A long-term survey of morphine in cancer pain patients

Survey of Opioid Risk Tool Among Cancer Patients Receiving Opioid Analgesics

BACKGROUND

The risk of opioid-related aberrant behavior (OAB) in Korean cancer patients has not been previously evaluated. The purpose of this study is to investigate the Opioid Risk Tool (ORT) in Korean cancer patients receiving opioid treatment.

METHODS

Data were obtained from a multicenter, cross-sectional, nationwide observational study regarding breakthrough cancer pain. The study was conducted in 33 South Korean institutions from March 2016 to December 2017. Patients were eligible if they had cancer-related pain within the past 7 days, which was treated with strong opioids in the previous 7 days.

RESULTS

We analyzed ORT results of 946 patients. Only one patient in each sex (0.2%) was classified as high risk for OAB. Moderate risk was observed in 18 males (3.3%) and in three females (0.7%). Scores above 0 were primarily derived from positive responses for personal or familial history of alcohol abuse (in men), or depression (in women). In patients with an ORT score of 1 or higher (n = 132, 14%), the score primarily represented positive responses for personal history of depression (in females), personal or family history of alcohol abuse (in males), or 16-45 years age range. These patients had more severe worst and average pain intensity (proportion of numeric rating scale ≥ 4: 20.5% vs. 11.4%, P < 0.001) and used rescue analgesics more frequently than patients with ORT scores of 0. The proportion of moderate- or high-risk patients according to ORT was lower in patients receiving low doses of long-acting opioids than in those receiving high doses (2.0% vs. 6.6%, P = 0.031). Moderate or high risk was more frequent when ORT was completed in an isolated room than in an open, busy place (2.7% vs. 0.6%, P = 0.089).

CONCLUSIONS

The score of ORT was very low in cancer patients receiving strong opioids for analgesia. Higher pain intensity may associate with positive response to one or more ORT item.

Supraglottic Carcinoma in Intravenous Opioid Drug Abusers: A Distinct Disease with Improved Survival

OBJECTIVES/HYPOTHESIS

Recent evidence indicates an increased prevalence of intravenous opioid drug abusers (IVDAs) among supraglottic squamous cell carcinoma (SG-SCC) patients. This study investigates whether the clinical course of SG-SCC in IVDA differs from SG-SCC in non-IVDA.

STUDY DESIGN

A retrospective case-control study conducted in a in two tertiary referral centers.

METHODS

This case-control study compares IVDA with non-IVDA patients diagnosed and treated for SG-SCC in between 2005 and 2018. Disease-free survival (DFS) and overall survival (OS) were calculated using the Kaplan-Meier estimator. Adjusted odds ratios (ORs) for mortality were calculated using multivariant analyses.

RESULTS

A total of 124 patients were included; 21% (26) were IVDA, and 79% (98) were non-IVDA. Age at diagnosis in the IVDA group versus the non-IVDA group was 53 and 66 years, respectively (P = .001). Nevertheless, the age hazard ratio for OS was calculated and found to have minimal to no effect, 1.05 (95% Cl: 1.025-1.076). Otherwise, the two groups were comparable regarding demographics, other risk factors (i.e., gender, smoking, and alcohol), and comorbidities status, as well as the comparable stage at diagnosis, histologic grading, and treatment modalities. Although the DFS was comparable in both groups, the 5-year OS was 55% in the IVDA group compared with 34% among the non-IVDA patients (P = .04). In multivariant analyses for mortality, positive IVDA history was found to be protective, adjusted OR: 0.263 (95% CI: 0.081-0.854). Similarly, within the subgroup of 100 patients with advanced-stage disease (III and IV), the adjusted OR was 0.118 (95% CI: 0.028-0.495).

CONCLUSIONS

SG-SCC in IVDA patients has a distinct clinical course, presenting at a younger age, and may have improved prognosis.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:E1190-E1197, 2021.

Craving Behavior from Opioid Addiction Controlled with Olanzapine in an Advanced Cancer Patient: A Case Report

Opioid addiction, although uncommon in cancer patients, can be a significant challenge for optimal pain management in certain patients. We present a case of a 59-year-old man with advanced colon cancer whose compulsive craving for the buccal tablet of fentanyl citrate (BTFC) was improved with the use of olanzapine. He was hospitalized for abdominal pain caused by disease progression. He had visited several times at outpatient follow-up to obtain a prescription for BTFC because he took all medications before the appointed times. After admission, intravenous infusion of oxycodone and opioid rotation were applied to the patient to control his pain. However, he complained that the pain was not relieved at all and persistently asked for only BTFC 7 to 15 times per day. With the diagnosis of opioid addiction, the transdermal buprenorphine patch was applied, but was ineffective for controlling the addictive behaviors. Finally, olanzapine (10 mg/day per os), a dopamine receptor antagonist, was given to control the craving behavior because psychological dependence is mediated by the dopaminergic system. Three days later, opioid craving was reduced from five to one on a 5-point Likert scale. The pain was well controlled to numeric rating scale 1 or 2 without cravings for BTFC. Craving behavior as a result of opioid addiction may be controlled with olanzapine. Further prospective studies on this issue are warranted.

Breakthrough cancer pain (BTcP) management: a review of international and national guidelines

OBJECTIVE

Breakthrough cancer pain (BTcP) is common and has a significant impact on the quality of life of patients with cancer. This review compares current national/international BTcP guidelines in order to identify disparities and priorities for further research.

METHODS

Relevant guidelines were identified using searches of PubMed, the National Guideline Clearinghouse, the internet (commercial search engines), and correspondence with key opinion leaders and relevant pharmaceutical companies. Identified guidelines were compared, using the Association for Palliative Medicine of Great Britain and Ireland recommendations as the 'reference' guideline.

RESULTS

Ten specific BTcP guidelines were identified/reviewed, as well as major international generic cancer pain guidelines. In general, there was good agreement between the specific BTcP guidelines, although there remain some differences in terms of definition, diagnostic criteria and treatment of BTcP. Disparities between the different BTcP guidelines invariably reflect personal opinion rather than research evidence. Generic cancer pain guidelines continue to support the use of oral opioids as rescue medication, while specific BTcP guidelines invariably endorse the use of transmucosal opioids as rescue medication.

CONCLUSION

Current guidelines agree on many aspects of the management of BTcP. However, the evidence to support current guidelines remains low grade, and so more research is needed in this area of care. Moreover, there needs to be an international consensus on the definition and diagnosis criteria of BTcP.

