Dexamethasone Sodium Phosphate

ADMINISTRATION ROUTES:

IV, PO

ALTERNATIVE NAMES:

Dexamethasone

ICU INDICATIONS:

1. Cerebral oedema
2. Upper airway oedema
3. Nausea and vomiting
4. Croup
5. Other inflammatory conditions

PRESENTATION AND ADMINISTRATION:

IV:

4mg/1 mL vial and 8mg/2 mL vial

Inject undiluted over 3-5 minutes

Compatible with the following IV fluids:

0.9% Sodium chloride, Glucose and Sodium Chloride, 5% Dextrose

Store at room temperature. Protect from light and freezing

PO:

1mg and 4mg tablets (white)

DOSAGE:*

IV/PO:

Cerebral oedema:

8-16 mg stat, then 4-8mg 4 hrly Reduce over 3-5 days to 2 mg 8-12 hrly

Nausea:

4-8 mg IV stat

Adult airway oedema:

8-16 mg 1 hr pre-extubation May be repeated TDS if symptoms persist (but consider alternative causes)

DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:

Dose as in normal renal function

DOSAGE IN PAEDIATRICS:

IV / PO:

Cerebral oedema:

0.25 - 1 mg/kg stat then 0.1-0.2 mg/kg 4 hourly Reduce over 3 - 5 days to 0.05 mg/kg 8 - 12 hourly

Severe croup or extubation stridor:

0.6 mg/kg stat IV then 1 mg/kg prednisone 8 - 12 hourly

CLINICAL PHARMACOLOGY:

Dexamethasone is a glucocorticoid which is 25 times more potent than hydrocortisone with respect to its glucocorticoid activity; it has no mineralocorticoid effect. Naturally occurring glucocorticoids (hydrocortisone and cortisone), which also have salt-retaining properties, are used as replacement therapy in adrenocortical deficiency states. Their synthetic analogues, including dexamethasone, are primarily used for their potent anti- inflammatory effects in disorders of many organ systems.

CONTRAINDICATIONS:

1. Systemic fungal infections
2. Hypersensitivity to dexamethasone or any component of the product

WARNINGS:

Anaphylaxis:

Anaphylactoid and hypersensitivity reactions have been reported for dexamethasone sodium phosphate injection

Dexamethasone sodium phosphate injection contains sodium bisulfite, a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life-threatening, or less severe asthmatic episodes in certain susceptible people. The overall prevalence of sulfite sensitivity in the general population is unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than in nonasthmatic people

Exacerbation of fungal infections:

Corticosteroids may exacerbate systemic fungal infections and therefore should not be used in the presence of such infections unless they are needed to control drug reactions due to amphotericin B

Relative steroid deficiency:

In patients on corticosteroid therapy subjected to any unusual stress, increased dosage of rapidly acting corticosteroids before, during, and after the stressful situation is indicated. Drug-induced secondary adrenocortical insufficiency may result from too rapid withdrawal of corticosteroids and may be minimised by gradual reduction of dosage. This type of relative insufficiency may persist for months after discontinuation of therapy; therefore, in any situation of stress occurring during that period, hormone therapy should be reinstituted

Masking of signs of infection:

Corticosteroids may mask some signs of infection, and new infections may appear during their use.

PRECAUTIONS:

General:

Psychic derangements may appear when corticosteroids are used, ranging from euphoria, insomnia, mood swings, personality changes, and severe depression to frank psychotic manifestations. Also, existing emotional instability or psychotic tendencies may be aggravated by corticosteroids

Laboratory Tests:

No tests in addition to routine ICU tests are indicated

Drug/Laboratory Test Interactions:

None known

IMPORTANT DRUG INTERACTIONS IN ICU:

Phenytoin, phenobarbital, ephedrine, and rifampin may enhance the metabolic clearance of corticosteroids resulting in decreased blood levels and lessened physiologic activity, thus requiring adjustment in corticosteroid dosage

ADVERSE REACTIONS:

Fluid and electrolyte disturbances:

Sodium retention, fluid retention, congestive heart failure in susceptible patients, potassium loss, hypokalemic alkalosis, hypertension

Musculoskeletal:

Muscle weakness, steroid myopathy, loss of muscle mass, osteoporosis, vertebral compression fractures, aseptic necrosis of femoral and humeral heads, pathologic fracture of long bones, tendon rupture

Gastrointestinal:

Peptic ulcer with possible subsequent perforation and haemorrhage, perforation of the small and large bowel, particularly in patients with inflammatory bowel disease, pancreatitis, abdominal distention, ulcerative oesophagitis

Dermatologic:

Impaired wound healing, thin fragile skin, petechiae and ecchymoses, erythema, increased sweating, may suppress reactions to skin tests, burning or tingling, especially in the perineal area (after IV injection), other cutaneous reactions, such as allergic dermatitis, urticaria, angioneurotic oedema

Neurologic:

Convulsions, increased intracranial pressure with papilloedema (pseudotumour cerebri) usually after treatment, vertigo, headache, psychic disturbances

Endocrine:

Menstrual irregularities, development of Cushingoid state, suppression of growth in children, secondary adrenocortical and pituitary unresponsiveness, particularly in times of stress, as in trauma, surgery, or illness, decreased carbohydrate tolerance, manifestations of latent diabetes mellitus, increased requirements for insulin or oral hypoglycaemic agents in diabetics, hirsutism

Metabolic:

Negative nitrogen balance due to protein catabolism

Cardiovascular:

Myocardial rupture following recent myocardial infarction

Other:

Anaphylactoid or hypersensitivity reactions, thromboembolism, weight gain, increased appetite, nausea, malaise, hiccups