-pituitary-adrenal axis. If satisfactory clinical response does not occur after a reasonable period of time, discontinue treatment with dexamethasone and transfer the patient to another therapy.

If the initial response is favourable, the maintenance dosage should be determined by lowering the dose gradually to the lowest dose required to maintain an adequate clinical response. Chronic dosage should preferably not exceed 1.5mg dexamethasone daily.

Patients should be monitored for signs that may require dosage adjustment. These may be changes in clinical status resulting from remissions or exacerbations of the disease, individual drug responsiveness and the effect of stress (e.g. surgery, infection, trauma). During stress it may be necessary to increase dosage temporarily.

If the drug is to be stopped after more than a few days of treatment, it should be withdrawn gradually.

The following equivalents facilitate changing to dexamethasone from other glucocorticoids:

Milligram for milligram, dexamethasone is approximately equivalent to betamethasone, 4 to 6 times more potent than methylprednisolone and triamcinolone, 6 to 8 times more potent than prednisone and prednisolone, 25 to 30 times more potent than hydrocortisone, and about 35 times more potent than cortisone.

Acute, self-limiting allergic disorders or acute exacerbations of chronic allergic disorders.

The following dosage schedule combining parenteral and oral therapy is suggested:

First day: Dexamethasone sodium phosphate injection 4mg or 8mg (1ml or 2ml) intramuscularly.
 
Second day: 1mg (2.5ml) Dexamethasone Oral Solution twice a day.
 
Third day: 1mg (2.5ml) Dexamethasone Oral Solution twice a day.
 
Fourth day: 500micrograms (1.25ml) Dexamethasone Oral Solution twice a day.
 
Fifth day: 500micrograms (1.25ml) Dexamethasone Oral Solution twice a day.
 
Sixth day: 500micrograms (1.25ml) Dexamethasone Oral Solution.
 
Seventh day: 500micrograms (1.25ml) Dexamethasone Oral Solution.
 
Eighth day: Re-assessment.
 
If a dose of less than 5ml is required, an oral dosing device should be employed.

This schedule is designed to ensure adequate therapy during acute episodes whilst minimising the risk of overdosage in chronic cases.

Raised intracranial pressure: Initial therapy is usually by injection. When maintenance therapy is required, this should be changed to dexamethasone oral solution as soon as possible. For the palliative management of patients with recurrent or inoperable brain tumours, maintenance dosage should be calculated individually. A dosage of 2mg two or three times a day may be effective. The smallest dosage necessary to control symptoms should always be used.

Dexamethasone suppression tests:

1. Tests for Cushing's syndrome:

2mg (5ml) Dexamethasone Oral Solution should be administered at 11pm. Blood samples are then taken at 8am the next morning for plasma cortisol determination.

If greater accuracy is required, 500 micrograms (1.25ml) Dexamethasone Oral Solution should be administered every 6 hours for 48 hours. Blood should be drawn at 8am for plasma cortisol determination on the third morning.

24-hour urine collection should be employed for 17-hydroxycorticosteroid excretion determination.

2. Test to distinguish Cushing's syndrome caused by pituitary ACTH excess from the syndrome induced by other causes:

2mg (5ml) Dexamethasone Oral Solution should be administered every 6 hours for 48 hours. Blood should be drawn at 8am for plasma cortisol determination on the third morning.

24-hour urine collection should be employed for 17-hydroxycorticosteroid excretion determination.

Dosage should be limited to a single dose on alternate days to lessen retardation of growth and minimize suppression of hypothalamo-pituitary-adrenal axis.

Treatment of elderly patients, particularly if long term, should be planned bearing in mind the more serious consequences of the common side effects of corticosteroids in old age.

- Hypersensitivity to dexamethasone or any of the excipients listed.

- Systemic infection unless specific anti-infective therapy is employed.

- Systemic fungal infections.

- Stomach ulcer or duodenal ulcer

- Infection with tropical worms

Patients should carry 'steroid treatment' cards, which give clear guidance on the precautions to be taken to minimise risk, and which provides details of prescriber, drug, dosage and the duration of treatment.

