Dexamethasone

Indications

Dexamethasone is used for: Shock, Bronchial asthma, Status asthmaticus, Rheumatoid arthritis, Gout, Severe allergies, Skin diseases, Hyperpyrexia, Bacteraemia, Toxaemia, Acute adrenocortical insufficiency, Cortisosteroid-responsive dermatoses, Eczema, Urticaria, Cerebral oedema, other indications where glucocorticoid therapy is required.,

Adult Dose

Oral Anti-inflammatory Adult: 0.75-9 mg daily in 2-4 divided doses; Screening test for Cushing's syndrome Adult: 0.5 mg every 6 hr for 48 hr after determining baseline 24-hr urinary 17-hydroxycorticosteroid (17-OHCS) concentrations. During the second 24 hr of dexamethasone admin, urine is collected and analysed for 17-OHCS. Alternatively, after a baseline plasma cortisol determination, 1 mg may be given at 11 pm and plasma cortisol determined at 8 am the next morning. Plasma cortisol and urinary output of 17-OHCS are depressed after dexamethasone admin in normal individuals but remain at basal levels in patients with Cushing's syndrome. Acute exacerbations in multiple sclerosis Adult: 30 mg daily for 1 wk followed by 4-12 mg daily for 1 mth.

Child Dose

Oral Anti-inflammatory Child: 1 mth-18 yr: 10-100 mcg/kg daily in 1-2 divided doses via oral admin, adjusted according to response; up to 300 micrograms/kg daily may be used in emergency situations. Acute exacerbations in multiple sclerosis Child: 1 mth-12 yr: 100-400 mcg/kg daily in 1-2 divided doses; 12-18 yr: Initially 0.5-24 mg daily. Max. 24 mg daily.

Renal Dose

Administration

Should be taken with food.

Contra Indications

Ocular herpes simplex is an example of absolute contraindication to corticosteroid therapy. Relative contraindications are: Gastrointestinal ulcer, acute or chronic infections, osteoporosis, pregnancy, diabetes mellitus, renal insufficiency, hypertension, history of psychotic illness, immediate before prophylactic immunization and finally hypersensitivity to Dexamethasone.

Precautions

Dexamethasone should be used with caution in the presence of congestive heart failure or hypertension, in patients with diabetes mellitus, epilepsy, glaucoma, infectious disease, chronic renal failure and uraemia and in elderly persons. Lactation: Drug excreted in breast milk; not recommended

Pregnancy-Lactation

Interactions

Increased risk of hypokalaemia when used concurrently with potassium-depleting drugs such as amphotericin B and loop diuretics. Reduces efficacy of isoniazid, salicylates, vaccines and toxoids. Increased activity of dexamethasone and cyclosporin when used together. Concurrent use with aspirin or ethanol may lead to increased GI side effects. Potentially Fatal: Reduced efficacy in combination with ephedrine, cholestyramine, phenytoin, phenobarbital and rifampicin.

Adverse Effects

Side effects of Dexamethasone : Acne,Adrenal suppression,Arrhythmia,Bradycardia,Cardiac arrest,Cataracts,Change in spermatogenesis,Delayed wound healing,Depression,Diabetes mellitus,Diaphoresis,Emotional instability,Erythema,Euphoria,Exophthalmos,GI perforation,Glaucoma,Glucose intolerance,Glucosuria,Hepatomegaly,Hypokalemic alkalosis,Increased intracranial pressure,Increased transaminases,Insomnia,Kaposi's sarcoma,Menstrual irregularity,Moon face,Myopathy,Neuritis,Osteoporosis,Peptic ulcer,Perianal pruritus,Petechia,Perianal pruritus,Pituitary adrenal axis suppression,Pseudotumor cerebri (on withdrawal),Psychosis,Pulmonary edema,Rash,Seizure,Spermatogenesis altered (increased or decreased),Ulcerative esophagitis,Urticaria,Vertigo,Weight gain

Mechanism of Action

Dexamethasone is a synthetic glucocorticoid which decreases inflammation by inhibiting the migration of leukocytes and reversal of increased capillary permeability. It suppresses normal immune response.