Double-blind evaluation of short-term analgesic efficacy of orally administered diclofenac, diclofenac plus codeine, and diclofenac plus imipramine in chronic cancer pain

Revision of Pharmacological Treatment Recommendations for Cancer Pain: Clinical Guidelines from the Japanese Society of Palliative Medicine

Background: Pain is one of the most common symptoms in cancer patients. The Japanese Society for Palliative Medicine (JSPM) first published its clinical guidelines for the management of cancer pain in 2010. Since then, more research on cancer pain management has been reported, and new drugs have become available in Japan. Thus, the JSPM has now revised the clinical guidelines using a validated methodology. Methods: This guideline was developed through a systematic review, discussion, and the Delphi method, following a formal guideline development process. Results: Thirty-five recommendations were created: 19 for the pharmacological management of cancer pain, 6 for the management of opioid-induced adverse effects, and 10 for pharmacological treatment procedures. Due to the lack of evidence that directly addressed our clinical questions, most of the recommendations had to be based on consensus among committee members and other guidelines. Discussion: It is critical to continue to build high-quality evidence in cancer pain management, and revise these guidelines accordingly.

Nonopioid drug combinations for cancer pain: a systematic review

Supplemental Digital Content is Available in the Text.

This review is an evaluation of the efficacy and safety of nonopioid drug combinations for cancer pain. Little evidence exists to support the use of any given agent/combination.

Pain is highly prevalent in patients with cancer—nearly 40% report moderate-severe pain, which is commonly treated with opioids. Increasing cancer survivorship, opioid epidemics in some regions of the world, and limited opioid access in other regions have focused attention on nonopioid treatments. Given the limitations of monotherapy, combining nonopioids—such as antiepileptics and antidepressants—have shown promise in noncancer pain. This review seeks to evaluate efficacy of nonopioid combinations for cancer-related pain. Systematic searches of PubMed, EMBASE, and Cochrane CENTRAL were conducted for double-blind, randomized, controlled trials comparing a nonopioid combination with at least one of its components and/or placebo. This search yielded 4 randomized controlled trials, published between 1998 and 2019 involving studies of (1) imipramine + diclofenac; (2) mitoxantrone + prednisone + clodronate; (3) pentoxifylline + tocopherol + clodronate; and (4) duloxetine + pregabalin + opioid. In the first 3 of these trials, trends favouring combination efficacy failed to reach statistical significance. However, in the fourth trial, duloxetine + pregabalin + opioid was superior to pregabalin + opioid. This review illustrates recognition for the need to evaluate nonopioid drug combinations in cancer pain, although few trials have been published to date. Given the growing practice of prescribing more than 1 nonopioid for cancer pain and the need to expand the evidence base for rational combination therapy, more high-quality trials in this area are needed.

Chronic Pain Management in Head and Neck Oncology

Pain is epidemic in patients with head and neck cancer. Providers involved in the care of patients with head and neck cancer should be able to describe the common pain syndromes experienced by these patients, identify patients at risk of pain, and provide multimodal treatment of chronic pain. Treatment of chronic pain encompasses analgesic medications; adjuvant pharmacotherapy, including antidepressants and anticonvulsants; interventional techniques; as well as integrative medicine.

Nonsteroidal anti-inflammatory drugs and pain in cancer patients: a systematic review and reappraisal of the evidence

BACKGROUND

Emerging data highlights the potential role of cyclooxygenase (COX) inhibitors in the primary prevention of malignancy, reducing metastatic spread and improving overall mortality. Despite nonsteroidal anti-inflammatory drugs (NSAIDs) forming a key component of the WHO analgesic ladder, their use in cancer pain management remains relatively low. This review re-appraises the current evidence regarding the efficacy of COX inhibitors as analgesics in cancer pain, providing a succinct resource to aid clinicians' decision making when determining treatment strategies.

METHODS

Medline® and Embase® databases were searched for publications up to November 2018. Randomised controlled trials (RCTs) and double-blind controlled studies considering the use of NSAIDs for management of cancer-related pain in adults were included. Animal studies, case reports, and retrospective observational data were excluded.

RESULTS

Thirty studies investigating the use of NSAIDs in cancer pain management were identified. There is a lack of high-quality evidence regarding the analgesic efficacy of NSAIDs in cancer pain, with short study durations and heterogeneity in outcome measures limiting the ability to draw meaningful conclusions.

CONCLUSIONS

Despite the renewed interest in these cost-effective, well-established medications in cancer treatment outcomes, there is a paucity of data from the past 15 yr regarding their efficacy in cancer pain management. However, when analgesic strategies in the cancer population are being formulated, it is important that the potential benefits of this class of drug are considered. Further work investigating the role of NSAIDs in cancer pain management is undoubtedly warranted.

