Dexamethasone

How it works

It binds glucocorticoid receptors to exert powerful anti-inflammatory and immunosuppressive effects and stabilises the blood-brain barrier, reducing peritumoural oedema; it has negligible mineralocorticoid activity.

Prescribing in practice

• Do not stop abruptly after more than a short course, as adrenal suppression risks an adrenal crisis; dosing should be tapered and a steroid emergency card issued.
• Co-prescribe gastroprotection where indicated and monitor for hyperglycaemia, neuropsychiatric effects and increased infection risk during treatment.
• Give doses earlier in the day to limit insomnia and counsel on raised blood glucose, mood changes and proximal myopathy with prolonged use.

Monitoring

Monitor blood glucose, blood pressure, weight, mood and signs of infection during treatment, with bone and gastrointestinal protection considered for prolonged courses.

Counselling the patient

• Never stop the steroid suddenly and carry a steroid alert card.
• Report mood changes, marked thirst, infection symptoms or indigestion.
• Take in the morning to reduce difficulty sleeping.

Evidence & guidelines

Adjunctive dexamethasone improves outcomes in bacterial meningitis in appropriate patients, and it is a long-standing standard treatment for symptomatic cerebral oedema from intracranial tumours.