Nonopioid and opioid analgesic pharmacotherapy of cancer pain

Side-effects of opioids in chronic pain treatment

The emergence of opioid-induced neurotoxicity has gained increasing recognition in the literature in the past decade. Exciting developments at the receptor and intracellular level have revealed some insights into the potential mechanisms underlying this phenomenon. The hitherto reported clinical benefits of opioid rotation and dose reduction in the treatment of opioid toxicity warrant further clarification in prospective studies, particularly in relation to their relative value.

Ensuring pain relief for children at the end of life

Pain management in the context of pediatric palliative care can be challenging. The present article reviews, through a case-based presentation, the nonpharmacological and pharmacological methods used to ensure adequate pain control in children facing end of life. Details on the impressive range of opioid dosages required and routes of administration are highlighted from published literature and clinical experience. Where available, evidence-based recommendations are provided. Potential side effects of pain medication and barriers to good pain control are discussed. Novel analgesics and innovative delivery methods are presented as future tools enhancing pain relief at the end of life. Some challenges to ethically grounded research in this important context of care are reviewed.

Pain in children who have life-limiting conditions

Children and adolescents who have life-limiting conditions are vulnerableto acute and chronic pain problems. Many compounding and complicatingfactors often need to be explored in this setting. Barriers to effective painmanagement include poor assessment and measurement of pain anda lack of specialist knowledge. Fears regarding the use of opioids and theirassociation with the end of life must be addressed openly and with clarity.Day-to-day management should include continual appraisal of pain issuesif quality of life is to be maximized. Pain is a complicated phenomenon. The impact of pain and the compli-cated dynamic of suffering in children and young people who have life-lim-iting conditions must not be underestimated. The clinician must be vigilantand take responsibility for all aspects of pain management in these patients.

Chronic neuropathic pain. Mechanisms, diagnosis, and treatment

BACKGROUND

The management of chronic pain represents a significant public health issue in the United States. It is both costly to our health care system and devastating to the patient's quality of life. The need to improve pain outcomes is reflected by the congressional declaration of the present decade as the "Decade of Pain Control and Research," and the acknowledgment in January 2001 of pain as the "fifth vital sign" by the Joint Commission of Healthcare Organizations.

REVIEW SUMMARY

At present, therapeutic options are largely limited to drugs approved for other conditions, including anticonvulsants, antidepressants, antiarrhythmics, and opioids. However, treatment based on the underlying disease state (eg, postherpetic neuralgia, diabetic neuropathy) may be less than optimal, in that 2 patients with the same neuropathic pain syndrome may have different symptomatology and thus respond differently to the same treatment. Increases in our understanding of the function of the neurologic system over the last few years have led to new insights into the mechanisms underlying pain symptoms, especially chronic and neuropathic pain.

CONCLUSIONS

The rapidly evolving symptom- and mechanism-based approach to the treatment of neuropathic pain holds promise for improving the quality of life of our patients with neuropathic pain.

Radiotherapy plus either transdermal fentanyl or paracetamol and codeine for painful bone metastases: a randomised study of pain relief and quality of life

OBJECTIVE

To compare the effects of providing analgesia with either transdermal fentanyl (TTS-fentanyl) or paracetamol and codeine (P/C) in addition to radiotherapy in patients with metastatic bone pain.

METHODS

In a prospective study, 26 patients with radiologically confirmed bony metastases received radiotherapy (R/T). They were randomised to receive either 500 mg paracetamol and 30 mg codeine four times per day (P/C group), or transdermal fentanyl patches delivering 25 microg fentanyl/h (TTS-fentanyl group). Pain was assessed using visual analogue pain ratings (VAS) and the Greek Brief Pain Inventory (G-BPI) questionnaire administered before R/T and after 3 months.

RESULTS

Data were available from 24 eligible patients. Use of TTS-fentanyl was associated with significantly superior pain relief. Mean VAS fell from 7.0 to 1.1 with TTS-fentanyl and from 8.3 to 4.3 with P/C, p< 0.01. The TTS-fentanyl group also showed significantly greater improvements of important G-BPI domains including global quality of life, pain, and physical, cognitive, and role functioning, than the P/C group (p< 0.01). Four patients receiving TTS-fentanyl and three receiving P/C reported severe nausea/vomiting.

CONCLUSIONS

Transdermal fentanyl combined with R/T was more effective in reducing metastatic bone pain and resulted in greater improvements in quality of life than paracetamol and codeine.

Pain management in the hospitalized patient

Pain is unnecessary. Effective tools are available to help doctors evaluate pain in their patients. Unrelieved pain should be treated just like any other vital sign: with aggressive measures. Effective therapies are available to treat pain. Use guidelines to develop a rational plan to relieve pain. Side effects are manageable. Anticipate side effects and treat aggressively. Addiction rarely occurs. Trust your patient when they report pain. Tolerance and physical dependence can occur. Plan and you will succeed. Take the initiative and focus on relieving pain at your hospital. Your patients depend on it.