Systematic review and meta-analysis on non-opioid analgesics in palliative medicine

Non-opioid analgesics are widely used for pain relief in palliative medicine. However, there is a lack of evidence-based recommendations addressing the efficacy, tolerability, and safety of non-opioids in this field. A comprehensive systematic review and meta-analysis on current evidence can provide a basis for sound recommendations in clinical practice. A database search for controlled trials on the use of non-opioids in adult palliative patients was performed in Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, PsycINFO, and EMBASE from inception to 18 February 2018. Endpoints were pain intensity, opioid-sparing effects, safety, and quality of life. Studies with similar patients, interventions, and outcomes were included in the meta-analyses. Our systematic search was able to only identify studies dealing with cancer pain. Of 5991 retrieved studies, 43 could be included (n = 2925 patients). There was no convincing evidence for satisfactory pain relief by acetaminophen alone or in combination with strong opioids. We found substantial evidence of moderate quality for a satisfactory pain relief in cancer by non-steroidal anti-inflammatory drugs (NSAIDs), flupirtine, and dipyrone compared with placebo or other analgesics. There was no evidence for a superiority of one specific non-opioid. There was moderate quality of evidence for a similar pain reduction by NSAIDs in the usual dosage range compared with up to 15 mg of morphine or opioids of equianalgesic potency. The combination of NSAID and step III opioids showed a beneficial effect, without a decreased tolerability. There is scarce evidence concerning the combination of NSAIDs with weak opioids. There are no randomized-controlled studies on the use of non-opioids in a wide range of end-stage diseases except for cancer. Non-steroidal anti-inflammatory drugs, flupirtine, and dipyrone can be recommended for the treatment of cancer pain either alone or in combination with strong opioids. The use of acetaminophen in the palliative setting cannot be recommended. Studies are not available for long-term use. There is a lack of evidence regarding pain treatment by non-opioids in specific cancer entities.

Long-term low-dose morphine for patients with moderate cancer pain is predominant factor effecting clinically meaningful pain reduction

PURPOSE

Patients with cancer often experience pain that affects their daily activities and quality of life. The analgesic ladder recommended by the World Health Organization has proved insufficient for many, and its scientific basis has been questioned. This retrospective study investigated factors related to adherence to long-term opioid therapy for patients with moderate cancer pain, including an evaluation of low-dose morphine relative to tramadol.

METHODS

Clinical data were collected of patients with moderate cancer pain (n = 353) who received either low-dose morphine or tramadol and were followed for ≥ 27 weeks. Factors related to regime adherence were investigated, including the analgesia type, cancer therapy (antitumor therapy or palliative care), pain type (nociceptive, neuropathic, or mixed), and living distance to the hospital. Factors related to clinically meaningful pain reduction (≥ 30% reduction in pain from baseline) were also investigated.

RESULTS

Patients taking tramadol, receiving antitumor therapy, experiencing neuropathic pain, and living far from the hospital were more likely to change analgesic strategy compared with, respectively, patients receiving low-dose morphine, palliative care, experiencing nociceptive pain, and living nearby. Factors that increased the likelihood of adherence to the analgesic regime were also associated with the likelihood of clinically meaningful pain reduction. Among adverse effects, a significantly higher percentage of patients experienced constipation in the tramadol group compared with those given morphine.

CONCLUSIONS

Among patients with moderate cancer pain, long-term low-dose morphine was safe and more effective than tramadol for clinically meaningful pain reduction, and patients were less likely to change the analgesic strategy.

Oral nonsteroidal anti-inflammatory drugs (NSAIDs) for cancer pain in adults

BACKGROUND

Pain is a common symptom with cancer, and 30% to 50% of all people with cancer will experience moderate to severe pain that can have a major negative impact on their quality of life. Non-opioid drugs are commonly used to treat cancer pain, and are recommended for this purpose in the World Health Organization (WHO) cancer pain treatment ladder, either alone or in combination with opioids.A previous Cochrane review that examined the evidence for nonsteroidal anti-inflammatory drugs (NSAIDs) or paracetamol, alone or combined with opioids, for cancer pain was withdrawn in 2015 because it was out of date; the date of the last search was 2005. This review, and another on paracetamol, updates the evidence.

OBJECTIVES

To assess the efficacy of oral NSAIDs for cancer pain in adults, and the adverse events reported during their use in clinical trials.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase from inception to April 2017, together with reference lists of retrieved papers and reviews, and two online study registries.

