This guideline is aimed at providing quick and general guideline on PONV. Refer to local protocols for more detailed guidance.
Nausea and vomiting is a common and distressing symptom or side effect in medicine, surgery and following anaesthesia. It can cause complications such as wound dehiscence, electrolyte imbalance, increased pain, dehydration and aspiration. Generally, uncomplicated PONV rarely goes beyond 24 hours post-operatively. Problematic PONV however is more multifactorial in origin and can be difficult to treat effectively. Patients at risk of this should be identified by the anaesthetist and may be given prophylactic anti-emetic treatment. Post-operative patients with nausea and vomiting may be considered as either failure of prophylaxis or for primary treatment.
The table below is a general quick guide on the prescribing of anti-emetics, but see local guidelines.
|Anti-emetic / Site of action
|Dose and route of administration
5HT3 receptor antagonist
|4mg oral / IV every 8 hours
Risk of prolonged QT interval, constipation.
Avoid if congenital long QT syndrome.
Medullary chemoreceptor zone
Dopamine (D2) receptor antagonist
3–6mg buccal every 12 hours or 12.5mg deep IM as a 'one-off' dose (IM route only, not by other parenteral routes).
In elderly patients - 3mg buccal every 12 hours or 6.25mg IM as a 'one-off' dose.
Extrapyramidal side effects - dystonic reaction.
Dose reduce in elderly patients due to increased susceptibility to hypotension and neuromuscular reactions.
Acts on vomiting centre.
Histamine (H1) receptor antagonist
50mg oral/IM/IV every 8 hours. Avoid oral route if actively vomiting.
In elderly patients - 25mg every 8 hours.
Avoid in severe heart failure, porphyria.
Site of action unknown
|4mg IV/IM single dose
Restricted for use by the acute pain team, on-call anaesthetist.
Caution - acute rectal pain with IV administration.
It is not licensed for PONV.
Mainly dopaminergic receptor antagonist in chemoreceptor trigger zone
|IV dose varies – see BNF for guidance
Restricted to use by consultant anaesthetists. Third-line agent for PONV if unresponsive to other anti-emetics.
Risk of QT interval prolongation.
|N.B. The side effects, cautions and contraindications mentioned in the comments section are not exhaustive. See BNF or Summary of Product Characteristics for further information.
Guideline last reviewed and updated November 2020