Department of Internal Medicine, China Medical College Hospital, Taichung, Taiwan.

Fifty-nine patients underwent consecutive colonoscopic examination with premedication of electroacupuncture analgesia (EA) were compared with conventional meperidine analgesia (MA) in pain relief and changes of neurotransmitters in serum. The results showed that analgesic efficacy of both groups were the same but with less side effects in the EA group (P < 0.01) especially in regard to dizziness. Serum concentration of beta-endorphin in both groups has a similar curve change at 4 different phases during colonoscopy. Serum concentration of epinephrine, norepinephrine, dopamine and cortisol showed no significant difference between these two groups. The analgesic effect of EA and MA during colonoscopic examination may be closely related to beta-endorphin production in serum.