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The steroid should be started at the same time as the co-trimoxazole or pentamidine and should be withdrawn before the antibiotic treatment is complete.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