Use of clonidine in hernia patients: intramuscular versus surgical site

This study was designed to determine if administration of clonidine in hernia patients enhances analgesia. It was also designed to determine whether administration directly in the surgical site further improves the analgesia.

A randomized, double-blinded study was undertaken at a tertiary care hospital. Forty-five outpatients undergoing unilateral inguinal hernia repair by one of two surgeons (D.P. or M.A.) under local anesthesia with monitored anesthesia care were evaluated. Patients were invited to participate in this investigation at the time of the preoperative surgical visit. Patients who had a contraindication to the use of clonidine or who refused repair under local anesthesia with sedation were excluded. Patients were randomized to one of three groups: (a) clonidine 0.5 microg/kg intramuscularly and saline in the surgical site (mixed with the local anesthetic); (b) clonidine 0.5 microg/kg in the surgical site and saline intramuscularly; or (c) saline in both the surgical site and intramuscularly. The outcome measures included visual analog pain scores twice in the hospital, pain scores at rest and with movement 24 hours postoperatively, the time to first analgesic, and total analgesic requirement.

The pain scores were lower in both clonidine groups at 2 hours postoperatively than in the control group (P < .03). No difference was observed with respect to the time to first analgesic, 24-hour analgesic use, or 24-hour pain scores among the groups.

When clonidine is administered to patients undergoing hernia repair, the 2-hour pain scores are lowered. No difference was exhibited when clonidine was administered intramuscularly or directly into the hernia site.