Clinical pharmacology of opioids: pharmacokinetic and pharmacodynamic aspects

Several authors have measured the pharmacokinetic parameters of opioids as they relate to specific pharmacodynamic features intraoperatively (movement with skin incision, autonomic reactivity, rigidity) and postoperatively (analgesia). Noninvasive techniques of administering lipid-soluble opioids, including transdermal (passive and iontophoretic) and intranasal are also currently under investigation. The controversy regarding epidural versus intravenous administration of lipid-soluble opioids has continued in the recent literature. The increased interest in intrathecal morphine has prompted several dose-response studies which are discussed.