action activity acute administration agents agonist analgesia Anesth Analg anesthesia Anesthesiology anesthetic antagonists arterial associated atrial binding block blockade blood flow blood pressure body brain calcium cardiac cardiac output cause cell central cerebral changes channels chronic clearance clinical compared concentration decrease depression disease dose drug duration effects Eger et al failure fentanyl Figure fluid function glucose half-life heart heart rate hepatic increase induced infusion inhaled inhibition injection intracranial pressure isoflurane ketamine kidney lead less levels lidocaine mechanism membrane metabolism minutes morphine muscle myocardial myocardial infarction nerve nervous system normal occur opioid oral pain patients perioperative peripheral Pharmacokinetics plasma plasma concentrations postoperative potential prevent produce prolonged propofol protein pulmonary rapid receptors reduced reflect release renal resistance response result risk sevoflurane side effects sodium spinal stimulation surgery sympathetic Table therapy tion tissue treatment vascular ventricular volatile volume