SELECTION CRITERIA

We included randomised, double-blind, single-blind, or open-label studies of five days' duration or longer, comparing any oral NSAID alone with placebo or another NSAID, or a combination of NSAID plus opioid with the same dose of the opioid alone, for cancer pain of any pain intensity. The minimum study size was 25 participants per treatment arm at the initial randomisation.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched for studies, extracted efficacy and adverse event data, and examined issues of study quality and potential bias. We did not carry out any pooled analyses. We assessed the quality of the evidence using GRADE and created a 'Summary of findings' table.

MAIN RESULTS

Eleven studies satisfied inclusion criteria, lasting one week or longer; 949 participants with mostly moderate or severe pain were randomised initially, but fewer completed treatment or had results of treatment. Eight studies were double-blind, two single-blind, and one open-label. None had a placebo only control; eight compared different NSAIDs, three an NSAID with opioid or opioid combination, and one both. None compared an NSAID plus opioid with the same dose of opioid alone. Most studies were at high risk of bias for blinding, incomplete outcome data, or small size; none was unequivocally at low risk of bias.It was not possible to compare NSAIDs as a group with another treatment, or one NSAID with another NSAID. Results for all NSAIDs are reported as a randomised cohort. We judged results for all outcomes as very low-quality evidence.None of the studies reported our primary outcomes of participants with pain reduction of at least 50%, and at least 30%, from baseline; participants with Patient Global Impression of Change (PGIC) of much improved or very much improved (or equivalent wording). With NSAID, initially moderate or severe pain was reduced to no worse than mild pain after one or two weeks in four studies (415 participants in total), with a range of estimates between 26% and 51% in individual studies.Adverse event and withdrawal reporting was inconsistent. Two serious adverse events were reported with NSAIDs, and 22 deaths, but these were not clearly related to any pain treatment. Common adverse events were thirst/dry mouth (15%), loss of appetite (14%), somnolence (11%), and dyspepsia (11%). Withdrawals were common, mostly because of lack of efficacy (24%) or adverse events (5%).

AUTHORS' CONCLUSIONS

There is no high-quality evidence to support or refute the use of NSAIDs alone or in combination with opioids for the three steps of the three-step WHO cancer pain ladder. There is very low-quality evidence that some people with moderate or severe cancer pain can obtain substantial levels of benefit within one or two weeks.

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.

Oral morphine for cancer pain

BACKGROUND

This is the third updated version of a Cochrane review first published in Issue 4, 2003 of The Cochrane Library and first updated in 2007. Morphine has been used for many years to relieve pain. Oral morphine in either immediate release or modified release form remains the analgesic of choice for moderate or severe cancer pain.

OBJECTIVES

To determine the efficacy of oral morphine in relieving cancer pain, and to assess the incidence and severity of adverse events.

SEARCH METHODS

We searched the following databases: Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 9); MEDLINE (1966 to October 2015); and EMBASE (1974 to October 2015). We also searched ClinicalTrials.gov (1 October 2015).

SELECTION CRITERIA

Published randomised controlled trials (RCTs) using placebo or active comparators reporting on the analgesic effect of oral morphine in adults and children with cancer pain. We excluded trials with fewer than 10 participants.

DATA COLLECTION AND ANALYSIS

One review author extracted data, which were checked by another review author. There were insufficient comparable data for meta-analysis to be undertaken or to produce numbers needed to treat (NNTs) for the analgesic effect. We extracted any available data on the number or proportion of participants with 'no worse than mild pain' or treatment success (very satisfied, or very good or excellent on patient global impression scales).

MAIN RESULTS

We identified seven new studies in this update. We excluded six, and one study is ongoing so also not included in this update. This review contains a total of 62 included studies, with 4241 participants. Thirty-six studies used a cross-over design ranging from one to 15 days, with the greatest number (11) for seven days for each arm of the trial. Overall we judged the included studies to be at high risk of bias because the methods of randomisation and allocation concealment were poorly reported. The primary outcomes for this review were participant-reported pain and pain relief.Fifteen studies compared oral morphine modified release (Mm/r) preparations with morphine immediate release (MIR). Fourteen studies compared Mm/r in different strengths; six of these included 24-hour modified release products. Fifteen studies compared Mm/r with other opioids. Six studies compared MIR with other opioids. Two studies compared oral Mm/r with rectal Mm/r. Three studies compared MIR with MIR by a different route of administration. Two studies compared Mm/r with Mm/r at different times and two compared MIR with MIR given at a different time. One study was found comparing each of the following: Mm/r tablet with Mm/r suspension; Mm/r with non-opioids; MIR with non-opioids; and oral morphine with epidural morphine.In the previous update, a standard of 'no worse than mild pain' was set, equivalent to a score of 30/100 mm or less on a visual analogue pain intensity scale (VAS), or the equivalent in other pain scales. Eighteen studies achieved this level of pain relief on average, and no study reported that good levels of pain relief were not attained. Where results were reported for individual participants in 17 studies, 'no worse than mild pain' was achieved by 96% of participants (362/377), and an outcome equivalent to treatment success in 63% (400/638).Morphine is an effective analgesic for cancer pain. Pain relief did not differ between Mm/r and MIR. Modified release versions of morphine were effective for 12- or 24-hour dosing depending on the formulation. Daily doses in studies ranged from 25 mg to 2000 mg with an average of between 100 mg and 250 mg. Dose titration was undertaken with both instant release and modified release products. A small number of participants did not achieve adequate analgesia with morphine. Adverse events were common, predictable, and approximately 6% of participants discontinued treatment with morphine because of intolerable adverse events.The quality of the evidence is generally poor. Studies are old, often small, and were largely carried out for registration purposes and therefore were only designed to show equivalence between different formulations.

