ABSTRACT
Post-operative nausea and vomiting (PONV) is a common side effect following anaesthesia. It can be very upsetting for patients and in severe cases may cause more distress than post-operative pain. If prolonged, PONV can cause electrolyte imbalances and dehydration. Anaesthetists assess individual patients at the preoperative visit and make a note of factors that might increase their risk of PONV. Broadly categorised, these risks can be grouped into patient factors, surgical factors and anaesthetic factors. Serotonin antagonists are a popular choice of anti-emetic, both as a prophylaxis and as a treatment of PONV. Stimuli for nausea and vomiting come from many sources including the gastrointestinal tract, the chemoreceptor trigger zone, the vestibular system and higher centres of the brain. The anti-muscarinics are the oldest class of anti-emetic but were initially used in anaesthesia to block the vagal side effects of chloroform and to dry secretions.