Undesirable effects may be minimised by using the lowest effective dose for the minimum period. Dexamethasone Oral Solution may be given in divided doses as appropriate. Frequent patient review is required to appropriately titrate the dose against disease activity. When reduction in dosage is possible, the reduction should be gradual (Refer to 'Posology and Administration).

Anti-inflammatory/Immunosuppressive effects/Infection

Corticosteroids may exacerbate systemic fungal infections and should not be used unless they are needed to control drug reactions due to amphotericin. There have also been reports in which concomitant use of amphotericin and hydrocortisone was followed by cardiac enlargement and heart failure.

Administration of live virus vaccines is contra-indicated in individuals receiving immunosuppressive doses of corticosteroids. If inactivated viral or bacterial vaccines are administered to individuals receiving immunosuppressive doses of corticosteroids, the expected serum antibody response may not be obtained.

Suppression of the inflammatory response and immune function increases the susceptibility to infections and their severity. The clinical presentation may be atypical, and serious infections such as septicaemia and tuberculosis may be masked and may reach an advanced stage before being recognised.

Appropriate anti-microbial therapy should accompany glucocorticoid therapy when necessary e.g. in tuberculosis and viral and fungal infections of the eye.

There may be decreased resistance and inability to localise infection in patients on corticosteroids.

Chickenpox is of particular concern, since this normally minor illness may be fatal in immunosuppressed patients. Patients (or parents of children) without a definite history of chickenpox should be advised to avoid close personal contact with chickenpox or herpes zoster, and if exposed they should seek urgent medical attention. Passive immunisation with varicella/zoster immunoglobulin (VZIG) is needed by exposed non-immune patients who are receiving systemic corticosteroids or who have used them within the previous three months; this should be given within ten days of exposure to chickenpox. If a diagnosis of chickenpox is confirmed, the illness warrants specialist care and urgent treatment. Corticosteroids should not be stopped and the dose may need to be increased.

Measles can have a more serious or even fatal course in immunosuppressed patients. In such children or adults particular care should be taken to avoid exposure to measles. If exposed, prophylaxis with intramuscular pooled immunoglobulin (IG) may be indicated. Exposed patients should be advised to seek medical advice without delay.

Corticosteroids may activate latent amoebiasis or strongyloidiasis or exacerbate active disease. Latent disease may be activated or there may be an exacerbation of intercurrent infections due to pathogens, including those caused by Amoeba, Candida, Cryptococcus, Mycobacterium, Nocardia, Pneumocystis or Toxoplasma. It is recommended that these are ruled out before initiating corticosteroid therapy particularly in those patients who have spent time in the tropics or those with unexplained diarrhoea.

Prolonged use of corticosteroids may produce subcapsular cataracts, glaucoma with possible damage to the optic nerves, and may enhance the establishment of secondary ocular infections due to fungi or viruses.

General

A report shows that the use of corticosteroids in cerebral malaria is associated with a prolonged coma and an increased incidence of pneumonia and gastro-intestinal bleeding and therefore corticosteroids should not be used in cerebral malaria.

Average and large doses of hydrocortisone or cortisone can cause elevation of blood pressure, retention of salt and water, and increased excretion of potassium, but these effects are less likely to occur with synthetic derivatives, except when used in large doses. Dietary salt restriction and potassium supplementation may be necessary with corticosteroid therapy. All corticosteroids increase calcium excretion.

Adrenal Suppression:

Adrenal cortical atrophy develops during prolonged therapy and may persist for years after stopping treatment. Withdrawal of corticosteroids after prolonged therapy must therefore always be gradual to avoid acute adrenal insufficiency, being tapered off over weeks or months according to the dose and duration of treatment.

During prolonged therapy, any intercurrent illness, trauma , stressor surgical procedure will require a temporary increase in dosage; if corticosteroids have been stopped following prolonged therapy they may need to be temporarily re-introduced.

Patients under stress may require increased doses of corticosteroids prior, during and after the period of stressful situation.

