Adjuvant Agents in Cancer Pain

Abstract

Cancer-related neuropathic pain derives from peripheral or central lesions of the nervous system and is often associated with the hallmark symptoms of allodynia (pain from a stimulus that does not normally evoke pain) and hyperalgesia (an exaggerated pain response to a normally painful stimulus). Pain is prevalent in patients with cancer and considerably undermines their quality of life, thereby making the development of a comprehensive pain management approach essential. Coanalgesics have been well integrated into cancer pain management strategies and are often used as first-line options for treatment of certain disease processes such as neuropathic pain. These medicines, including antidepressant and anticonvulsant agents, are recommended by evidence-based guidelines, whereas others, such as lidocaine patch 5%, are supported by randomized, controlled, clinical trial data. In addition to understanding which agents are recommended for neuropathic pain, it is useful to know which agents are of limited utility or are to be avoided when prescribing treatment for neuropathic pain. Notwithstanding the need for head-to-head studies before firm statements on comparative efficacy can be made, it is worth considering the numbers needed to treat statistic for the treatment of neuropathic pain with coanalgesics. Potentially harmful treatments are considered, as well as the numbers needed to treat, mechanisms of action, and clinical trial data for agents that can be beneficial for the management of cancer-associated neuropathic pain.

Pharmacological Treatment of Neuropathic Cancer Pain: A Comprehensive Review of the Current Literature

“…However, antidepressants and anticonvulsants are recommended by evidence-based guidelines in NCP therapy. 119 Adjuvants can be added at any stage of the WHO ladder and are selected following underlying pain pathophysiology, although it is common to be generally prescribed early during NCP treatment. 111 At present, a number of approaches target at reducing levels of cancer-related pain.…”

Emerging drugs for cancer-related pain

“…In cancer pain, cannabinoids have demonstrated efficacy comparable to some specific opioids like codeine [23]. There is evidence of synergy between cannabinoids and morphine, cannabinoids modulating endogenous opioid tone.…”

“…Alternately, duloxetine is often used because of its efficacy comparable to tricyclics without the concomitant adverseeffects burden, as it is less sedative. However, studies of antidepressant agents for treatment of cancer pain are few in number [23].…”

“…The widely used adjuvant analgesics are an important part of the neuropathic pain armamentarium [23]; the choice of adjuvant analgesic is not based on potency superiority as all have a number needed to treat of about three [3].…”

Effective pain management in hematological malignancies

“…Effective pain management in hematological malignancies benzodi azepines and biphosphonates, pharmacologically unrelated to analgesics, are able to indirectly contribute to alleviate the pain and can be of crucial value in relieving some pain syndromes that are difficult to treat, such as those of neuropathic origin [20].…”