Ketamine for Chronic Non-Cancer Pain: A Review of Clinical Effectiveness, Cost-Effectiveness, and Guidelines [Internet]

Excerpt

In Canada, about one in five adults older than 18 years of age live with chronic pain. Pain can be sub-defined by three main biological mechanisms: 1) Nociceptive pain (from damage to body tissue, as in injury, disease or inflammation); 2) Neuropathic pain (from direct damage of the nervous system); and 3) Nociplastic pain (from a change in sensory neurons function). Chronic pain is associated with significant emotional distress, like anxiety, anger, frustration and depression, and is recognized by the World Health Organization as a disease by itself listed in the International Classification of Disease version 11. Treatment and management of chronic pain are complex and difficult, involving multiple interventions, including pharmacological and psychological interventions. Pharmacological interventions considered for chronic pain include nonopioid analgesics (e.g., nonsteroidal anti-inflammatory drugs, acetaminophen), antidepressants, antiepileptic drugs, other adjuvant medications (e.g., topical agents, cannabis and cannabinoids), opioid, and infusion therapies (e.g., ketamine, lidocaine).

Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist, has been approved and primarily used as an anesthetic induction agent in doses ranging between 1 and 4.5 mg/kg. As it also interacts with other receptors, ketamine has been explored for other indications such as depressive disorders, suicidal ideation, substance-use disorders, anxiety disorders, refractory status epilepticus, bronchial asthma exacerbations, and pain management. In hospital and emergency department, ketamine has been used for pain management of acute conditions such as burns, trauma, or post-operative pain. Recently, intravenous (IV) ketamine infusions has been increasingly used as a treatment option for acute pain as well as chronic non-cancer pain such as complex regional pain syndrome (CRPS), neuropathic pain, and other refractory chronic pain conditions. Despite potential opportunities of ketamine for numerous indications, the use of ketamine is known to be associated with psychotomimetic effects such as euphoria, dysphoria, psychomotor retardation, hallucinations, vivid dreams, and nightmares, as common side effects. Given the availability of ketamine of different formulations and its potential opportunities in pain management, there is a need to determine its benefits and risks in the treatment of chronic pain.

The aim of this report is to review the evidence regarding the clinical effectiveness and cost-effectiveness of ketamine for treating chronic non-cancer pain in adults. This report also aims to review the evidence-based guidelines regarding the use of ketamine for chronic non-cancer pain.

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