AUTHORS' CONCLUSIONS

The conclusions have not changed for this update. The effectiveness of oral morphine has stood the test of time, but the randomised trial literature for morphine is small given the importance of this medicine. Most trials recruited fewer than 100 participants and did not provide appropriate data for meta-analysis. Only a few reported how many people had good pain relief, but where it was reported, over 90% had no worse than mild pain within a reasonably short time period. The review demonstrates the wide dose range of morphine used in studies, and that a small percentage of participants are unable to tolerate oral morphine. The review also shows the wide range of study designs, and inconsistency in cross-over designs. Trial design was frequently based on titration of morphine or comparator to achieve adequate analgesia, then crossing participants over in cross-over design studies. It was not clear if these trials were sufficiently powered to detect any clinical differences between formulations or comparator drugs. New studies added to the review for the previous update reinforced the view that it is possible to use modified release morphine to titrate to analgesic effect. There is qualitative evidence that oral morphine has much the same efficacy as other available opioids.

WITHDRAWN: NSAIDS or paracetamol, alone or combined with opioids, for cancer pain

This review is out of date, although it is correct at the date of publication. The review may be misleading as new studies could alter the original conclusions. All previous versions of the review can be found in the ‘Other versions’ tab. A new author team intends to develop four new reviews on this topic, which will serve to update and supersede this review. The new reviews will cover paracetamol, paracetamol plus opioids, NSAIDs, and NSAIDs plus opioids, for cancer pain. For more information, contact the PaPaS Review Group.

The editorial group responsible for this previously published document have withdrawn it from publication.

Codeine, alone and with paracetamol (acetaminophen), for cancer pain

BACKGROUND

Pain is very common in patients with cancer. Opioid analgesics, including codeine, play a significant role in major guidelines on the management of cancer pain, particularly for mild to moderate pain. Codeine is widely available and inexpensive, which may make it a good choice, especially in low-resource settings. Its use is controversial, in part because codeine is not effective in a minority of patients who cannot convert it to its active metabolite (morphine), and also because of concerns about potential abuse, and safety in children.

OBJECTIVES

To determine the efficacy and safety of codeine used alone or in combination with paracetamol for relieving cancer pain.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library 2014, Issue 2), MEDLINE and EMBASE from inception to 5 March 2014, supplemented by searches of clinical trial registries and screening of the reference lists of the identified studies and reviews in the field.

SELECTION CRITERIA

We sought randomised, double-blind, controlled trials using single or multiple doses of codeine, with or without paracetamol, for the treatment of cancer pain. Trials could have either parallel or cross-over design, with at least 10 participants per treatment group. Studies in children or adults reporting on any type, grade, and stage of cancer were eligible. We accepted any formulation, dosage regimen, and route of administration of codeine, and both placebo and active controls.

DATA COLLECTION AND ANALYSIS

Two review authors independently read the titles and abstracts of all studies identified by the searches and excluded those that clearly did not meet the inclusion criteria. For the remaining studies, two authors read the full manuscripts and assessed them for inclusion. We resolved discrepancies between review authors by discussion. Included studies were described qualitatively, since no meta-analysis was possible because of the small amount of data identified, and clinical and methodological between-study heterogeneity.

MAIN RESULTS

We included 15 studies including 721 participants with cancer pain due to diverse types of malignancy. All studies were performed on adults; there were no studies on children. The included studies were of adequate methodological quality, but all except for one were judged to be at a high risk of bias because of small study size, and six because of methods used to deal with missing data or high withdrawal rates. Three studies used a parallel group design; the remainder were cross-over trials in which there was an adequate washout period, but only one reported results for treatment periods separately.Twelve studies used codeine as a single agent and three combined it with paracetamol. Ten studies included a placebo arm, and 14 included one or more of 16 different active drug comparators or compared different routes of administration. Most studies investigated the effect of a single dose of medication, while five used treatment periods of one, seven or 21 days. Most studies used codeine at doses of 30 mg to 120 mg.There were insufficient data for any pooled analysis. Only two studies reported our preferred responder outcome of 'participants with at least 50% reduction in pain' and two reported 'participants with no worse than mild pain'. Eleven studies reported treatment group mean measures of pain intensity or pain relief; overall for these outcome measures, codeine or codeine plus paracetamol was numerically superior to placebo and equivalent to the active comparators.Adverse event reporting was poor: only two studies reported the number of participants with any adverse event specified by treatment group and only one reported the number of participants with any serious adverse event. In multiple-dose studies nausea, vomiting and constipation were common, with somnolence and dizziness frequent in the 21-day study. Withdrawal from the studies, where reported, was less than 10% except in two studies. There were three deaths, in all cases due to the underlying cancer.