Stopping corticosteroids after prolonged therapy may cause withdrawal symptoms including fever, myalgia, arthralgia and malaise. This may occur in patients even without evidence of adrenal insufficiency.

There is an enhanced effect of corticosteroids in patients with hypothyroidism and in those with cirrhosis.

Particular care is required when considering the use of systemic corticosteroids in patients with the following conditions and frequent patient monitoring is necessary:

- renal insufficiency

- hypertension or congestive heart failure

- diabetes mellitus (or a family history of diabetes)

- osteoporosis (especially post-menopausal females)

- previous corticosteroid-induced myopathy

- glaucoma (or family history of glaucoma)

- myasthenia gravis

- non-specific ulcerative colitis, diverticulitis or fresh intestinal anastomosis

- peptic ulceration

- existing or previous history of severe affective disorders (especially previous steroid psychosis)

- liver failure

- epilepsy

- migraine

- history of allergy to corticosteroids

- ocular herpes simplex, because of possible corneal perforation

- tuberculosis

- herpes simplex

- psychiatric disorders

Fat embolism has been reported as a possible complication of hypercortisonism.

Large doses of corticosteroids may mask the symptoms of gastro-intestinal perforation.

Reports in the literature suggest an apparent association between use of corticosteroids and left-ventricular free-wall rupture after a recent myocardial infarction; therefore, corticosteroids should be used with great caution in these patients.

Rare cases of anaphylactoid or hypersensitivity reactions have been reported especially with parenteral administration of corticosteroids. Prophylactic measures should be taken especially if the patient has a history of allergic reactions to medicines.

In rare cases, decrease or withdrawal of orally administered corticosteroids could reveal underlying disease that are accompanied by eosinophilia (e.g. Churg Strauss Syndrome) in patients with asthma.

Patients and/or carers should be warned that potentially severe psychiatric adverse reactions may occur with systemic steroids. Symptoms typically emerge within a few days or weeks of starting the treatment. Risks may be higher with high doses/systemic exposure, although dose levels do not allow prediction of the onset, type, severity or duration of reactions. Most reactions recover after either dose reduction or withdrawal, although specific treatment may be necessary. Patients/carers should be encouraged to seek medical advice if worrying psychological symptoms develop, especially if depressed mood or suicidal ideation is suspected. Patients/carers should also be alert to possible psychiatric disturbances that may occur either during or immediately after dose tapering/withdrawal of systemic steroids, although such reactions have been reported infrequently.

Particular care is required when considering the use of systemic corticosteroids in patients with existing or previous history of severe affective disorders in themselves or in their first degree relatives. These would include depressive or manic-depressive illness and previous steroid psychosis.

Use in Children

Corticosteroids cause growth retardation. Treatment should be limited to the minimum dose for the shortest period.

Children on prolonged therapy should be carefully monitored.

Excipient Warnings

The medicine contains benzoic acid which is a mild irritant to the skin, eyes and mucous membrane. It may also increase the risk of jaundice in newborn babies.

It also contains 0.7g sorbitol in each 5ml. When given according to the recommended dosage instructions, each dose will provide up to 3.1g of sorbitol. It is unsuitable in hereditary fructose intolerance and can cause stomach upset and diarrhoea.

It also contains liquid maltitol which may cause diarrhoea.

Effects of other medicinal products on dexamethasone:

Dexamethasone is metabolized via cytochrome P450 3A4 (CYP3A4). Concomitant administration of dexamethasone with inducers of CYP3A4, such as phenytoin, barbiturates, ephedrine, rifabutin, carbamazepine and rifampicin may lead to decreased plasma concentrations of dexamethasone and the dose may need to be increased. Concomitant administration of inhibitors of CYP3A4 such as ketoconazole, ritonavir and erythromycin may lead to increased plasma concentrations of dexamethasone.

These interactions may also interfere with dexamethasone suppression tests, which therefore should be interpreted with caution during administration of substances that affect the metabolism of dexamethasone.