Brain Reward Circuits in Morphine Addiction

Morphine is the most potent analgesic for chronic pain, but its clinical use has been limited by the opiate's innate tendency to produce tolerance, severe withdrawal symptoms and rewarding properties with a high risk of relapse. To understand the addictive properties of morphine, past studies have focused on relevant molecular and cellular changes in the brain, highlighting the functional roles of reward-related brain regions. Given the accumulated findings, a recent, emerging trend in morphine research is that of examining the dynamics of neuronal interactions in brain reward circuits under the influence of morphine action. In this review, we highlight recent findings on the roles of several reward circuits involved in morphine addiction based on pharmacological, molecular and physiological evidences.

Effectiveness of the World Health Organization cancer pain relief guidelines: an integrative review

Inadequate cancer pain relief has been documented extensively across historical records. In response, in 1986, the World Health Organization (WHO) developed guidelines for cancer pain treatment. The purpose of this paper is to disseminate the results of a comprehensive, integrative review of studies that evaluate the effectiveness of the WHO guidelines. Studies were included if they: 1) identified patients treated with the guidelines, 2) evaluated self-reported pain, 3) identified instruments used, 4) provided data documenting pain relief, and 5) were written in English. Studies were coded for duration of treatment, definition of pain relief, instruments used, findings related to pain intensity or relief, and whether measures were used other than the WHO analgesic ladder. Twenty-five studies published since 1987 met the inclusion criteria. Evidence indicates 20%-100% of patients with cancer pain can be provided pain relief with the use of the WHO guidelines - while considering their status of treatment or end-of-life care. Due to multiple limitations in included studies, analysis was limited to descriptions. Future research to examine the effectiveness of the WHO guidelines needs to consider recommendations to facilitate study comparisons by standardizing outcome measures. Recent studies have reported that patients with cancer experience pain at moderate or greater levels. The WHO guidelines reflect the knowledge and effectual methods to relieve most cancer pain, but the guidelines are not being adequately employed. Part of the explanation for the lack of adoption of the WHO guidelines is that they may be considered outdated by many because they are not specific to the pharmacological and interventional options used in contemporary pain management practices. The conundrum of updating the WHO guidelines is to encompass the latest pharmacological and interventional innovations while maintaining its original simplicity.

Management of opioid-induced constipation for people in palliative care

Constipation is common in the palliative population. Opioid medications, which are frequently prescribed to this cohort, represent a significant risk factor for this condition. Opioid-induced constipation may be of such severity that opioid doses are reduced or missed, and analgesia and quality of life are therefore reduced. However, underlying chronic constipation, local and systemic disease effects, and other medications may also precipitate constipation in this population. The assessment and treatment of constipation in a palliative individual should be undertaken in a fashion similar to that used in non-palliative patients. Initial management should include minimising exposure to predisposing factors and general measures such as encouraging hydration, fibre intake and mobility. Pharmacological treatment should commence with a stool softener and a stimulant laxative. Recently published literature demonstrates that newer laxatives, including lubiprostone (a chloride channel activator) and prucalopride (a 5-HT4 receptor agonist) can effectively treat opioid-induced constipation. For patients not responding to laxatives, opioid antagonists (non-specific or peripherally acting μ-opioid receptor antagonists) can be co-prescribed with laxatives. These agents have also proven efficacy in treating opioid-induced constipation. This review discusses the recent literature regarding the management of opioid-induced constipation and provides a rational approach to assessing and managing constipation in the palliative population.

The mu opioid receptor: A new target for cancer therapy?

Mu opioids are among the most widely used drugs for patients with cancer with both acute and chronic pain as well as in the perioperative period. Several retrospective studies have suggested that opioid use might promote tumor progression and as a result negatively impact survival in patients with advanced cancer; however, in the absence of appropriate prospective validation, any changes in recommendations for opioid use are not warranted. In this review, the authors present preclinical and clinical data that support their hypothesis that the mu opioid receptor is a potential target for cancer therapy because of its plausible role in tumor progression. The authors also propose the hypothesis that peripheral opioid antagonists such as methylnaltrexone, which reverses the peripheral effects of mu opioids but maintains centrally mediated analgesia and is approved by the US Food and Drug Administration for the treatment of opioid-induced constipation, can be used to target the mu opioid receptor.

Long-Term High-dose Oral Morphine in Phantom Limb Pain with No Addiction Risk

Chronic phantom limb pain (PLP) is a type of neuropathic pain, which is located in the missing/amputated limb. Phantom pain is difficult to treat as the exact basis of pain mechanism is still unknown. Various methods of treatment for PLP have been described, including pharmacological (NSAIDs, opioids, antiepileptic, antidepressants) and non-pharmacological (TENS, sympathectomy, deep brain stimulation and motor cortex stimulation). Opioids are used for the treatment of neuropathic pain and dose of opioid is determined based on its effect and thus there is no defined ceiling dose for opioids. We report a case where a patient receiving high-dose oral morphine for chronic cancer pain did not demonstrate signs of addiction.

[Cancer pain management]

Pain is a significant and alarming symptom of cancer seriously affecting the activity and quality of life of patients. Recent research proved that inadequate analgesia shortens life expectancy. Therefore, pain relief is not only a possibility but a professional, ethical and moral commitment to relieve patients from suffering, as well as ensure their adequate quality of life and human dignity. Proper pain relief can be achieved with medical therapy in most of the cases and the pharmacological alternatives are available in Hungary. Yet medical activity regarding pain relief is far from the desired. This paper gives a short summary of the guidelines on medical pain management focusing particularly on the use of opioids.

Effects of methylnaltrexone on guinea pig gastrointestinal motility

The purpose of the present study was to compare the effects of methylnaltrexone (MNTX), a peripherally acting μ opioid receptor (μOR) antagonist, on gastrointestinal (GI) motility in naïve vs. opiate chronically treated guinea pigs in vitro and in vivo. We have used the electrically stimulated muscle twitch contractions of longitudinal muscle-myenteric plexus (LMMP) preparations and total GI transit as measure of GI motility. In LMMP preparations of naïve guinea pigs, MNTX (1-30 μM) induced a significant, dose-response reduction of morphine-induced inhibition of electrically stimulated muscle twitch contractions, with an IC50 of 9.4 10(-8)M. By contrast, MNTX abolished the inhibitory effect of acute morphine at any concentrations tested (1-30 μM) in the guinea pigs chronically treated with opiates. In vivo, MNTX (10-50 mg s.c.) did not affect GI transit in naïve guinea pigs when administered acutely or for five consecutive days, but reversed the GI transit delay induced by chronic morphine treatment. These findings show that MNTX is effective in reversing opiate-induced inhibition of GI motility acting at peripheral μ opioid receptors, but does not exert a pharmacologic effect on GI transit in the absence of opiate stimulation.

