HOME

Review Article

Korean J Pain 2020; 33(2): 108-120

Published online April 1, 2020 https://doi.org/10.3344/kjp.2020.33.2.108

Copyright © The Korean Pain Society.

All about pain pharmacology: what pain physicians should know

Kyung-Hoon Kim1 , Hyo-Jung Seo1 , Salahadin Abdi2 , Billy Huh2

1Department of Anesthesia and Pain Medicine, School of Medicine, Pusan National University, Yangsan, Korea
2Department of Pain Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA

Correspondence to:Kyung-Hoon Kim
Department of Anesthesia and Pain Medicine, Pusan National University Yangsan Hospital, 20 Geumo-ro, Mulgeum-eup, Yangsan 50612, Korea
Tel: +82-55-360-1422
Fax: +82-55-360-2149
E-mail: pain@pusan.ac.kr

Received: February 8, 2020; Revised: March 12, 2020; Accepted: March 13, 2020

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

From the perspective of the definition of pain, pain can be divided into emotional and sensory components, which originate from potential and actual tissue damage, respectively. The pharmacologic treatment of the emotional pain component includes antianxiety drugs, antidepressants, and antipsychotics. The anti-anxiety drugs have anti-anxious, sedative, and somnolent effects. The antipsychotics are effective in patients with positive symptoms of psychosis. On the other hand, the sensory pain component can be divided into nociceptive and neuropathic pain. Non-steroidal anti-inflammatory drugs (NSAIDs) and opioids are usually applied for somatic and visceral nociceptive pain, respectively; anticonvulsants and antidepressants are administered for the treatment of neuropathic pain with positive and negative symptoms, respectively. The NSAIDs, which inhibit the cyclo-oxygenase pathway, exhibit anti-inflammatory, antipyretic, and analgesic effects; however, they have a therapeutic ceiling. The adverse reactions (ADRs) of the NSAIDs include gastrointestinal problems, generalized edema, and increased bleeding tendency. The opioids, which bind to the opioid receptors, present an analgesic effect only, without anti-inflammatory, antipyretic, or ceiling effects. The ADRs of the opioids start from itching and nausea/vomiting to cardiovascular and respiratory depression, as well as constipation. The anticonvulsants include carbamazepine, related to sodium channel blockade, and gabapentin and pregabalin, related to calcium blockade. The antidepressants show their analgesic actions mainly through inhibiting the reuptake of serotonin or norepinephrine. Most drugs, except NSAIDs, need an updose titration period. The principle of polypharmacy for analgesia in case of mixed components of pain is increasing therapeutic effects while reducing ADRs, based on the origin of the pain.

Keywords: Analgesics, Anticonvulsants, Antidepressive Agents, Anti-Inflammatory Agents, Non-Steroidal, Carbamazepine, Gabapentin, Neuralgia, Nociceptive Pain, Opioids, Polypharmacy, Pregabalin, Serotonin.