Remifentanil.

Remifentanil is a new selective mu opioid receptor agonist of higher potency than alfentanil, with pharmacological effects that essentially parallel those of alfentanil and other opioids in this class. Unlike other opioids, remifentanil is rapidly hydrolysed by nonspecific plasma and tissue esterases: this imparts brevity of action, precise and rapidly titratable effects (due to rapid onset and offset), non-cumulative opioid effects and rapid recovery after cessation of administration. The onset of action of remifentanil is similar to that of alfentanil, although its offset is considerably more rapid and independent of the duration of infusion. Remifentanil also has a sparing effect on hypnotics and sedatives. Its brevity of action ensures not only a rapid resolution of adverse effects but also a rapid offset of analgesic effect. Therefore, appropriate postoperative analgesia, when necessary, should be established before discontinuation of remifentanil infusion. The unique pharmacokinetic profile of remifentanil facilitates 'real time' management of intraoperative stress, as well as provision of optimal intraoperative analgesia without compromising recovery for a variety of surgical procedures.