Corticosteroid (Antiemetic)

Dexamethasone (PONV Prevention)

Brand names: Dexamethasone (generic)

Dexamethasone is a long-acting corticosteroid given as a single intravenous dose at induction of anaesthesia to prevent postoperative nausea and vomiting, often combined with another antiemetic.

Dosing — not shown for this use

The product information we hold does not support a dose for this page's specific use, route or population, so none is shown. Follow your local or national guideline, and confirm against the product SmPC.

Clinical monograph

How it works

Its precise antiemetic mechanism is unclear but is thought to involve central anti-inflammatory and prostaglandin-modulating effects; it also has analgesic-sparing properties.

Prescribing in practice

A single perioperative dose causes a transient rise in blood glucose, so anticipate and monitor hyperglycaemia particularly in patients with diabetes.
Rapid intravenous injection can cause an unpleasant transient perineal or genital sensation, so give slowly after induction.
Even a single dose is best avoided or used cautiously where there is active untreated systemic infection.

Monitoring

Monitor postoperative nausea and capillary blood glucose, especially in patients with diabetes or impaired glucose tolerance.

Counselling the patient

This single dose is given during your anaesthetic to help prevent sickness afterwards.
Your blood sugar may be checked, particularly if you have diabetes.

Evidence & guidelines

Single-dose dexamethasone for PONV prophylaxis is endorsed by consensus antiemetic guidelines and supported by multiple randomised trials.

Reference: Apfel CC et al PONV Risk Score; SAMBA PONV Guidelines 2020; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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