AUTHORS' CONCLUSIONS

We identified only a small amount of data in studies that were both randomised and double-blind. Studies were small, of short duration, and most had significant shortcomings in reporting. The available evidence indicates that codeine is more effective against cancer pain than placebo, but with increased risk of nausea, vomiting, and constipation. Uncertainty remains as to the magnitude and time-course of the analgesic effect and the safety and tolerability in longer-term use. There were no data for children.

Imipramine for neuropathic pain in adults

BACKGROUND

Antidepressants are widely used to treat chronic neuropathic pain (pain due to nerve damage), usually in doses below those at which they exert antidepressant effects. An earlier review that included all antidepressants for neuropathic pain is being replaced by new reviews of individual drugs examining individual neuropathic pain conditions.Imipramine is a tricyclic antidepressant that is occasionally used to treat neuropathic pain.

OBJECTIVES

To assess the analgesic efficacy of imipramine for chronic neuropathic pain in adults, and to assess the associated adverse events.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and EMBASE on 18 November 2013, as well as the reference lists of retrieved papers and other reviews. We also used our own handsearched database for older studies, and two clinical trials databases.

SELECTION CRITERIA

We included randomised, double-blind studies of at least two weeks' duration comparing imipramine with placebo or another active treatment in chronic neuropathic pain. Participants were adults aged 18 and over. We included only articles with full journal publication and extended trial abstracts and summaries.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted efficacy and adverse event data, and examined issues of study quality. We performed analysis using three tiers of evidence. First tier evidence was derived from data meeting current best standards and subject to minimal risk of bias (outcome equivalent to substantial pain intensity reduction, intention-to-treat analysis without imputation for dropouts; at least 200 participants in the comparison, 8 to 12 weeks duration, parallel design); second tier from data that failed to meet one or more of these criteria and were considered at some risk of bias but with adequate numbers in the comparison; and third tier from data involving small numbers of participants which was considered very likely to be biased or used outcomes of limited clinical utility, or both.

MAIN RESULTS

Five studies treated 168 participants with painful diabetic neuropathy or polyneuropathy. The mean age in individual studies was between 47 and 56 years. Four studies used a cross-over, and one a parallel group design; 126 participants were randomised to receive imipramine 25 mg to 350 mg daily (most took 100 mg to 150 mg daily). Comparators were placebo (an active placebo in one study), paroxetine, mianserin, venlafaxine, and amitriptyline, and treatment was given for 2 to 12 weeks. All studies had one or more sources of potential major bias.No study provided first or second tier evidence for any outcome. No data were available on the proportion of people with at least 50% or 30% reduction in pain or equivalent, and data were available from only one study for our other primary outcome of Patient Global Impression of Change, reported as patient evaluation of pain relief of complete or good. No pooling of data was possible, but third tier evidence in individual studies indicated some improvement in pain relief with imipramine compared with placebo, although this is was very low quality evidence, derived mainly from group mean data and completer analyses, in small, short duration studies where major bias is possible.Four studies reported some information about adverse events, but reporting was inconsistent and fragmented, and the quality of evidence was very low. Participants taking imipramine generally experienced more adverse events, notably dry mouth, and a higher rate of withdrawal due to adverse events, than did participants taking placebo.

AUTHORS' CONCLUSIONS

This review found little evidence to support the use of imipramine to treat neuropathic pain. There was very low quality evidence of benefit but this came from studies that were methodologically flawed and potentially subject to major bias. Effective medicines with much greater supportive evidence are available.

Oral morphine for cancer pain

BACKGROUND

This is the second updated version of a Cochrane review first published in Issue 4, 2003 of The Cochrane Library and first updated in 2007. Morphine has been used for many years to relieve pain. Oral morphine in either immediate release or modified release form remains the analgesic of choice for moderate or severe cancer pain.

OBJECTIVES

To determine the efficacy of oral morphine in relieving cancer pain, and assess the incidence and severity of adverse effects.