Palliative care and the child with cancer

There is a growing awareness and a WHO directive that the palliative care paradigm should be incorporated into the care of all children with cancer, irrespective of geographic location. The barriers to pediatric palliative care identified by pediatric oncologists [3] are lack of formal courses in pediatric palliative care, a high reliance on trial-and-error learning, lack of strong role models, and lack of access to a pain and palliative care service. These barriers must be overcome.

The panorama of opioid-related cognitive dysfunction in patients with cancer: a critical literature appraisal

BACKGROUND

Opioids have an essential role in the management of pain in cancer patients, particularly those with advanced disease. Cognitive dysfunction is a recognized complication of opioid use. However, misconceptions and controversy surround the nature and prevalence of its occurrence. A projected increase in the aging cancer population highlights the need for a better understanding of this phenomenon.

METHODS

A critical appraisal of the literature evidence in relation to the pattern, pathophysiology, assessment, impact, and management of cognitive dysfunction due to opioid use in cancer pain management is given.

RESULTS

Studies in cancer patients with less advanced disease reveal subtle evidence of cognitive impairment, largely related to initial dosing or dose increases. In advanced cancer, opioid-induced cognitive dysfunction usually occurs in the form of delirium, a multifactorial syndrome. The presence of both cognitive impairment and delirium frequently is misdiagnosed or missed. Potential risk factors include neuropathic and incidental pain, opioid tolerance, somatization of psychologic distress, and a history of drug or alcohol abuse. Elevation of opioid metabolites with renal impairment may contribute to cognitive dysfunction. Recognition of opioid-related cognitive dysfunction is improved by objective screening. Successful management requires either dose reduction or a change of opioid, in addition to addressing other reversible precipitants such as dehydration or volume depletion.

CONCLUSIONS

Opioid-related cognitive dysfunction tends to be subtle in the earlier stages of cancer, whereas delirium, a more florid form with behavioral disturbance is likely to be present in the advanced cancer population. In patients with advanced disease, an optimal management approach requires careful clinical assessment, identification of risk factors, objective monitoring of cognition, maintenance of adequate hydration, and either dose reduction or switching to a different opioid.

The management of pain in the oncology patient

The treatment of cancer pain is improving, but pain remains a significant problem. Although better analgesics with greater efficacy and fewer side effects are needed, the most significant problem regarding the appropriate management of cancer pain remains a lack of knowledge among physicians treating cancer patients. Cancer management should be undertaken within a palliative care model, in which autonomy and respect for individuals and their families guides all aspects of care.

Opioid and Nonopioid Therapy in Cancer Pain: The Traditional and the New

Management of cancer pain has made sidnificant progress in recent years, partly due to the Agency for Health Care Policy and Research (AHCPR) guidelines, but mostly it seems to be due to the death and dying movement in the world. However, cancer pain on occasion poses significant problems and needs accurate diganosis and appropriate intervention. Pharmacotherapy remains the mainstay of treating cancer pain. Most cancer pain syndromes present with moderate to severe pain, associated with several comorbid problems necessitating the multidisciplinary approach to optimally treat it. The psychologic factors associated wth serious illness, terminal prognoses, and dying complicate the scenario even more as compared with that of nonmalignant pain. Although such patients are entitled to more aggressive analgesic therapy, it is unfortunate that this is not achieved in a significant percentage of cases. In this review, we address some of the above issues and attempt to summarize the traditional pharmacologic therapies highlighting their modern modes of implementation in cancer pain management. Special emphasis on the state-of-the art innovations in this field wil be noted.

Differences in the ratios of morphine to methadone in patients with neuropathic pain versus non-neuropathic pain

The use of methadone in the treatment of cancer pain is becoming more attractive mainly because of its known efficacy, lack of active metabolites, and low cost. Methadone also blocks the n-methyl-D-aspartate (NMDA) receptor, and this property may result in other clinical advantages. Because of this capacity of methadone to block the NMDA receptors, we have hypothesized that the equianalgesic dose ratio of hydromorphone or morphine to methadone will be different in patients with neuropathic pain than in patients with non-neuropathic pain. To explore this hypothesis, we reviewed computerized patient records and determined the ratio of morphine and hydromorphone (expressed as morphine subcutaneous equivalent dose) to methadone in patients who underwent rotation from morphine or hydromorphone to methadone. We found that the ratio of morphine subcutaneous equivalent dose to methadone is between 5 and 7, which is different from previously described dose ratios. However, our study failed to show a difference in the ratios of patients with neuropathic or non-neuropathic pain syndromes.