Finally, noting that CES is apparently an effective treatment for pain, several studies have been done to assess its potential to potentiate the effects of analgesics. One anesthetist gave 90 urological patients and 30 abdominal surgery patients N2O (nitrous oxide) in concentrations of 75%, 62.5%, or 50% alone, or in combination with CES during surgery. After 20 minutes patients were given a painful stimulation with Kocker clamps on their inner thigh for one minute. It was found that CES increased the potency of all three levels of N2O by 37%.

In a more elaborate study, 50 patients underwent urological operations with anesthesia induced with doperidol, diazepan, and pancuronium. Half the patients also were given CES treatment during the surgery. Anesthesia was maintained as necessary throughout the surgery by an IV fentanyl drip. Those patients receiving CES required an average of 33% less fentanyl to maintain anesthesia than did those who were not receiving CES.

It was found in both of the above two studies, that analgesia was maintained for a longer period following surgery among those patients receiving CES, than among those who did not.