SEARCH METHODS

We searched the following databases: Cochrane Pain, Palliative and Supportive Care Group Trials Register (June 2013); Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 5, May); MEDLINE (1966 to June 2013); and EMBASE (1974 to June 2013).

SELECTION CRITERIA

Published randomised controlled trials (RCTs) using placebo or active comparators reporting on the analgesic effect of oral morphine in adults and children with cancer pain. Trials with fewer than ten participants were excluded.

DATA COLLECTION AND ANALYSIS

One review author extracted data, which were checked by another review author. There were insufficient comparable data for meta-analysis to be undertaken or to produce numbers needed to treat (NNTs) for the analgesic effect. We extracted any available data on the number or proportion of participants with 'no worse than mild pain' or treatment success (very satisfied, or very good or excellent on patient global impression scales).

MAIN RESULTS

Ten new studies (638 participants) were identified for this update, bringing the total of included studies to 62, with 4241 participants. Thirty-six studies used a cross-over design ranging from one to 15 days, with the greatest number (11) for seven days for each arm of the trial.Fifteen studies compared oral morphine modified release (Mm/r) preparations with morphine immediate release (MIR). Fourteen studies compared Mm/r in different strengths; six of these included 24-hour modified release products. Fifteen studies compared Mm/r with other opioids. Six studies compared MIR with other opioids. Two studies compared oral Mm/r with rectal Mm/r. Three studies compared MIR with MIR by a different route of administration. Two studies compared Mm/r with Mm/r at different times and two compared MIR with MIR given at a different time. One study was found comparing each of the following: Mm/r tablet with Mm/r suspension; Mm/r with non-opioids; MIR with non-opioids; and oral morphine with epidural morphine.In this update a standard of 'no worse than mild pain' was set equivalent to a score of 30/100 mm or less on a visual analogue pain intensity scale (VAS), or the equivalent in other pain scales. Eighteen studies achieved this level of pain relief on average, and no study reported that good levels of pain relief were not attained. Where results were reported for individual participants in 17 studies, 'no worse than mild pain' was achieved by 96% of participants (362/377), and an outcome equivalent to treatment success in 63% (400/638).Morphine is an effective analgesic for cancer pain. Pain relief did not differ between Mm/r and MIR. Modified release versions of morphine were effective for 12- or 24-hour dosing depending on the formulation. Daily doses in studies ranged from 25 mg to 2000 mg with an average of between 100 mg and 250 mg. Dose titration was undertaken with both instant release and modified release products. A small number of participants did not achieve adequate analgesia with morphine. Adverse effects were common and approximately 6% of participants discontinued treatment because of intolerable adverse effects.

AUTHORS' CONCLUSIONS

The effectiveness of oral morphine has stood the test of time, but the randomised trial literature for morphine is small given the importance of this medicine. Most trials recruited fewer than 100 participants and did not provide appropriate data for meta-analysis. Only a few reported how many people had good pain relief, but where it was reported, over 90% had no worse than mild pain within a reasonably short time period. The review demonstrates the wide dose range of morphine used in studies, and that a small percentage of participants are unable to tolerate oral morphine. The review also shows the wide range of study designs, and inconsistency in cross-over designs. Trial design was frequently based on titration of morphine or comparator to achieve adequate analgesia, then crossing participants over in cross-over design studies. It was not clear if these trials are sufficiently powered to detect any clinical differences between formulations or comparator drugs. New studies added to the review reinforce the view that it is possible to use modified release morphine to titrate to analgesic effect. There is qualitative evidence that oral morphine has much the same efficacy as other available opioids.

Flupirtine enhances the anti-hyperalgesic effects of morphine in a rat model of prostate bone metastasis

OBJECTIVE

Current treatments for cancer pain are often inadequate, particularly when metastasis to bone is involved. The addition to the treatment regimen of another drug that has a complementary analgesic effect may increase the overall analgesia without the necessity to increase doses, thus avoiding dose-related side effects. This project investigated the synergistic effect of the addition of the potassium channel (KCNQ2-3) modulator flupirtine to morphine treatment in a rat model of prostate cancer-induced bone pain.

DESIGN

Syngeneic prostate cancer cells were injected into the right tibia of male Wistar rats under anesthesia. This led to expanding tumor within the bone in 2 weeks, together with the concurrent development of hyperalgesia to noxious heat. Paw withdrawal thresholds from noxious heat were measured before and after the maximum non-sedating doses of morphine and flupirtine given alone and in combinations. Dose-response curves for morphine (0.13-5.0 mg/kg ip) and flupirtine (1.25-10.0 mg/kg ip) given alone and in fixed-dose combinations were plotted and subjected to an isobolographic analysis.

