Ketamine as an adjunct to patient-controlled analgesia: why, for whom, and how much?

Excerpt

Ketamine is a phenylpiperidine derivative that has been available for over six decades. For many years, it has been used to provide analgesia and anesthesia in battlefield and emergency room settings, not to mention in veterinary medicine. Though its role as an anesthetic agent in the operating room is well known, its use has arguably been on the decline, in part because of its psychotropic and sympathomimetic adverse effects. Nevertheless, a resurgence in its use is now being seen, in some measure due to its multimodal mechanisms of analgesia: antagonism of N-methyl-D-aspartate (NMDA) excitatory glutamate receptors that play a prominent role in facilitating nociceptive transmission; enhancement of descending inhibition, and anti-inflammatory effects in the central nervous system.1-3 As a result, ketamine has now been increasingly used for a range of effects, including antinociceptive effects for treating pain in its various forms (acute, chronic, neuropathic, cancer-related) as well as for addressing treatment-resistant depression.4,5 …