Pharmacokinetic and pharmacodynamic interactions between opioids and propofol

The pharmacokinetic and pharmacodynamic interactions between opioids and propofol increasingly have been described and used in clinical practice. It is now known that propofol inhibits both alfentanil and sufentanil metabolism, thereby increasing the plasma concentrations of these opioids, while alfentanil also elevates propofol concentrations. Pharmacodynamically the interaction between propofol and the opioids is generally found to be synergistic. From the interaction data, the optimal propofol concentrations have been extracted that assure adequate anesthesia and the most rapid recovery possible. In the presence of fentanyl, sufentanil, and alfentanil, the optimal propofol concentration is approximately 3.5 microgram/ml, whereas in the presence of remifentanil, lower propofol concentrations of 2.5 to 3 microgram/ml are required.