A multi-institutional study analyzing effect of prophylactic medication for prevention of opioid-induced gastrointestinal dysfunction

OBJECTIVES

The aim of this study was to evaluate the effectiveness of prophylactic treatment with laxatives and antiemetics on the incidence of gastrointestinal adverse reactions such as constipation, nausea and vomiting in cancer patients who received oral opioid analgesics for the first time.

METHODS

A multi-institutional retrospective study was carried out, in which 619 eligible hospitalized patients receiving oral opioid analgesics for cancer pain were enrolled from 35 medical institutions. The primary endpoint was the incidence of opioid-induced side effects in patients receiving prophylactic medication. Odds ratios of the incidence of adverse reactions in the absence or presence of premedication obtained from several institutions were subjected to a meta-analysis.

RESULTS

Among 619 patients, the incidence of constipation was significantly lower in patients receiving laxatives, including magnesium oxide, as premedication than in those without them (34% vs. 55%, odds ratio=0.432, 95% confidence interval=0.300-0.622, P<0.001). However, the incidence of nausea or vomiting was similar regardless of prophylactic medication with dopamine D2 blockers. The results of the meta-analysis revealed that prophylactic laxatives significantly reduced the incidence of constipation (overall odds ratio=0.469, 95% confidence interval=0.231-0.955, P=0.037), whereas dopamine D2 blockers were not effective in preventing opioid-induced nausea or vomiting.

DISCUSSION

We showed evidence for the effectiveness of premedication with laxatives for prevention of opioid-induced constipation. However, premedication with dopamine D2 blockers was not sufficient to prevent nausea or vomiting.

Laxative prescriptions to cancer outpatients receiving opioids: a study from the Norwegian prescription database

BACKGROUND

During opioid treatment of cancer pain, constipation is one of the most prevalent and bothersome side effects. Guidelines suggest that treatment with laxatives should be initiated when opioid therapy is started.

AIM

This study aims: (1) to determine to what extent patients, starting on opioids due to cancer pain, receive laxatives; (2) to examine the temporal relationship between initiation of opioid therapy and initiation of treatment with laxatives; and (3) to study to which extent the treatment follows current guidelines.

METHODS

Data from the Norwegian prescription database (NorPD) were used to investigate dispensed prescriptions of laxatives to outpatients in Norway, who are receiving opioids for cancer pain. Data from NorPD cover all dispensed prescriptions of drugs to outpatients, making it possible to follow patients over time. The study cohort was followed from 2005 to the end of 2008.

RESULTS

Of 2,982 patients who started opioid therapy directly with WHO step III opioids, 1,325 patients (44.4 %) did not receive laxatives during the study period. Only 738 patients (24.7 %) received laxatives at the same time as opioid therapy was initiated. Another 657 patients (22.0 %) received laxatives after their initiation of opioids at some time during the study period.

CONCLUSION

Of those who started directly on a strong opioid, only one fourth received laxatives concomitantly with the first opioid, and nearly half did not receive laxatives at all. These findings indicate that the current guidelines are not followed.

Methylnaltrexone: treatment for opioid-induced constipation

Opioids have become the gold standard for treatment of severe pain in advanced disease, but adverse effects can affect the quality of life. Opioid-induced bowel dysfunction can lead to refractory constipation. Methylnaltrexone bromide is a peripherally acting mu antagonist and is indicated for the treatment of opioid-induced constipation in patients with advanced illness, when response to standard laxative therapy has been inefficacious. This pharmacology update will review the etiology, pathophysiology, and treatment of opioid-induced constipation, focused on methylnaltrexone as a novel treatment for refractory cases.

Negligible analgesic tolerance seen with extended release oxymorphone: a post hoc analysis of open-label longitudinal data

OBJECTIVE

To examine the development of analgesic tolerance in patients on oxymorphone extended-release (OxymER).

DESIGN

Post hoc analysis of data from a previously conducted prospective 1 year multi-center open-label extension study in which patients were able to titrate as needed.

PATIENTS

Sample of 153 hip and knee osteoarthritis (OA) subjects on OxymER. Primary analyses were limited to study completers (n = 62) due to the large amount of missing data for the noncompleters (n = 91).

OUTCOME MEASURES

Main outcome measures included OxymER doses (pill counts) and pain intensity ratings using a visual analog scale at monthly visits.

RESULTS

There were significant dose increases from weeks 1 to 2 and 2 to 6 (P < 0.05). Doses stabilized around week 6, suggesting the completion of what we defined as "titration." Both doses and pain ratings were stable when this titration phase was excluded from the analysis (P = 0.751; P = 0.056, respectively). Only 28% of the patients had any dose changes following this titration. While there was a significantly greater dose at week 52 compared with week 10 (P = 0.010), the increase in dose became insignificant after excluding four subjects who required two dose increases (P = 0.103).

CONCLUSIONS

The results showed that most of the titration/dose stabilization changes occurred within the first 10 weeks. A minority (28%) of subjects required dosage increases after this (defined) titration period. Pain reports stabilized statistically after 2 weeks. The findings of this post hoc analysis suggest a lack of opioid tolerance in the majority (72%) of these OA patients who completed this study following a defined titration period on OxymER.

SUMMARY

This post hoc analysis of oxymorphone ER consumption in osteoarthritis pain vs pain report showed that most dose changes occurred during an initial "titration period" as defined. Following this titration few subjects increased dose and analgesia remained stable. These findings suggest a lack of longitudinal opioid tolerance in the majority of those OA subjects who completed the trial.

Methylnaltrexone: the evidence for its use in the management of opioid-induced constipation

Introduction:

Constipation is a distressing side effect of opioid treatment, being so irksome in some cases that patients would rather suffer the pain than the side effect of opioid analgesics. Stool softeners or stimulating laxatives are often ineffective or even aggravate the situation. A new efficacious and safe drug is needed to limit the frequently observed side effects induced by effective opioid-based analgesic therapy and to improve the quality of life for patients, most of whom are impaired by a severe disease.

Aims:

The purpose of this article is to assess current evidence supporting the use of the peripherally acting μ-opioid receptor antagonist, methylnaltrexone, to restrict passage across the blood–brain barrier in patients with opioid-induced bowel dysfunction.

Evidence review:

There are now convincing data from phase II and multicenter phase III randomized, double-blind, placebo-controlled trials that methylnaltrexone induces laxation in patients with long-term opioid use without affecting central analgesia or precipitation of opioid withdrawal. Onset of the effect is rapid and improvement is maintained for at least 3 months during the drug treatment. The action of methylnaltrexone is dose dependent. Weight-related dosing appeared to be effective. There were no severe side effects or signs of opioid withdrawal. Adverse events, most frequently abdominal cramping or nausea, were usually mild to moderate. Methylnaltrexone is contraindicated in patients with known or suspected mechanical intestinal stenosis. Patients receiving methylnaltrexone must be monitored.

