Intervention: Amisulpride
Trial phase: Phase 2
ATC code: N05AL05
SMILES: CCN1CCCC1CNC(=O)c1cc(S(=O)(=O)CC)c(N)cc1OC
Sex: All
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 50
Group description: 5mg dose level
Eligibility criteria:
Inclusion criteria

Male or female patients ≥ 18 years of age
Ability and willingness to give written informed consent

Patients undergoing elective surgery under general anaesthesia requiring at least one overnight stay in hospital for either:

Hysterectomy (any surgical technique)
Cholecystectomy (any surgical technique)
Other elective surgery requiring overnight admission to hospital and scheduled to last at least 1 hour from induction of anaesthesia

Patients with at least 2 of the following risk factors for PONV:

Past history of PONV and/or motion sickness
Habitual non-smoking status
Female sex
Expected to receive opioid analgesia post-operatively
American Society of Anesthesiologists (ASA) risk score I-III

Adequate cardiac, hepatic and renal function

QTc interval < 500 ms
Alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) < 5 x upper limit normal (ULN)
Bilirubin < 3 x ULN
Creatinine < 2 x ULN

Adequate haematological function

Haemoglobin ≥ 9 g/dL
White blood count ≥ 3.0 x 109/L
Platelet count ≥ 100 x 109/L
For females of child-bearing potential: ability and willingness to use a highly effective form of contraception (e.g., abstinence from sexual intercourse, surgical sterilisation (of subject or partner) or a double-barrier method of contraception such as either an intra-uterine device (IUD) or an occlusive cap with spermicide, in conjunction with partner's use of a condom) between the date of screening and at least 48 hours after administration of study drug.

Exclusion Criteria

Patients undergoing outpatient/day case surgery
Patients undergoing surgery where the patient is expected to remain ventilated for a period after surgery
Patients undergoing intra-thoracic, transplant or central nervous system surgery
Patients receiving a local anaesthetic/regional neuraxial (intrathecal or epidural) block
Patients who are expected to need a naso- or oral-gastric tube in situ after surgery is completed
Patients receiving the active ingredient of APD421 for any indication within the last 2 weeks
Patients who are allergic to the active ingredient or any of the excipients of APD421
Patients with a pre-existing vestibular disorder or history of dizziness
Patients with pre-existing nausea or vomiting in the 24 hours before surgery
Patients treated with regular anti-emetic therapy including corticosteroids
Patients being treated with medications which could induce torsades de pointes, including Class Ia antiarrhythmic agents such as quinidine, disopyramide, procainamide; Class III antiarrhythmic agents such as amiodarone and sotalol; and other medications such as bepridil, cisapride, thioridazine, methadone, IV erythromycin, IV vincamine, halofantrine, pentamidine, sparfloxacin
Patients being treated with levodopa
Patients who are pregnant or breast feeding
Patients with a history of alcohol abuse
Patients with pre-existing, clinically significant cardiac arrhythmia
Patients diagnosed with Parkinson's disease
Patients who have received anti-cancer chemotherapy in the previous 4 weeks
Patients with a history of epilepsy
Any other concurrent disease or illness that, in the opinion of the investigator makes the patient unsuitable for the study
Patients who have participated in a previous study within the last 28 days (French sites only: Patients who have participated in a previous study within the last 6 months, if required by national or local regulations)