RESULTS

Both morphine (ED₅₀ = 0.74 mg/kg) and flupirtine (ED₅₀ = 3.32 mg/kg) caused dose-related anti-hyperalgesia at doses that did not cause sedation. Isobolographic analysis revealed that there was a synergistic interaction between flupirtine and morphine. Addition of flupirtine to morphine treatment improved morphine anti-hyperalgesia, and resulted in the reversal of cancer-induced heat hyperalgesia.

CONCLUSIONS

These results suggest that flupirtine in combination with morphine may be useful clinically to provide better analgesia at lower morphine doses in the management of pain caused by tumors growing in bone.

Combination pharmacotherapy for the treatment of neuropathic pain in adults

BACKGROUND

Pharmacotherapy remains an important modality for the treatment of neuropathic pain. However, as monotherapy current drugs are associated with limited efficacy and dose-related side effects. Combining two or more different drugs may improve analgesic efficacy and, in some situations, reduce overall side effects (e.g. if synergistic interactions allow for dose reductions of combined drugs).

OBJECTIVES

This review evaluated the efficacy, tolerability and safety of various drug combinations for the treatment of neuropathic pain.

SEARCH METHODS

We identified randomised controlled trials (RCTs) of various drug combinations for neuropathic pain from CENTRAL, MEDLINE, EMBASE and handsearches of other reviews and trial registries. The most recent search was performed on 9 April 2012.

SELECTION CRITERIA

Double-blind, randomised studies comparing combinations of two or more drugs (systemic or topical) to placebo and/or at least one other comparator for the treatment of neuropathic pain.

DATA COLLECTION AND ANALYSIS

Data extracted from each study included: proportion of participants a) reporting ≥ 30% pain reduction from baseline OR ≥ moderate pain relief OR ≥ moderate global improvement; b) dropping out of the trial due to treatment-emergent adverse effects; c) reporting each specific adverse effect (e.g. sedation, dizziness) of ≥ moderate severity. The primary comparison of interest was between study drug(s) and one or both single-agent comparators. We combined studies if they evaluated the same drug class combination at roughly similar doses and durations of treatment. We used RevMan 5 to analyse data for binary outcomes.

MAIN RESULTS

We identified 21 eligible studies: four (578 participants) evaluated the combination of an opioid with gabapentin or pregabalin; two (77 participants) evaluated an opioid with a tricyclic antidepressant; one (56 participants) of gabapentin and nortriptyline; one (120 participants) of gabapentin and alpha-lipoic acid, three (90 participants) of fluphenazine with a tricyclic antidepressant; three (90 participants) of an N-methyl-D-aspartate (NMDA) blocker with an agent from a different drug class; five (604 participants) of various topical medications; one (313 participants) of tramadol with acetaminophen; and another one (44 participants) of a cholecystokinin blocker (L-365,260) with morphine. The majority of combinations evaluated to date involve drugs, each of which share some element of central nervous system (CNS) depression (e.g. sedation, cognitive dysfunction). This aspect of side effect overlap between the combined agents was often reflected in similar or higher dropout rates for the combination and may thus substantially limit the utility of such drug combinations. Meta-analysis was possible for only one comparison of only one combination, i.e. gabapentin + opioid versus gabapentin alone. This meta-analysis involving 386 participants from two studies demonstrated modest, yet statistically significant, superiority of a gabapentin + opioid combination over gabapentin alone. However, this combination also produced significantly more frequent side effect-related trial dropouts compared to gabapentin alone.

AUTHORS' CONCLUSIONS

Multiple, good-quality studies demonstrate superior efficacy of two-drug combinations. However, the number of available studies for any one specific combination, as well as other study factors (e.g. limited trial size and duration), preclude the recommendation of any one specific drug combination for neuropathic pain. Demonstration of combination benefits by several studies together with reports of widespread clinical polypharmacy for neuropathic pain surely provide a rationale for additional future rigorous evaluations. In order to properly identify specific drug combinations which provide superior efficacy and/or safety, we recommend that future neuropathic pain studies of two-drug combinations include comparisons with placebo and both single-agent components. Given the apparent adverse impact of combining agents with similar adverse effect profiles (e.g. CNS depression), the anticipated development and availability of non-sedating neuropathic pain agents could lead to the identification of more favourable analgesic drug combinations in which side effects are not compounded.

Combination drug therapy for chronic pain: a call for more clinical studies

Chronic pain is a debilitating clinical condition associated with a variety of disease entities including diabetic neuropathy, postherpetic neuralgia, low back pathology, fibromyalgia, and neurological disorders. For many general practitioners and specialists, managing chronic pain has become a daunting challenge. As a modality of multidisciplinary chronic pain management, medications are often prescribed in combinations, an approach referred to as combination drug therapy (CDT). However, many medications for pain therapy, including antidepressants and opioid analgesics, have significant side effects that can compound when used in combination and impact the effectiveness of CDT. To date, clinical practice of CDT for chronic pain has been based largely on clinical experiences. In this article, we will focus on (1) the scientific basis and rationales for CDT, (2) current clinical data on CDT, and (3) the need for more clinical studies to establish a framework for the use of CDT.

