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.