Effect of pre-emptive hydromorphone administration on postoperative pain relief--a randomized controlled trial.

Background And Aim Of Study: Pre-emptive analgesia represents a treatment strategy which tries to prevent the development of pain by inhibiting central reactions to peripheral sensory stimuli. In a prospective randomized double-blind placebo-controlled study, the effect of oral premedication with 4 mg of a slow-release hydromorphone preparation on postoperative piritramide consumption and subjective pain perception is being evaluated.

Patients And Methods: 96 women undergoing hysterectomy were randomly assigned to four study groups. Patients from groups 1 and 2 received hydromorphone and placebo respectively two hours before surgery, while those from groups 3 and 4 were given the same substances one hour after the end of the operation. Postoperative pain relief was provided by a patient-controlled infusion pump with piritramide. The intensity of postoperative pain as perceived by the patients was quantified on a visual analogue scale. Piritramide consumption and pain scores were recorded at 1 and 24 hours after surgery. Approval of the local Ethics Committee had been obtained beforehand as well as written informed consent from the patients.

Results: No significant differences in piritramide consumption were observed in between the four study groups. Visual analogue scale (VAS) ratings at 1 and 24 hours after surgery did not show any significant differences either--irrespective of whether the patients had received hydromorphone or placebo preoperatively or postoperatively.

Conclusion: In our study, oral administration of 4 mg of slow-release hydromorphone did not show any greater pre-emptive analgesic effect than placebo.