الفهرس 
Physicochemical characteristicsOnly 14 pages are availabe for public view
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Abstract
Remifentanil is 4-anilidopiperdine derivatives and a specific p-opioid receptor agonist with potency similar to that of fentanyl and a speed of onset similar to that of alfentanil(ll. However, unlike any other available opioid remifentanil has an ester linkage in its molecular structure. Consequently, it has a very short duration of action because of rapid breakdown of the ester linkage by non-specific plasma and tissue estrases. The time for the plasma concentration to fall by 50% after stopping an i.v. infusion is short compared with that for other opioids”). Remifentanil is metabolized to a relatively inactive metabolite (potency 0.1 - 0.3% compared with parent drug). These pharmacokinetic properties are consistent with a short predictable duration of action and no accumulation even after high doses or prolonged infusion. However, a major disadvantage of remifentanil is the appropriate transition to postoperative pain control, as the rapid offset of action has been shown to produce inadequate postoperative analgesia, which may adversely affect patient recovery and outcome(’). Sevoflurane has a low blood gas solubility coefficient (0.69) and is the least respiratory irritant of the available volatile anesthetics. These properties make sevoflurane an ideal inhalation induction agent(’). Also, propofol is highly lipid soluble which result in a rapid onset, awakening from a single bolus dose is also rapid owing to its very short initial distribution half life (2 - 8 minutes). Recovery from propofol is more rapid and accompanied by less hangover than recovery from methohexical, thiopental or etomidate”). So, sevoflurane and propofol are most popular induction agents available now.