Place in therapy:

Methylnaltrexone applied subcutaneously every other day may be given to patients suffering from chronic constipation due to opioid therapy for whom laxatives do not provide adequate relief of their symptoms.

Opioids for palliation of refractory dyspnea in chronic obstructive pulmonary disease patients

PURPOSE OF REVIEW

Dyspnea, a distressing symptom, in chronic obstructive pulmonary disease patients is often unrelieved. The purpose of this article is to examine the efficacy of opioids administered orally, in nebulized form and other routes in dyspnea relief. Additionally, factors that inhibit the prescription of opioids and use of opioids are explored.

RECENT FINDINGS

Although there are multiple case reports and case series, there is a paucity of well designed, prospective, randomized controlled trials with large enough number of chronic obstructive pulmonary disease patients. One review of randomized controlled trials and another randomized controlled trial found opioids effective in relieving dyspnea without causing major adverse effects.

SUMMARY

Opioid is an effective palliative drug in chronic obstructive pulmonary disease patients with distressing dypnea that is refractory to standard modalities of treatment.

Methylnaltrexone: the answer to opioid-induced constipation?

Opioid-induced constipation is a significant problem particularly for end stage cancer patients, methadone users, patients suffering from chronic pain as well as surgical patients. Until recently, there were few efficacious treatment options that did not have significant side effects. Methylnaltrexone is a promising drug for the treatment of opioid-induced constipation. It is an opioid-receptor antagonist that blocks the peripheral gastrointestinal opioid receptors responsible for opioid-induced bowel dysfunction. Due to the drug's polarity, it does not cross the blood-brain barrier; therefore, it does not block the central opioid receptors, thus, retaining effective analgesia. Methylnaltrexone has been recently approved by the FDA in the subcutaneous form for the treatment of opioid-induced bowel dysfunction, whereas the intravenous and oral forms remain under investigation.

Novel opioid antagonists for opioid-induced bowel dysfunction and postoperative ileus

Peripherally acting mu-opioid receptor antagonists methylnaltrexone and alvimopan are a new class of drugs designed to reverse opioid-induced side-effects on the gastrointestinal system without compromising pain relief. This article gives an overview of the pharmacology, the efficacy, and adverse effects of these drugs. Both compounds seem to be generally well tolerated and effective for the treatment of opioid-related bowel dysfunction and postoperative ileus. Methylnaltrexone recently received approval by the US Food and Drug Administration (FDA) and the European Medicines Agency for treatment of opioid-related bowel dysfunction in patients with advanced illness. Alvimopan was recently approved by the FDA for treatment of postoperative ileus, but the use of the drug is restricted to inpatients because it has been associated with an increased rate of myocardial infarction. Further research should assess the effectiveness and safety of these drugs in clinical practice.

Cancer pain and analgesia

Pain ranges in prevalence from 14-100% among cancer patients and occurs in 50-70% of those in active treatment. Cancer pain may result from direct invasion of tumor into nerves, bones, soft tissue, ligaments, and fascia, and may induce visceral pain through distension and obstruction. Cancer pain is multifaceted. Clinicians may describe cancer pain as acute, chronic, nociceptive (somatic), visceral, or neuropathic. Despite implementation of the WHO guidelines, reports of undertreatment of cancer pain persist in various clinical settings and in spite of decades of work to reduce unnecessary discomfort. Substantial obstacles to adequate pain relief with opioids include specific concerns of patients themselves, their family members, physicians, nurses, and the healthcare system. The WHO analgesic ladder serves as the mainstay of treatment for the relief of cancer pain in concert with tumoricidal, surgical, interventional, radiotherapeutic, psychological, and rehabilitative modalities. This multidimensional approach offers the greatest potential for maximizing analgesia and minimizing adverse effects. Primary therapies are directed at the source of the cancer pain and may enhance a patient's function, longevity, and comfort. Adjuvant therapies include nonopioids that confer analgesic effects in certain medical conditions but primarily treat conditions that do not involve pain. Nonopioid medications (over-the-counter agents) are useful in the management of mild to moderate pain, and their continuation through step 3 of the WHO ladder is an option after weighing a drug's risks and benefits in individual patients. Symptomatic treatment of severe cancer pain should begin with an opioid, regardless of the mechanism of the pain. They are very effective analgesics, titrate easily, and offer a favorable risk/benefit ratio. Cancer pain remains inadequately controlled despite the diagnostic and therapeutic means of ensuring that patients feel comfortable during their illness. Therefore, all practitioners need to make control of cancer pain a professional duty, even if they can only use the most basic and least expensive analgesic medications, such as morphine, codeine, and acetaminophen, to reduce human suffering.

Oral morphine overdose in a cancer patient antagonized by prolonged naloxone infusion

An 80-year-old male was diagnosed with carcinoma in the lung with multiple bony metastases and had been prescribed pain medications as per World Health Organization analgesic ladder guidelines. However, he was not getting adequate pain relief and there were difficulties in titration of the morphine doses on an outpatient basis. Therefore, he was hospitalized for dose titration of oral morphine and was coprescribed amitriptyline and ranitidine. During the titration of the analgesic dose, he developed severe symptoms of morphine overdose. He was immediately treated with intravenous naloxone. After prolonged infusion of naloxone, he achieved his baseline vital parameters without any permanent sequel to the overdose event. This case report describes the possible causes of oral morphine overdose in the elderly and its successful treatment. To prevent such complications, one has to be very cautious of other factors such as drug interactions, particularly in the elderly.

Opioids and the management of chronic severe pain in the elderly: consensus statement of an International Expert Panel with focus on the six clinically most often used World Health Organization Step III opioids (buprenorphine, fentanyl, hydromorphone, methadone, morphine, oxycodone)

