To assess the efficacy and safety of different doses of APD421 in the prevention of
post-operative nausea and vomiting (PONV) in adult patients at moderate to high-risk of PONV.
Patients must be undergoing elective surgery under general anaesthesia (hysterectomy (any
surgical technique), cholecystectomy (any surgical technique) or "other" elective surgery
scheduled to last at least one hour from induction of anaesthesia), requiring at least one
overnight stay in hospital, and have at least 2 of the following risk factors for PONV: Past
history of PONV and/or motion sickness; Non-smoking status; Female gender; Planned opiate use
for post-operative analgesia.