Ketamine, an NMDA receptor antagonist, is integral to multimodal pain management strategies for its ability to reduce acute post-surgical pain and opioid requirements. Its utility extends to diminishing opioid tolerance postoperatively and enhancing analgesia in combination with opioids, NSAIDs, and acetaminophen. Studies, including those by Loftus et al. and Nielsen et al., demonstrate ketamine's effectiveness in decreasing postoperative opioid consumption and long-term pain relief, particularly notable in opioid-dependent patients and those undergoing surgeries like spinal fusion.
Administered in sub-anesthetic doses, ketamine's analgesic benefits are achieved with bolus doses up to 0.25 mg/kg to avoid tachycardia and hypertension, considering its 2-3 hour half-life. Doses exceeding this, particularly in patients with coronary artery disease, may increase the risk of myocardial ischemia. Besides its analgesic properties, ketamine addresses neuropathic pain and has shown antidepressant effects. However, higher doses risk dysphoric syndromes, hallucinations, and out-of-body experiences, which can be mitigated with benzodiazepines but are best avoided by not exceeding 0.5 mg/kg doses. Despite its advantages, ketamine's high addictive potential cautions its use, emphasizing its role in reducing opioid side effects without necessarily addressing the broader issue of prescription drug abuse.