SUMMARY OF CONSENSUS: 1. The use of opioids in cancer pain: The criteria for selecting analgesics for pain treatment in the elderly include, but are not limited to, overall efficacy, overall side-effect profile, onset of action, drug interactions, abuse potential, and practical issues, such as cost and availability of the drug, as well as the severity and type of pain (nociceptive, acute/chronic, etc.). At any given time, the order of choice in the decision-making process can change. This consensus is based on evidence-based literature (extended data are not included and chronic, extended-release opioids are not covered). There are various driving factors relating to prescribing medication, including availability of the compound and cost, which may, at times, be the main driving factor. The transdermal formulation of buprenorphine is available in most European countries, particularly those with high opioid usage, with the exception of France; however, the availability of the sublingual formulation of buprenorphine in Europe is limited, as it is marketed in only a few countries, including Germany and Belgium. The opioid patch is experimental at present in U.S.A. and the sublingual formulation has dispensing restrictions, therefore, its use is limited. It is evident that the population pyramid is upturned. Globally, there is going to be an older population that needs to be cared for in the future. This older population has expectations in life, in that a retiree is no longer an individual who decreases their lifestyle activities. The "baby-boomers" in their 60s and 70s are "baby zoomers"; they want to have a functional active lifestyle. They are willing to make trade-offs regarding treatment choices and understand that they may experience pain, providing that can have increased quality of life and functionality. Therefore, comorbidities--including cancer and noncancer pain, osteoarthritis, rheumatoid arthritis, and postherpetic neuralgia--and patient functional status need to be taken carefully into account when addressing pain in the elderly. World Health Organization step III opioids are the mainstay of pain treatment for cancer patients and morphine has been the most commonly used for decades. In general, high level evidence data (Ib or IIb) exist, although many studies have included only few patients. Based on these studies, all opioids are considered effective in cancer pain management (although parts of cancer pain are not or only partially opioid sensitive), but no well-designed specific studies in the elderly cancer patient are available. Of the 2 opioids that are available in transdermal formulation--fentanyl and buprenorphine--fentanyl is the most investigated, but based on the published data both seem to be effective, with low toxicity and good tolerability profiles, especially at low doses. 2. The use of opioids in noncancer-related pain: Evidence is growing that opioids are efficacious in noncancer pain (treatment data mostly level Ib or IIb), but need individual dose titration and consideration of the respective tolerability profiles. Again no specific studies in the elderly have been performed, but it can be concluded that opioids have shown efficacy in noncancer pain, which is often due to diseases typical for an elderly population. When it is not clear which drugs and which regimes are superior in terms of maintaining analgesic efficacy, the appropriate drug should be chosen based on safety and tolerability considerations. Evidence-based medicine, which has been incorporated into best clinical practice guidelines, should serve as a foundation for the decision-making processes in patient care; however, in practice, the art of medicine is realized when we individualize care to the patient. This strikes a balance between the evidence-based medicine and anecdotal experience. Factual recommendations and expert opinion both have a value when applying guidelines in clinical practice. 3. The use of opioids in neuropathic pain: The role of opioids in neuropathic pain has been under debate in the past but is nowadays more and more accepted; however, higher opioid doses are often needed for neuropathic pain than for nociceptive pain. Most of the treatment data are level II or III, and suggest that incorporation of opioids earlier on might be beneficial. Buprenorphine shows a distinct benefit in improving neuropathic pain symptoms, which is considered a result of its specific pharmacological profile. 4. The use of opioids in elderly patients with impaired hepatic and renal function: Functional impairment of excretory organs is common in the elderly, especially with respect to renal function. For all opioids except buprenorphine, half-life of the active drug and metabolites is increased in the elderly and in patients with renal dysfunction. It is, therefore, recommended that--except for buprenorphine--doses be reduced, a longer time interval be used between doses, and creatinine clearance be monitored. Thus, buprenorphine appears to be the top-line choice for opioid treatment in the elderly. 5. Opioids and respiratory depression: Respiratory depression is a significant threat for opioid-treated patients with underlying pulmonary condition or receiving concomitant central nervous system (CNS) drugs associated with hypoventilation. Not all opioids show equal effects on respiratory depression: buprenorphine is the only opioid demonstrating a ceiling for respiratory depression when used without other CNS depressants. The different features of opioids regarding respiratory effects should be considered when treating patients at risk for respiratory problems, therefore careful dosing must be maintained. 6. Opioids and immunosuppression: Age is related to a gradual decline in the immune system: immunosenescence, which is associated with increased morbidity and mortality from infectious diseases, autoimmune diseases, and cancer, and decreased efficacy of immunotherapy, such as vaccination. The clinical relevance of the immunosuppressant effects of opioids in the elderly is not fully understood, and pain itself may also cause immunosuppression. Providing adequate analgesia can be achieved without significant adverse events, opioids with minimal immunosuppressive characteristics should be used in the elderly. The immunosuppressive effects of most opioids are poorly described and this is one of the problems in assessing true effect of the opioid spectrum, but there is some indication that higher doses of opioids correlate with increased immunosuppressant effects. Taking into consideration all the very limited available evidence from preclinical and clinical work, buprenorphine can be recommended, while morphine and fentanyl cannot. 7. Safety and tolerability profile of opioids: The adverse event profile varies greatly between opioids. As the consequences of adverse events in the elderly can be serious, agents should be used that have a good tolerability profile (especially regarding CNS and gastrointestinal effects) and that are as safe as possible in overdose especially regarding effects on respiration. Slow dose titration helps to reduce the incidence of typical initial adverse events such as nausea and vomiting. Sustained release preparations, including transdermal formulations, increase patient compliance.

Chronic pain and opiates: a call for moderation

The prescription of opioid analgesics for chronic, nonterminal conditions continues as one of the most controversial and contentious issues in medicine. We have witnessed a full pendulum swing from the complete nihilism of the 1960s and 1970s to the careless zealotry of the 1990s. Neither extreme is good practice, and one hopes we are witnessing the dawn of a more moderate time of a sane and balanced appraisal of risk versus benefit in using these important tools.

OVERALL ARTICLE OBJECTIVE

To present the case for thoughtful attention and moderation in prescribing opioids to treat chronic pain conditions.

Constipation in cancer patients on morphine

GOALS OF WORK

Constipation is a significant problem in patients taking morphine for cancer pain. The aims of this study were (1) to assess the magnitude of constipation in this study cohort, (2) to analyse the constipation treatment strategies and (3) to look for evidence of inter-individual variation in both susceptibility to constipation and response to treatment with laxatives in this patient group.

MATERIALS AND METHODS

This was an observational study carried out in a tertiary referral cancer hospital. Two hundred seventy four patients were recruited to the study. All had a diagnosis of cancer and were on oral morphine for cancer pain. The main outcomes measured were subjective patient assessment of constipation severity in the preceding week and laxative use. Patients were asked to grade constipation in the preceding week on a four-point categorical scale: "not at all" (grade 0), "a little" (grade 1), "quite a bit" (grade 2) and "very much" (grade 3). Laxative dose groups (LDGs) were developed to assess laxative dosing.

RESULTS

Constipation affects 72% of this cohort of patients. Constipation in this population is poorly managed. Eighty nine percent of constipated patients were on inadequate laxative therapy. Inter-individual variation in constipation on morphine exists: some patients do not experience constipation and do not need to take any laxatives, some patients do not experience constipation because they are taking laxatives and some patients experience constipation despite being on high dose laxatives. These three groups were compared in terms of cancer diagnosis, time on morphine, dose of morphine and other concomitant factors. No factor was identified to account for this inter-individual variation. Improvement in the clinical management of constipation is needed, with titration of laxatives according to individual patient need.

