Epidural clonidine decreases postoperative requirements for epidural fentanyl.

Objective. This study assesses the possibility that clonidine may decrease analgesic opioid demand in postoperative patients. Methods. Twenty-five patients were allocated randomly after abdominal surgery to receive either an epidural bolus dose of fentanyl (1.0 mcg.kg −1 ) followed by a 1.0 mcg.kg −1 h −1 continuous epidural infusion, or an epidural bolus dose of fentanyl (1.0 mcg.kg −1 ) followed by a continuous epidural infusion combining fentanyl 0.5 mcg.kg −1 .h −1 and clonidine 0.3 mcg.kg −1 .h −1 . Pain was assessed at definite intervals on a visual analog scale (VAS) over 3 postoperative days. Epidural infusion was halved when VAS score was lower than 2. Patients were monitored with a pulse oxymeter over 12 hours during the first postoperative night. Plasma fentanyl was measured by radioimmunoassay when patients left the recovery room and at 8 a.m. on the first and the second postoperative days. Results. VAS scores were comparable in the two groups of patients. The amount of fentanyl delivered was significantly lower in the fentanyl + clonidine group, as were the plasma fentanyl concentrations. The duration of SaO 2 Conclusions. The combination of clonidine to epidural fentanyl allows a decrease in opioid requirements without impairing analgesia. Reduction of opioids administration may have beneficial effects on respiratory function in postoperative patients.