Journal of Pain & Relief
Open Access

Abstract

Pain management with opioids is often limited by adverse effects and sometimes by ineffectiveness in an opioid-tolerant patient. Adjuvant treatment with an inexpensive opioid-sparing drug such as ketamine may help to provide better analgesia with fewer adverse effects. Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, is shown to be useful in a variety of surgical patients. Perioperative ketamine in sub anesthetic doses reduces postoperative opioid requirements, postoperative nausea or vomiting (PONV), rescue analgesic requirements, and pain intensity. Ketamine has multiple mechanisms of action, including but not limited to decreasing central excitability, decreasing acute postoperative opiate tolerance, and a possible modulation of opiate receptors. Adverse effects for perioperative ketamine are mild or absent. Postop pain management can be especially challenging in patients with preexisting chronic pain because of underlying factors such as psychiatric disorders (depression/anxiety), opioid tolerance, and opioid-induced hyperalgesia. Ketamine may be most efficacious in patients who consume higher amounts of preoperative opiate medications. Studies have also shown that ketamine may reduce pain intensity and analgesic consumption up to 6 weeks in the postoperative period. Postsurgical pain typically resolves by 4 weeks and a reduction in pain intensity at 6 weeks would represent a potential reduction in chronic postsurgical pain, an outcome of interest to primary care physicians, surgeons, and anesthesiologists. Evidence suggests that postoperative pain continues to be undermanaged and poorly controlled acute postoperative pain is associated with an increased risk of developing chronic postsurgical pain and cardiopulmonary complications. Multimodal therapy, including opioids, non-opioid adjunctive medications (ketamine, NSAIDs, acetaminophen, and anticonvulsants), along with regional anesthetic techniques may often be required to minimize potential complications related to suboptimal pain management. The presentation will discuss the usefulness of low dose ketamine in the perioperative setting, highlighting its use in the opioid-tolerant patient.

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