Remifentanil is in the same structural family as fentanyl and the other phenylpiperidines. It is a novel, short-acting mu-receptor opioid agonist. Although it is a member of the 4-anilidopiperidine class, it is unique among the currently marketed agents because of its ester structure. Consequently Remifentanil undergoes widespread extrahepatic metabolism by blood and tissue nonspecific esterases, resulting in an extremely rapid clearance of approximately 3 L/min. Like the other members of this class of drugs, remifentanil is lipophilic and is widely distributed in body tissues with a steady-state volume of distribution of approximately 30L. Because of its unique metabolic pathway (among this group of drugs) and rapid clearance, remifentanil represents a new pharmacokinetic class of opioid. Unlike the other fentanyl congeners, termination of the therapeutic effect of remifentanil mostly depends on metabolic clearance rather than on redistribution. The context-sensitive half- time is strikingly short for remifentanil, and this is perhaps the most compelling evidence of the pharmacokinetic singularity of the drug.
Pharmacodynamically, remifentanil is similar to the other fentanyl congeners. The drug produces physiological changes consistent with potent mu-receptor agonist activity, including analgesia and sedation. Its adverse effect profile (like that of the other drugs of this class) includes ventilatory depression, nausea, vomiting, muscular rigidity, bradycardia and pruritus. Because it does not release histamine upon injection, remifentanil has fewer hemodynamic adverse effects than morphine. The therapeutic potency of remifentanil is somewhat less than that of fentanyl, with an effective concentration (producing 50% of maximal effect, as measured by electroencephalography) of approximately 10 to 20 mg/L. Onset of effect is very rapid and is similar to that of alfentanil.
Storage conditions: Room temperature
Packaging: glass vial