Chronic pain, defined as pain that persists for more than three months, affects millions of people worldwide and can severely impact daily activities and quality of life. For those seeking relief, innovative treatments like ketamine infusion for chronic pain have emerged as a promising option. This therapy has shown potential in providing significant pain reduction and improving the overall well-being of individuals living with chronic pain conditions.

The manifestation of pain itself typically involves the peripheral and central nervous systems. Pain can be classified as nociceptive, neuropathic, or nocicplastic in origin. Nociceptive pain, also known as physiologic pain, results from the activation of primary nociceptive afferents by actual or potential tissue-damaging stimuli. In nociceptive pain, large nerve integrity remains preserved as sensory receptors are stimulated within visceral and somatic structures. In contrast to nociceptive pain, neuropathic pain results from direct injury or disease affecting the somatosensory system and tends to be more disabling than nociceptive pain.

Recently, the International Association for the Study of Pain added a third category to the pain classification of taxonomy for conditions that do not neatly fit into neuropathic or nociceptive categories. Nociplastic pain refers to pain that arises from altered nociception despite no clear evidence of actual or threatened tissue damage or evidence of a disease or lesion directly affecting the somatosensory system. Conditions considered to be nocicplastic pain include fibromyalgia, complex regional pain syndrome (CRPS) type I, and irritable bowel syndrome (IBS). Chronic pain may also stem from psychological states and does not serve an apparent biological purpose. Unlike the self-limited nature of acute pain, chronic pain often does not have a recognizable endpoint.