Determination of the Potency of Remifentanil Compared with Alfentanil Using Ventilatory Depression as the Measure of Opioid Effect

Abstract

Based on depression of the minute ventilatory response to 7.5% CO2, remifentanil is approximately 40 (26-65) times more potent than alfentanil when remifentanil and alfentanil whole-blood concentrations are compared. As alfentanil is usually measured as a plasma concentration, remifentanil is approximately 70 (41-104) times more potent than alfentanil when remifentanil whole-blood concentration is compared with alfentanil plasma concentration. This information should be used when performing comparative studies between remifentanil and other opioids.