Chronic Pain

Chronic pain is defined by the International Association for the Study of Pain (IASP) as persistent or recurrent pain lasting more than 3 months or beyond the normal tissue healing period 1. Chronic pain is a frequent health burden affecting approximately 20% of the adult population and includes cancer pain as well as chronic non-cancer pain 2,3.

The original WHO three-step analgesic ladder specifies treatment on pain intensity, from simple analgesics for mild pain to opioid analgesics for moderate and severe pain and is primarily designed for cancer pain management as a simple and valuable guideline 4. A four-step ladder including integrative therapies which can be adopted at each step for reducing or even stopping the use of opioid analgesics was recently developed for chronic non-cancer pain 5. If non-opioids and weak opioids failed, interventional therapies can be considered as step 3 before upgrading to strong opioids. Morphine sulphate is the archetypical opioid analgesic preferentially given as slow-release oral morphine (SROM) formulation when used in chronic pain 6.

    1. Merskey HE and Bogduk N. Classification of chronic pain: Descriptions of chronic pain syndromes and definitions of pain terms. Prepared by the International Association fort he Study of Pain, Subcommitee on Taxonomy. Pain Suppl.1986;3:S1-226.
    2. Breivik H, Collett B, Ventafridda V, Cohen R, Gallacher D. Survey of chronic pain in Europe: prevalence, impact on daily life, and treatment. Eur J Pain. 2006;10(4):287-333.
    3. Nahin RL, Feinberg T, Kapos FP, Terman GW. Estimated Rates of Incident and Persistent Chronic Pain Among US Adults, 2019-2020. JAMA Netw Open 2023;6(5):e2313563. doi:10.1001/jamanetworkopen.2023.13563
    4. Max M. World Health Organization cancer pain relief program: network news. J Pain Symptom Manage. 1986;1(1):53–57. 
    5. Yang J, Bauer BA, Wahner-Roedler DL, Chon TY, Xiao L. The Modified WHO Analgesic Ladder: Is It Appropriate for Chronic Non-Cancer Pain? J Pain Res. 2020;13:411-7.
    6. Balch RJ, Trescot A. Extended-release morphine sulfate in treatment of severe acute and chronic pain. J Pain Res. 2010;3:191-200.