CONCLUSION

Constipation affects a large proportion of cancer patients taking oral morphine. Constipation in these patients is generally inadequately treated.

Effect of naloxone-3-glucuronide and N-methylnaloxone on the motility of the isolated rat colon after morphine

The effect of the opioid antagonists naloxone-3-glucuronide and N-methylnaloxone on rat colon motility after morphine stimulation was measured. The rat model consisted of the isolated, vascularly perfused colon. The antagonists (10(-4) M, intraluminally) and morphine (10(-4) M, intra-arterially) were administered from 20 to 30 and from 10 to 50 min, respectively. Colon motility was determined by the luminal outflow. The antagonist concentrations in the luminal and venous outflow were measured by high-performance liquid chromatography. Naloxone-3-glucuronide and N-methylnaloxone reversed the morphine-induced reduction of the luminal outflow to baseline within 10 and 20 min, respectively. These antagonists were then excreted in the luminal outflow and could not be found in the venous samples. Naloxone, produced by hydrolysis or demethylation, was not detectable. In conclusion, highly polar naloxone derivatives peripherally antagonize the motility-lowering effect of morphine in the perfused isolated rat colon, are stable, and are not able to cross the colon-mucosal blood barrier.

Ethical and practical issues with opioids in life-limiting illness

Effective pain relief, especially at the end of life, is a primary ethical obligation based upon the principles of beneficence, nonmaleficence, patient autonomy, and particularly the concept of double effect. The pragmatic foundation of pain management begins with a complete assessment, which incorporates "WILDA" (words, intensity, location, duration, aggravating/alleviating factors) and considers the components of total pain: physical, emotional, social, and spiritual pain. Opioids are the pharmacologic sine qua non of pain management in life-limiting illness and should be prescribed based on the severity of pain, considering the functional and psychological significance of that severity. Numerous misunderstandings present a barrier to effective pain management. These misconceptions include the idea that opioids are highly addictive, that dependence or tolerance are forms of addiction, that respiratory depression is common with opioids, that opioids have a narrow therapeutic range, and that opioids are ineffective by mouth and cause too much nausea. In reality, opioids are the safest and most effective pain medicine for most moderate to severe pain in most patients. Aspects of basic opioid pharmacology, such as dosage, route of administration, rotation of drugs, and the avoidance of toxicity and complications, should be considered when initiating and maintaining therapy. Failure to pay attention to the basic rules can lead to errors in opioid management.

Brief review: Perioperative management of the patient with chronic non-cancer pain

PURPOSE

Both opioid and non-opioid medications are being utilized increasingly in the treatment of chronic non-cancer pain, and the number of surgical patients receiving large regular doses of opioids is ever-expanding. The perioperative pain control of these patients is often challenging, and is broadening the role of the anesthesiologist as 'perioperative physician'. These patients need to be identified before surgery to plan optimal pain control postoperatively. The purpose of this review is to provide an update on the important considerations in managing the chronic non-cancer pain patient receiving high dose opioids and other adjunctive medications/analgesics.

SOURCE

English language articles published between June 1980 and May 2006 were identified by a computerized Medline search using keywords (1/2)chronic pain(1/2), (1/2)opioid dependent(1/2) and (1/2)perioperative(1/2). This same search strategy was repeated and updated using both Medline and Embase. All relevant publications were retrieved and their bibliographies were scanned for additional sources.

PRINCIPAL FINDINGS

Although an increasingly common problem for the acute pain service, there is very little published on this topic. Key points include the concept of opioid equivalency, tolerance, the role of adjunctive medications, and the need for good communication between the surgical team, the acute pain service and the patient who is often anxious about the upcoming procedure due to previous unpleasant experiences with poor pain control in hospital.

CONCLUSION

Clinical care of the opioid-dependent patient in the perioperative period can be a daunting task. Education to all staff involved in this area needs to be enhanced to improve outcome and patient satisfaction.

Addiction to opioids in chronic pain patients: a literature review

Opioids have proven very useful for treatment of acute pain and cancer pain, and in the developed countries opioids are increasingly used for treatment of chronic non-malignant pain patients as well. This literature review aims at giving an overview of definitions, mechanisms, diagnostic criteria, incidence and prevalence of addiction in opioid treated pain patients, screening tools for assessing opioid addiction in chronic pain patients and recommendations regarding addiction problems in national and international guidelines for opioid treatment in cancer patients and chronic non-malignant pain patients. The review indicates that the prevalence of addiction varied from 0% up to 50% in chronic non-malignant pain patients, and from 0% to 7.7% in cancer patients depending of the subpopulation studied and the criteria used. The risk of addiction has to be considered when initiating long-term opioid treatment as addiction may result in poor pain control. Several screening tools were identified, but only a few were thoroughly validated with respect to validity and reliability. Most of the identified guidelines mention addiction as a potential problem. The guidelines in cancer pain management are concerned with the fact that pain may be under treated because of fear of addiction, and the guidelines in management of non-malignant pain patients include warnings of addiction. According to the literature, it seems appropriate and necessary to be aware of the problems associated with addiction during long-term opioid treatment, and specialised treatment facilities for pain management or addiction medicine should be consulted in these cases.

The endogenous opioid system and clinical pain management

The endogenous opioid system is one of the most studied innate pain-relieving systems. This system consists of widely scattered neurons that produce three opioids: beta-endorphin, the met- and leu-enkephalins, and the dynorphins. These opioids act as neurotransmitters and neuromodulators at three major classes of receptors, termed mu, delta, and kappa, and produce analgesia. Like their endogenous counterparts, the opioid drugs, or opiates, act at these same receptors to produce both analgesia and undesirable side effects. This article examines some of the recent findings about the opioid system, including interactions with other neurotransmitters, the location and existence of receptor subtypes, and how this information drives the search for better analgesics. We also consider how an understanding of the opioid system affects clinical responses to opiate administration and what the future may hold for improved pain relief. The goal of this article is to assist clinicians to develop pharmacological interventions that better meet their patient's analgesic needs.

