Combined routes of administration to assay oral analgesia in postoperative pain.

To increase the sensitivity of the method for evaluating oral analgesics in postoperative patients, we designed a combined oral/parenteral bioassay. Drugs studied were parenteral morphine, parenteral propiram, and oral codeine at two dose levels each and oral propiram at four dose levels. Results from data on 308 patients suggest that future studies designed to establish the relative potencies of oral analgesics should use parenteral morphine as the standard in a combined oral/parenteral study because this approach provides a very sensitive measure of analgesia. Further, with one drug as the reference compound, results from many sources would be more readily compared.