Antiemetic efficacy of combination Cyclizine-Morphine patient controlled analgesia in postoperative major gynaecological surgery patients

INTERVENTION: Compare the efficacy of combination morphine plus cyclizine patient controlled analgesia (PCA) versus morphine alone in PCA in patients undergoing major gynaecological surgery following a single prophylactic intravenous dose of cyclizine in theatre. CONDITION: Surgery: Gynaecological ; Surgery ; Surgery: Gynaecological PRIMARY OUTCOME: Assessment of nausea and vomiting, pain scores, morphine requirements, sedation, the need for rescue antiemetic medication, incidence of side effects SECONDARY OUTCOME: Not provided at time of registration INCLUSION CRITERIA: 90 subjects will be recruited in total, between 18‐65 years old.