Alvimopan: an oral, peripherally acting, mu-opioid receptor antagonist for the treatment of opioid-induced bowel dysfunction--a 21-day treatment-randomized clinical trial

Alvimopan has been shown to reverse the inhibitory effect of opioids on gastrointestinal transit without affecting analgesia. We evaluated oral alvimopan, 0.5 or 1 mg, versus placebo, once daily for 21 days, in 168 patients with opioid-induced bowel dysfunction (OBD) who were receiving chronic opioid therapy (minimum, 1 month) for nonmalignant pain (n = 148) or opioid dependence (n = 20). The primary outcome was the proportion of patients having at least one bowel movement (BM) within 8 hours of study drug on each day during the 21-day treatment period. Averaged over the 21-day treatment period, 54%, 43%, and 29% of patients had a BM within 8 hours after alvimopan 1 mg, 0.5 mg, or placebo, respectively (P < .001). Secondary outcomes of median times to first BM were 3, 7, and 21 hours after initial doses of 1 mg, 0.5 mg, and placebo, respectively (P < .001; 1 mg vs placebo). Weekly BMs and overall patient satisfaction were increased after the 1-mg dose (P < .001 at weeks 1 and 2 vs placebo, and P = .046, respectively). Treatment-emergent adverse events were primarily bowel-related, occurred during the first week of treatment, and were of mild to moderate severity. Alvimopan was generally well tolerated and did not antagonize opioid analgesia. Patients treated with chronic opioid therapy often experience opioid-induced bowel dysfunction as a result of undesirable effects on peripheral opioid receptors located in the gastrointestinal tract. Alvimopan, a novel peripheral opioid mu-receptor antagonist, has demonstrated significant efficacy for the management of opioid-induced bowel dysfunction without compromise of centrally mediated opioid-induced analgesia.

Strong opioids in pediatric palliative medicine

The management of pain in the palliative care of children is somewhat different from that in adults. It also differs in approach from the management of other types of acute and chronic pain in childhood. Whereas once opioids were thought to be highly dangerous drugs, unsuitable for use in children, they have now taken their place as the mainstay for provision of good analgesia to manage moderate-to-severe pain in both malignant and non-malignant life-limiting conditions. There are relatively little clinical or laboratory data regarding opioids specifically in children. However, much of what has been published regarding the management of pain in palliative medicine in adults can be extrapolated. On saying that, early research in children does suggest some significant differences in opioid pharmacokinetics, particularly with respect to morphine clearance, which seems to be faster in adults. Thus, the use of opioids in pediatric palliative care presents some unique challenges. Confident and rational use of opioids by pediatricians, illustrated by the WHO guidelines, is essential for the adequate management of pain complicating the palliative phase in children with life-limiting conditions.

ABT-594 (a nicotinic acetylcholine agonist): anti-allodynia in a rat chemotherapy-induced pain model

ABT-594 ((R)-5-(2-azetidinylmethoxy)-2-chloropyridine) represents a novel class of broad-spectrum analgesics whose primary mechanism of action is activation of the neuronal nicotinic acetylcholine receptors. The present study characterized the effects of ABT-594 in a rat chemotherapy-induced neuropathic pain model, where it attenuated mechanical allodynia with an ED50 = 40 nmol/kg (i.p.). This anti-allodynic effect was not blocked by systemic (i.p.) pretreatment with naloxone but was blocked completely with mecamylamine. Pretreatment with chlorisondamine (0.2-5 micromol/kg, i.p.) only partially blocked the effects of ABT-594 at the higher doses tested. In contrast, central (i.c.v.) pretreatment with chlorisondamine completely blocked ABT-594's anti-allodynic effect. Taken together, the data demonstrate that ABT-594 has a potent anti-allodynic effect in the rat vincristine model and that, in addition to its strong central site of action, ABT-594's effects are partially mediated by peripheral nicotinic acetylcholine receptors in this animal model of chemotherapy-induced neuropathic pain.

Opioid use by patients in an orthopedics spine clinic

OBJECTIVE

Concerns regarding the efficacy, toxicity, tolerance, dependence, and abuse of opioids have limited their use for patients with chronic spine pain. In our previous study of rheumatology clinic patients, opioid analgesics were found to be highly effective, produced only mild side effects, and had few instances of opioid abuse. The purpose of this study was to replicate our previous study in another large cohort of patients with nonmalignant pain due to well-defined spinal diseases.

METHODS

Opioid use was studied in 230 orthopedics spine clinic patients by retrospective analysis of prescriptions for 3 years and cross-sectional analysis of efficacy and toxicity by patient interviews. Opioid use and stability of the daily dose over 3 years were derived from computerized pharmacy records. Medical records, operative reports, and radiographic studies were reviewed to determine the reason for dosage escalations and to detect instances of abuse or addiction behaviors. Patients were interviewed to determine the efficacy, frequency, and types of side effects and instances of obtaining opioids from sources outside the Veterans Affairs system.

RESULTS

Opioids were prescribed for 152 of the 230 patients, for < 3 months (short-term [STO]) in 94, > or =3 months (long-term [LTO]) in 58, and none in 72 (no opioid [NTO]). Medications prescribed were codeine, oxycodone, propoxyphene, tramadol, morphine, meperidine, fentanyl, or hydroxycodone, either alone or in combination. Interviews were completed in 72 STO, 50 LTO, and 45 NTO patients. Pain severity (0-10 scale) was not different in patients with different spinal pathologies. Opioids significantly reduced the back pain severity score from 8.3 +/- 1.5 to 4.5 +/- 2.2 (mean +/- SD). Mild side effects (most commonly, constipation and sedation) were reported by 58% of the opioid-treated patients but rarely caused them to stop taking the medication. There was no significant increase from the mean +/- SD initial opioid dosage of 5.0 +/- 12.2 30-mg codeine equivalents per day (30 mg oral codeine = 5 mg oral morphine) to the mean peak dosage of 7.9 +/- 12.5 and the mean recent dosage of 4.3 +/- 6.3, suggesting that tolerance to opioid analgesia did not appear to occur in these patients. Dosage escalations of > 2 30-mg codeine equivalents occurred 19 times in 17 LTO patients and was due to worsening of the underlying painful condition, complications of spine surgery, or unrelated surgical or medical problems in all but 3 of them (5%). These 3 patients also displayed other abuse behaviors. Abuse behaviors were not more frequent in those with or without a history of abuse/addiction.

CONCLUSION

This study provides data on the efficacy, toxicity, tolerance, and abuse or addiction behaviors with opioid therapy in a large cohort of patients in an orthopedics spine clinic. The results provide objective data from patients with well-defined spine diagnoses to challenge the position that opioid treatment is inappropriate for chronic nonmalignant pain. This study provides clinical evidence to support and protect physicians treating patients with chronic musculoskeletal diseases, who may be reluctant to prescribe opioids because of possible sanctions from regulatory agencies. More important, it will benefit patients by permitting them to receive these effective, safe medications.

