C. Dexamethasone – Explanation

This is clinically relevant as there are some situations where it is important to combine high
glucocorticoid (antiinflammatory) activity with minimal mineralocorticoid (fluid-retention) effects. A
good example is the use of dexamethsone for patients with raised intracranial pressure secondary to
brain tumourse.
Corticosteroids
Corticosteroids are amongst the most commonly prescribed therapies in clinical practice. They are
used both systemically (oral or intravenous) or locally (skin creams, inhalers, eye drops, intraarticular). They augment and in some cases replace the natural glucocorticoid and mineralocorticoid
activity of endogenous steroids

The relative glucocorticoid and mineralocorticoid activity of commonly used steroids is shown below:

Side-effects
The side-effects of corticosteroids are numerous and represent the single greatest limitation on their
usage. Sideffects are more common with systemic and prolonged therapy

Glucocorticoid side-effects

• endocrine: impaired glucose regulation, increased appetite/weight gain, hirsutism, hyperlipidemia
• Cushing’s syndrome: moon face, buffalo hump, striae
• musculoskeletal: osteoporosis, proximal myopathy, avascular necrosis of the femoral head
• immunosuppression: increased susceptibility to severe infection, reactivation of tuberculosis
• psychiatric: insomnia, mania, depression
• gastrointestinal: peptic ulceration, acute pancreatitis
• ophthalmic: glaucoma, cataracts
• suppression of growth in children

Mineralocorticoid side-effects

• fluid retention
• hypertension

Selected points on the use of corticosteroids:

• patients on long-term steroids should have their doses doubled during intercurrent illness
• the BNF suggests gradual withdrawal of systemic corticosteroids if patients have: received more
  than 40mg prednisolone daily for more than one week, received more than 3 weeks treatment or
  recently received repeated courses