Ketoconazole may increase plasma concentrations of dexamethasone by inhibition of CYP3A4, but may also suppress corticosteroid synthesis in the adrenal and thereby cause adrenal insufficiency at withdrawal of corticosteroid treatment.

Ephedrine may increase the metabolic clearance of corticosteroids, resulting in decreased plasma levels. An increase of the corticosteroid dose might be necessary.

False-negative results in the dexamethasone suppression test inpatients being treated with indometacin have been reported.

Antibiotics: Macrolide antibiotics have been reported to cause a significant decrease in corticosteroid clearance

Anticholinesterases: Concomitant use of anticholinesterase agents and corticosteroids may produce severe weakness in patients with myasthenia gravis. If possible, anticholinesterase agents should be withdrawn at least 24 hours before initiating corticosteroid therapy.

Colestyramine: Colestyramine may decrease the absorption of dexamethasone.

Estrogens, including oral contraceptives: Estrogens may decrease the hepatic metabolism of certain corticosteroids, thereby increasing their effect

Aminoglutethimide: Decrease of dexamethasone efficacy, due to its metabolism increase. An adjustment of dexamethasone dosage may be required.

Gastrointestinal topicals, antacids, charcoal: A decrease in digestive absorption of glucocorticoids have been reported with prednisolone and dexamethasone. Therefore, glucocorticoids should be taken separately from gastrointestinal topicals, antacids or charcoal, with an interval between treatment of at least two hours.

Effects of dexamethasone on other medicinal products

Dexamethasone is a moderate inducer of CYP3A4. Concomitant administration of dexamethasone with substances that are metabolised via CYP3A4 could lead to increased clearance and decreased plasma concentrations of these substances.

The renal clearance of salicylates is increased by corticosteroids and therefore, salicylate dosage should be reduced along with steroidal withdrawal.

The desired effects of hypoglycaemic agents (including insulin), anti-hypertensives and diuretics are antagonised by corticosteroids.

The hypokalaemic effects of acetazolamide, loop diuretics, thiazide diuretics, amphotericin B injection, potassium depleting agents, corticosteroids (gluco-mineralo), tetracosactide and carbenoxolone are enhanced. Hypokalaemia predisposes to cardiac arrhythmia especially “torsade de pointes” and increase the toxicity of cardiac glycosides. Hypokalemia should be corrected before corticosteroid treatment initiation. In addition, there have been cases reported in which concomitant use of amphotericin B and hydrocortisone was followed by cardiac enlargement and congestive heart failure.

Sultopride has been linked to ventricular arrhythmias, especially torsade de pointes. This combination is not recommended.

Patients taking NSAID's should be monitored since the incidence and/or severity of gastro-ulceration may increase. Aspirin should also be used cautiously in conjunction with corticosteroids in hypoprothrombinaemia.

Antitubercular drugs: Serum concentrations of isoniazid may be decreased.

Ciclosporin: Increased activity of both ciclosporin and corticosteroids may occur when the two are used concurrently. Convulsions have been reported with this concurrent use.

Thalidomide: Co-administration with thalidomide should be employed cautiously, as toxic epidermal necrolysis has been reported with concomitant use.

Corticosteroids may affect the nitrobuletetrazolium test for bacterial infection and produce false-negative results.

Vaccines attenuated live

Risk of fatal systemic disease

Praziquantel:

Decrease in praziquantel plasmatic concentrations, with a risk of treatment failure, due to its hepatic metabolism increased by dexamethasone.

Oral anticoagulants:

Possible impact of corticosteroid therapy on the metabolism of oral anticoagulants and on clotting factors. At high doses or with treatment for more than 10 days, there is a risk of bleeding specific to corticosteroid therapy (gastrointestinal mucosa, vascular fragility). Patients taking corticosteroids associated with oral anticoagulants should be closely monitored (biological investigations on 8^th day, then every 2 weeks during treatment and after treatment discontinuation)

Insulin, sulfonylureas, metformin:

Increase in blood glucose, with sometimes diabetic ketosis, since corticosteroids impair carbohydrate tolerance. Therefore, blood and urine self-monitoring should be reinforced by the patient, in particular at the start of treatment

Isoniazid:

A decrease in plasma isoniazid levels have been reported with prednisolone. The suggested mechanism is an increase in hepatic metabolism of isoniazid and a decrease in the hepatic metabolism of isoniazid and a decrease in the hepatic metabolism of glucocorticoids. Patients taking isoniazid should be closely monitored.