Underutilisation of Opioids in Elderly Patients with Chronic Pain

The impact of poorly managed chronic pain on the quality of life of elderly patients and the problems related to its management are widely acknowledged. Underutilisation of opioids is a major component of poor pain management in this group of patients, despite good evidence for the effectiveness of opioids and published guidelines directing their usage. Reasons for this underutilisation are, among others, poor assessment of pain in this age group; fear of polypharmacy and opiophobia; and avoidance of opioids because of concerns about tolerance, physical dependence, addiction and adverse effects. This review suggests approaches to overcome these barriers to opioid usage, such as regular pain assessments, education to overcome opiophobia, rational prescribing, utilisation of less conventional opioids and non-oral routes of administration, avoidance of inappropriate opioids, opioid rotation, and education about managing or preventing adverse effects, the reasons why opioid therapy may be unsuccessful, and the effects of psychological factors on the pain experience. This more rational and knowledge-based approach to the use of opioids in the management of chronic pain in the elderly population should correct the current problems with underprescribing in this age group.

Appropriate methods to assess the effectiveness and efficacy of treatments or interventions to control cancer pain

Pain is common in cancer patients. To ensure optimal pain management efficacy and effectiveness of new drugs and treatments have to be investigated in clinical trials. Efficacy trials such as randomised controlled trials (RCT) are experimental studies and estimate the maximum potential benefit to be derived from an intervention in ideal circumstances and under a controlled environment. RCTs are the only trial design to establish causal effects. A crossover study is a special type of RCT where patients serve as own controls. In efficacy studies the intervention and the control group should be as homogeneous as possible, confounding variables are controlled, bias is reduced, internal validity is high whereas external validity is low. Studies looking at effectiveness assess clinical practice and reflect real life circumstances. They rely high on external validity at the expense of careful controls, the study population is heterogeneous, confounding variables are examined. Cohort studies follow a group or groups of individuals with a common characteristic over a period of time to measure outcomes. Case-control studies start with the outcome and compare the characteristics of two groups of interest, those with the outcome and those without to identify factors which occur more or less often in the poor outcome group. Definition of outcome criteria is crucial both for efficacy and effectiveness studies and is often a primary problem. All clinical studies must use valid and reliable outcome measures.

Attenuation of mechanical allodynia by clinically utilized drugs in a rat chemotherapy-induced neuropathic pain model

Chemotherapy-induced peripheral neuropathy is a common, dose-limiting side effect of cancer chemotherapeutic agents, including the vinca alkaloids such as vincristine. The resulting symptoms, which frequently include moderate to severe pain, can often be disabling. The current study utilized a vincristine-induced neuropathic pain animal model [Pain 93 (2001) 69], in which rats were surgically implanted with mini-osmotic pumps set to deliver vincristine sulfate (30 microg kg(-1)day(-1), i.v.), to examine the time course of progression of various pain modalities and to compare the dose-response effects of clinically utilized drugs on mechanical allodynia to further validate the relevance of this model to clinical pathology. Vincristine infusion resulted in significant cold allodynia after 1 week post-infusion, however mechanical and thermal nociception showed little to no effect. In contrast, marked mechanical allodynia occurred by 1 week of vincristine infusion and returned nearly to pre-infusion levels by the 4th week after infusion pump implantation. ED(50) values (micromol/kg, p.o.) were determined in the mechanical allodynia assay for lamotrigine (82), dextromethorphan (94), gabapentin (400), acetaminophen (1100) and carbamazepine (3600); however, aspirin and ibuprofen had no effects up to 300 and 1000 micromol/kg, respectively. Additionally, ED(50) values (micromol/kg, i.p.) were determined in the mechanical allodynia assay for clonidine (0.35) and morphine (0.62), but desipramine and celecoxib had no effects up to 66 and 260 micromol/kg, respectively. Findings from the current, preclinical study further validate this model as clinically relevant for chemotherapy-induced pain. The surprisingly good effects observed with acetaminophen warrant further investigation of its mechanism(s) of action in neuropathic pain.

Use of strong opioids in advanced cancer pain: a randomized trial

The World Health Organization (WHO) guidelines for the treatment of cancer pain recommend nonopioid analgesics as first-line therapy, so-called "weak" analgesics combined with nonopioid analgesics as second-line therapy, and so-called "strong" opioids (with nonopioid analgesics) only as third-line therapy. However, these guidelines can be questioned with regard to the extent of efficacy as well as the rationale for not using strong opioids as first-line treatment, especially in terminal cancer patients. The purpose of this randomized study was to prospectively compare the efficacy and tolerability of strong opioids as first-line agents with the recommendations of the WHO in terminal cancer patients. One hundred patients with mild-moderate pain were randomized to treatment according to WHO guidelines or to treatment with strong opioids. Evaluated outcomes included pain intensity, need for change in therapy, quality of life, Karnofsky Performance Status, general condition of the patient, and adverse events. No between-treatment differences were observed for changes in quality of life or performance status, but patients started on strong opioids had significantly better pain relief than patients treated according to WHO guidelines (P=0.041). Additionally, patients started on strong opioids required significantly fewer changes in therapy, had greater reduction in pain when a change was initiated, and reported greater satisfaction with treatment than the comparator group (P=0.041). Strong opioids were safe and well-tolerated, with no development of tolerance or serious adverse events. These data suggest the utility of strong opioids for first-line treatment of pain in patients with terminal cancer.

Opioid therapy in patients with a history of substance abuse

A range of aberrant drug-taking behaviours can occur in patients who are undergoing treatment for chronic pain, especially if opioid therapy is involved. Assessing and understanding these behaviours, and their relationship to addiction (or substance use disorder), can be difficult but it is necessary for assuring quality pain management. Aberrant drug-taking behaviour may be evident, for example, when a patient with pain is unilaterally escalating doses of opioids or using the medications to treat other symptoms or when prescriptions are being mishandled. In patients with a history of substance abuse, these are often serious developments to which a clinician must know how to react. These complex behaviours may be indicative of addiction or may be simply a reaction to under-medicated pain. The clinician therefore is challenged to understand such behaviours and plan interventions accordingly. Although it is becoming increasingly common to avoid opioid therapy in patients demonstrating such challenging behaviours for fear of regulatory scrutiny, clinical management can be tailored to address the many possibilities that might be giving rise to such behaviours. In addition, control over prescriptions can be accomplished without necessarily terminating the prescribing of controlled substances entirely. Optimal medical management of chronic pain in those patients with addiction problems or engaging in problematic behaviours involves careful, ongoing assessment by the clinician as well as a tailored management approach. This approach should use multiple structures including strict contracts, prudent drug selection and frequent follow-ups to pain and addiction treatments, including the use of urine toxicology screening, to maximise the likelihood of a good outcome.