Dexamethasone

Dexamethasone - has very high glucocorticoid activity and insignificant mineralocorticoid activity, making it particularly suitable for conditions where water retention would be a disadvantage.Adjuvant corticosteroid has been shown to improve survival in Pneumocystis carinii pneumonia.

Uses:
Nausea
Cerebral oedema
Laryngeal oedema
Adjunct in Pneumocystis carinii pneumonia (see co-trimoxazole and
pentamidine)
Bacterial meningitis, particularly where pneumococcal suspected

Contraindications:
Systemic infection (unless specific anti-microbial therapy given)

Administration:
• Cerebral oedema
   IV bolus: 8 mg initially, then 4 mg 6 hourly as required for 2–10 days
• Pneumocystis carinii pneumonia
  IV bolus: 8 mg 6 hourly 5 days, then dose reduced to complete 21 days of treatment

The steroid should be started at the same time as the co-trimoxazole or pentamidine and should be withdrawn before the antibiotic treatment is complete.

How not to use dexamethasone:
Do not stop abruptly after prolonged use (adrenocortical insufficiency)

Adverse effects
Perineal irritation may follow IV administration of the phosphate ester Prolonged use may also lead to the following problems:
• increased susceptibility to infections
• impaired wound healing
• peptic ulceration
• muscle weakness (proximal myopathy)
• osteoporosis
• hyperglycaemia

Cautions
Diabetes mellitus
Concurrent use of NSAID (increased risk of GI bleeding)