Ketamine
Anesthesia & Analgesia November 1, 1998 Rainer Kohrs, Marcel E. Durieux 610 citations
Ketamine is a unique anesthetic that induces a dissociative state with profound analgesia and amnesia without necessarily causing loss of consciousness. Introduced over 30 years ago as a potential 'monoanesthetic,' its use diminished due to side effects like psychotomimetic reactions, but it remains valuable for specific indications such as induction in hemodynamic shock or asthma, and sedation for painful procedures. Its primary mechanism is noncompetitive antagonism of NMDA glutamate receptors, though it also interacts with opioid, cholinergic, and monoaminergic systems. The S(+) enantiomer has greater potency and may offer faster recovery and fewer side effects than the racemic mixture. Small doses provide preemptive analgesia, reducing postoperative opioid requirements by 40-60%. Ketamine may also have neuroprotective properties, and concerns about increasing intracranial pressure are mitigated by maintaining normocapnia.