Corticosteroid — High Potency Pregnancy: Use only if clearly necessary — crosses placenta; risk of fetal adrenal suppression; adrenal support for neonate

Dexamethasone (Rheumatology)

Brand names: Neofordex, Dexamethasone phosphate

Adult dose

Dose: 0.5–9 mg/day oral; 4–24 mg IV for IV pulse in vasculitis

Route: Oral or Intravenous

Frequency: Once daily (oral); as single or divided daily doses (IV)

Max: 24 mg/day IV (severe vasculitis or GCA with vision loss)

Dexamethasone 0.75 mg ≡ prednisolone 5 mg (glucocorticoid equivalents). No mineralocorticoid activity — useful when fluid retention is a concern. GCA with visual loss: high-dose IV dexamethasone or methylprednisolone 500–1000 mg for 3 days.

Paediatric dose

Dose: 0.15–0.6 mg/kg

Route: Oral or IV

Frequency: Once daily or divided

Max: Specialist guidance — depends on indication

Paediatric rheumatology — under specialist guidance; steroid-sparing strategies preferred for long-term use

Dose adjustments

Renal

No dose adjustment required; monitor fluid balance

Hepatic

No specific adjustment; use with caution in severe hepatic impairment

Paediatric weight-based calculator

Patient weight (kg)

Paediatric rheumatology — under specialist guidance; steroid-sparing strategies preferred for long-term use

Clinical pearls

GCA with visual symptoms: EULAR recommends IV methylprednisolone 500–1000 mg/day for 3 days or equivalent high-dose IV dexamethasone before transitioning to oral prednisolone — do not wait for biopsy results
No mineralocorticoid activity: advantage in patients with heart failure or hypertension — contrast with prednisolone and hydrocortisone which have partial mineralocorticoid activity
MHRA: COVID-19 use — RECOVERY trial (dexamethasone 6 mg/day for 10 days) established its role in hospitalised COVID-19; not a rheumatology use but important context for drug recognition
Dexamethasone is 6–8× more potent than prednisolone (glucocorticoid equivalence): 0.75 mg dexamethasone = 5 mg prednisolone = 4 mg methylprednisolone = 20 mg hydrocortisone
Long half-life (35–54 hours): single daily dosing is standard; once-weekly dexamethasone used in Neofordex for myeloma — do not confuse with rheumatology dosing

Contraindications

Systemic infection without antimicrobial cover
Live vaccines
Hypersensitivity to dexamethasone

Side effects

No mineralocorticoid effects — does not cause sodium retention/oedema (unlike hydrocortisone)
Hyperglycaemia — stronger glucocorticoid effect than prednisolone
Osteoporosis risk with prolonged use
Adrenal suppression
Psychosis and mood disorders — particularly with high-dose IV
Cataracts, glaucoma

Interactions

CYP3A4 inducers (rifampicin) — reduce dexamethasone levels significantly
NSAIDs — increased GI ulceration risk
Antidiabetics — dose adjustment needed
Warfarin — variable effect; monitor INR

Monitoring

Blood glucose
Blood pressure
Bone protection assessment (DXA scan if long-term)
Adrenal function if long-term use and planned tapering
Ophthalmic review (cataract/glaucoma) if prolonged use

Reference: BNFc; BNF 90; RECOVERY Trial (NEJM 2021); EULAR GCA Guidelines 2018; BSR GCA Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways