%0 Journal Article
%T Pain Management in the Era of the Opioid Crisis
%A Eduardo Bruera
%A Egidio Del Fabbro
%J About the Ed Book | ASCO Educational Book
%D 2018
%R https://doi.org/10.1200/EDBK_208563
%X The vast majority of patients diagnosed with cancer will have episodes of acute or chronic pain.1,2 Not all those episodes require opioid management. However, opioids will be necessary in almost all patients at some point for the management of acute or chronic pain. Table 1 summarizes common pain syndromes among patients with cancer that frequently or rarely require systemic opioid treatment. TABLE 1. Pain Syndromes in Patients With Cancer TABLE 1.Pain Syndromes in Patients With Cancer View larger version (105K) Opioids are highly effective analgesics, and all physicians involved in the treatment of cancer patients should be familiar with the most common types and dosages of opioid analgesics as well as the management of their most common side effects.3 Figure 1 summarizes the complex effects of opioids on different central nervous system regions. Systemic opioids bind to mu receptors along the nociceptive pathway and reduce neuronal activity and pain perception at the somatosensory cortex. Unfortunately, opioids also bind to mu receptors anywhere in the body where they are available. As a result, patients experience mu-related side effects such as constipation and somnolence. Mu receptors are located also along the limbic system, and they are therefore able to produce considerable reward, especially in patients with large concentrations of mu receptors in those regions. There is a slow development of tolerance and hyperalgesia along the nociceptive pathway and a much faster reduction of the reward effect centrally. This rapid loss of the reward effect is associated with the increased activity of dysphoric pathways that are not mu related. Patients who are at higher risk for the development of substance use disorders will increase opioid intake in an effort to restore the reward, followed by once again rapid loss of such effect. FIGURE 1. Opioid Effects on the Nociceptive and Non-Nociceptive Pathways Abbreviation: MOR, mu opioid receptor. Approximately 80% of patients receiving opioids for the management of cancer pain will adhere to the opioids as prescribed and will have no major difficulties with dose reduction and even discontinuation if the pain syndrome resolves.4 The remaining 20% are at risk for behaviors consistent with the nonmedical use of the opioid analgesic (also defined as aberrant behaviors) or will ultimately develop substance use disorders. There are risk factors associated with the development of opioid dependence among patients with advanced cancer. Among these, the most common risk factor is a history of alcoholism. Positive
%U http://ascopubs.org/doi/full/10.1200/EDBK_208563