Comparison of infusions of morphine and lysine acetyl salicylate for the relief of pain following thoracic surgery.

A double-blind study comparing the effectiveness of a continuous infusion i.v. of lysine acetyl salicylate (LAS) with an infusion of morphine for the treatment of pain following pulmonary surgery is described. Mean pain scores in the two groups were not significantly different at any stage during the 24-h period of study. LAS was not associated with any significantly greater blood loss in the period after operation. The incidence of drowsiness, nausea and vomiting, and the need for antiemetic medication were similar in both groups.