Pain following craniotomy: a preliminary study comparing PCA morphine with intramuscular codeine phosphate.

We have performed a prospective randomised trial of 30 patients undergoing craniotomy to compare intramuscular codeine phosphate with patient-controlled analgesia using morphine 1 mg bolus with a 10-min lockout and no background infusion. For 24 h postoperatively, pain, nausea, Glasgow coma score, respiratory rate and sedation score were assessed. There was a wide variation in the amounts of morphine requested by the patients in the patient-controlled analgesia group in the first 24 h postoperatively (range 2-79 mg, median 17 mg). There was a small, but non-significant, reduction in pain scores in the patient-controlled analgesia group. There were no significant differences between the two groups in respect of nausea and vomiting, sedation score or respiratory rate. No major adverse effects were noted in either group. Patient-controlled analgesia with morphine is an alternative to intramuscular codeine phosphate in neurosurgical patients which merits further investigation.