Masui. The Japanese journal of anesthesiology
-
Review Comparative Study
[Pharmacodynamics and pharmacokinetics of remifentanil: overview and comparison with other opioids].
In this review, the authors tried to summarize the characteristics and main differences of remifentanil with other opioids, and to overview its pharmacodynamics and pharmacokinetics. Clearance and volume of distribution of remifentnail are extremely different from other conventional opioids. ⋯ As remifentanil is metabolized by a non-specific esterase, excretion of remifentnil is predictable in basically all patients undergoing general anesthesia and surgery. Therefore, remifentanil is considered to be an optimal opioid as an analgesic combined either with inhalational anesthetics or intravenous hypnotics in balanced general anesthesia.
-
Comparative Study
[Postoperative nausea and vomiting after laparoscopic cholecystectomy under total intravenous anesthesia using propofol combined with fentanyl or pentazocine].
The aim of this study was to compare the incidence of postoperative nausea and vomiting (PONV) in propofol-anesthetized patients receiving either fentanyl or pentazocine as opioid supplement. ⋯ The incidence of PONV in propofol-anesthetized patients receiving pentazocine as opioid supplement is not different from that in patients receiving fentanyl.
-
Remifentanil is bound strongly to the mu-opioid receptor and less to the delta - and kappa -receptors. It has pharmacodynamic properties like those of fentanyl and its derivatives. Remifentanil is not bound significantly to any other non-opioid receptors and is competitively antagonized by naloxone. ⋯ These characteristics must be very convenient for the anesthesia technique of ambulatory surgery. However, on the opposite side, we should consider the management of postoperative pain for the patient after the remifentanil anesthesia. These topics on the characteristics of remifentanil and its future are discussed by the experts among Japanese anesthesiologists.
-
Remifentanil has short half-lives: the values of alpha and beta decay are about 2 and 15 min, respectively. Therefore, the time for remifentanil concentration to reach its steady state concentration (Css) is shorter than those of other anesthetic drugs such as propofol and fentanyl. The Css and the time course of plasma concentration as well as effect-site concentration (Ce) during the continuous infusion of remifentanil could be helpful in our clinical practice. ⋯ However, remifentanil concentration does not reach the Css immediately with constant rate infusion. For example, it will take about 5 min for remifentanil effect-site concentration to decrease from Css to a half of Css. It is considered that anesthetic management with remifentanil is superior to that without it.
-
Anesthesia with remifentanil can be induced either with slow bolus administration (1 microg x kg(-1) for over 60 sec) or with starting the continuous infusion (0.5-1 microg x kg(-1) x hr(-1)) combined with a standard hypnotic agent (i.e. propofol, thiamylal, sevoflurane or isoflurane). According to the patient's requirement observing hemodynamics, the infusion rate of remifentanil should be titrated after tracheal intubation. Because of the rapid onset and short duration of its action, the infusion rate can be increased or decreased safely. ⋯ Remifentanil seems to be as potent as fentanyl. Prior to emergence from general anesthesia using remifentanil, postoperative pain management should be considered. NSAIDs or a long acting opioid could be administered.