The incidence of predictable undesirable effects, including hypothalamic-pituitary-adrenal suppression correlates with the relative potency of the drug, dosage, timing of administration and the duration of treatment.

Reports in the literature suggest an apparent association between use of corticosteroids and left ventricular free wall rupture after a recent myocardial infarction; therefore corticosteroids should be used with great caution in these patients.

Fluid and electrolyte disturbances

Sodium retention, fluid retention, congestive heart failure in susceptible patients, potassium loss, hypokalaemic alkalosis, hypertension, increased calcium excretion.

Musculoskeletal

Osteoporosis, vertebral and long bone fractures, avascular necrosis, tendon rupture. Proximal myopathy. Muscle weakness, aseptic necrosis of femoral and humeral heads, loss of muscle mass.

Gastro-intestinal

Dyspepsia, peptic ulceration with perforation and haemorrhage, acute pancreatitis, candidiasis. Abdominal distension and vomiting. Ulcerative oesophagitis. Perforation of the small and large bowel particularly in patients with inflammatory bowel disease.

Dermatological

Impaired wound healing, thin fragile skin, petechiae and ecchymoses, erythema, striae, telangiectasia, acne, increased sweating, suppressed reaction to skin tests, other cutaneous reactions such as allergic dermatitis, urticaria, angioneurotic oedema, thinning scalp hair.

Ophthalmic

Posterior subcapsular cataracts, increased intra-ocular pressure, glaucoma, papilloedema, corneal or scleral thinning, exacerbation of ophthalmic viral or fungal diseases, exopthalmos.

Anti-inflammatory and immunosuppressive effects

Increased susceptibility and severity of infections with suppression of clinical symptoms and signs, opportunistic infections, recurrence of dormant tuberculosis. Decreased resistance to infection

Endocrine/metabolic

Menstrual irregularities and amenorrhoea, suppression of the hypothalamic-pituitary-adrenal axis, growth suppression in children and adolescents, premature epiphyseal closure, development of Cushingoid state, hirsutism, weight gain, impaired carbohydrate tolerance with increased requirement for anti-diabetic therapy. Negative protein and calcium balance. Secondary adrenocortical and pituitary unresponsiveness (particularly in times of stress, as in trauma, surgery or illness).

Neurological

Convulsions and aggravation of epilepsy, vertigo, headache, increased intra-cranial pressure with papilloedema in children (Pseudotumour cerebri), usually after treatment withdrawal, psychological dependence, depression, insomnia, aggravation of schizophrenia and psychic disturbances ranging from euphoria to frank psychotic manifestations.

A wide range of psychiatric reactions including affective disorders (such as irritable, euphoric, depressed and labile mood and suicidal thoughts), psychotic reactions (including mania, delusions, hallucinations and aggravation of schizophrenia), behavioural disturbances, irritability, anxiety, sleep disturbances and cognitive dysfunction including confusion and amnesia have been reported. Reactions are common and may occur in both adults and children. In adults, the frequency of severe reactions has been estimated to be 5-6%. Psychological effects have been reported on withdrawal of corticosteroids; the frequency is unknown.

General

Hypersensitivity including anaphylaxis has been reported. Leucocytosis, thromboembolism, increased appetite, nausea, malaise, hiccups, abnormal fat deposits, increased or decreased motility and number of spermatozoa.

Withdrawal symptoms and signs

Too rapid a reduction of corticosteroid dosage following prolonged treatment can lead to acute adrenal insufficiency, hypotension and death (See 'Special Warnings and Precautions').

A 'withdrawal syndrome' may also occur including fever, myalgia, arthralgia, rhinitis, conjunctivitis, painful itchy skin nodules and loss of weight.

Rosemont

(POM)