Nausea and vomiting with use of a patient-controlled analgesia system.

The incidence of nausea and vomiting following patient controlled analgesia and intramuscular morphine injections on demand was compared in a double-blind randomised study of 32 healthy patients undergoing elective cholecystectomy. There were no significant differences between the two groups in mean 24 hour postoperative morphine consumption, subjective experience of pain, nausea and sedation assessed by visual linear analogue scoring, and the postoperative requirements for antiemetic therapy.