Korean J Pain 2019; 32(1): 3-11
Published online January 28, 2019 https://doi.org/10.3344/kjp.2019.32.1.3
Copyright © The Korean Pain Society.
Sang Wook Shin1, Jin Seong Lee2, Salahadin Abdi3, Su Jung Lee1, and Kyung Hoon Kim1*
1Department of Anesthesia and Pain Medicine, Pusan National University, Busan, Korea.
2Department of Psychiatry, Pusan National University, Busan, Korea.
3Department of Pain Medicine, Division of Anesthesia and Critical Care, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Correspondence to: Kyung Hoon Kim. Pain Clinic, Pusan National University Yangsan Hospital, 20 Geumo-ro, Mulgeum-eup, Yangsan 50612, Korea. Tel: +82-55-360-1422, Fax: +82-55-360-2149, email@example.com
Received: September 18, 2018; Revised: December 5, 2018; Accepted: December 6, 2018
Going back to basics prior to mentioning the use of antipsychotics in patients with pain, the International Association for the Study of Pain (IASP) definition of pain can be summarized as an unpleasant experience, composed of sensory experience caused by actual tissue damage and/or emotional experience caused by potential tissue damage. Less used than antidepressants, antipsychotics have also been used for treating this unpleasant experience as adjuvant analgesics without sufficient evidence from research. Because recently developed atypical antipsychotics reduce the adverse reactions of extrapyramidal symptoms, such as acute dystonia, pseudo-parkinsonism, akathisia, and tardive dyskinesia caused by typical antipsychotics, they are expected to be used more frequently in various painful conditions, while increasing the risk of metabolic syndromes (weight gain, diabetes, and dyslipidemia). Various antipsychotics have different neurotransmitter receptor affinities for dopamine (D), 5-hydroxytryptamine (5-HT), adrenergic (α), histamine (H), and muscarinic (M) receptors. Atypical antipsychotics antagonize transient, weak D2 receptor bindings with strong binding to the 5-HT2A receptor, while typical antipsychotics block long-lasting, tight D2 receptor binding. On the contrary, antidepressants in the field of pain management also block the reuptake of similar receptors, mainly on the 5-HT and, next, on the norepinephrine, but rarely on the D receptors. Antipsychotics have been used for treating positive symptoms, such as delusion, hallucination, disorganized thought and behavior, perception disturbance, and inappropriate emotion, rather than the negative, cognitive, and affective symptoms of psychosis. Therefore, an antipsychotic may be prescribed in pain patients with positive symptoms of psychosis during or after controlling all sensory components.
Keywords: Antipsychotics, Dopamine, Drug related side effects and adverse reactions, D2 receptor antagonists, Extrapyramidal symptom, Histamine, Pain, Prolactin, Psychosis, Serotonin, Weight gain