Duration of action of fentanyl

Abstract

Forty four patients who underwent aortocoronary saphenous vein bypass grafts with cardiopulmonary bypass were studied. The only drug varied was the analgesic supplement in alternate patients. Fentanyl was administered as clinically indicated to a maximum dose of 0.015 mg/kg, morphine to a maximum of 1.0 mg/kg. Based on these data, the relative potency of fentanyl in relation to morphine when used as an anesthetic supplement is 1:77. The duration of action of morphine is two to three times that of fentanyl.