Pharmacokinetics of Fentanyl in Patients Undergoing Abdominal Aortic Surgery

Naloxone reversal of opioid anesthesia revisited: clinical evaluation and plasma concentration analysis of continuous naloxone infusion after anesthesia with high-dose fentanyl

“…2) demonstrated that the plasma fentanyl levels exceeded 10 ng·ml Ϫ1 on average throughout the surgical procedures and decreased with a t1/2 of 6.5 Ϯ 3.2 h after terminating the administration. The present t1/2 values were within the range (5-8 h) reported in previous investigations of high-dose fentanyl anesthesia [17][18][19]. Although fixed-dose studies have failed to demonstrate the minimally effective dose for opioids [5,6], it has generally been accepted that a dose range of 50-150 µg·kg Ϫ1 and a plasma concentration range of 10-15 ng·ml Ϫ1 are required to accomplish satisfactory hemodynamic control using single-agent anesthesia with fentanyl in cardiac surgery [5,6,13].…”

Management of Postoperative Analgesia in Elderly Patients

“…The American Geriatrics Society has for several years been developing guidelines for the exchange of information between physicians of many specialties such as general surgery, orthopedic surgery, physical medicine, rehabilitation, and anesthesiology. 102 Research and education about pain management in the elderly patients should be one of the main priorities in medicine worldwide.…”

“…[98][99][100][101] Moreover, PCA fentanyl seems to produce less impairment of postoperative cognitive function compared with PCA morphine among elderly patients. 69 However, fentanyl accumulates in skeletal muscle and fat 102 and then is slowly released into the blood. 103 The clearance is also delayed in elderly.…”

The effect of acutely induced hepatic failure on remifentanil and fentanyl blood levels in a pig model

“…Although the clearance of fentanyl is liver-dependent its disposition appears to be unaffected by hepatic cirrhosis [14,19]. However, changes in pharmacokinetic parameters (clearance, half-life) may be observed with severe hepatic dysfunction or other conditions altering hepatic blood flow [20].…”