PERSPECTIVE

More preclinical, clinical, and translational studies are needed to improve the efficacy of combination drug therapy that is an integral part of a comprehensive approach to the management of chronic pain.

Gastroprotection and effect of the simultaneous administration of Cuachalalate (Amphipterygium adstringens) on the pharmacokinetics and anti-inflammatory activity of diclofenac in rats

This work aimed to study the effect of Cuachalalate methanol extract (CME) on the anti-inflammatory activity and pharmacokinetics of diclofenac sodium, a frequently prescribed non-steroidal antiinflammatory drug (NSAID). The gastroprotective effect of CME on the gastric injury induced by diclofenac was studied in rats. CME showed a gastroprotective effect of 15.7% at 1 mg kg−1 and 72.5% at dose of 300 mg kg−1. Omeprazole, used as anti-ulcer reference drug, showed gastroprotective effects of 50–89.7% at doses tested (1–30 mg kg−1). The value of the 50% effective dose for the anti-inflammatory effect of diclofenac sodium (ED50 = 1.14 ± 0.23 mg kg−1) using carrageenaninduced rat paw oedema model, was not modified by the concomitant administration of 30 or 100 mg kg−1 of CME. The effect of CME (30, 100 and 300 mg kg−1, p.o.) on the pharmacokinetics of diclofenac sodium was studied. It was observed that the simultaneous administration of diclofenac sodium and 300 mg kg−1 of CME decreased significantly the values of Cmax (7.08 ± 1.42 μg mL−1) and AUC (12.67 ± 2.97 μg h mL−1), but not the value of tmax (0.13 (0.1–0.25) h) obtained with the administration of diclofenac alone. The simultaneous administration of 30 or 100 mg kg−1 of CME did not modify the pharmacokinetic parameters of diclofenac. The experimental findings in rats suggest that CME at doses lower than 100 mg kg−1 protects the gastric mucosa from the damage induced by diclofenac sodium without altering either the anti-inflammatory activity or the pharmacokinetics of this NSAID.

Translational medicine: cancer pain mechanisms and management

Cancer-induced bone pain (CIBP) is a major clinical problem with up to 85% of patients with bony metastases having pain, often associated with anxiety and depression, reduced performance status, and a poor quality of life. Malignant bone disease creates a chronic pain state through sensitization and synaptic plasticity within the spinal cord that amplifies nociceptive signals and their transmission to the brain. Fifty per cent of patients are expected to gain adequate analgesia from palliative radiotherapy within 4-6 weeks of treatment. Opioid analgesia does make a useful contribution to the management of CIBP, especially in terms of suppressing tonic background pain. However, CIBP remains a clinical challenge because the spontaneous and movement-related components are more difficult to treat with opioids and commonly used analgesic drugs, without unacceptable side-effects. Recently developed laboratory models of CIBP, which show congruency with the clinical syndrome, are contributing to an improved understanding of the neurobiology of CIBP. This chronic pain syndrome appears to be unique and distinct from other chronic pain states, such as inflammatory or neuropathic pain. This has clear implications for treatment and development of future therapies. A translational medicine approach, using a highly iterative process between the clinic and the laboratory, may allow improved understanding of the underlying mechanisms of CIBP to be rapidly translated into real clinical benefits in terms of improved pain management.

Oral morphine for cancer pain

BACKGROUND

This is an updated version of a previous Cochrane review first published in Issue 4, 2003 of The Cochrane Library. Morphine has been used for many years to relieve pain. Oral morphine in either immediate release or modified release form remains the analgesic of choice for moderate or severe cancer pain.

OBJECTIVES

To determine the efficacy of oral morphine in relieving cancer pain and to assess the incidence and severity of adverse effects.

SEARCH STRATEGY

The following databases were searched: Cochrane Pain, Palliative and Supportive Care Group Trials Register (December 2006); Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2006, Issue 4); MEDLINE (1966 to December 2006); and EMBASE (1974 to December 2006).

SELECTION CRITERIA

Published randomised controlled trials (RCTs) reporting on the analgesic effect of oral morphine in adults and children with cancer pain. Any comparator trials were considered. Trials with fewer than ten participants were excluded.

DATA COLLECTION AND ANALYSIS

One review author extracted data, which was checked by the other review author. There were insufficient comparable data for meta-analysis to be undertaken or to produce numbers-needed-to-treat (NNT) for the analgesic effect.

MAIN RESULTS

In this update, nine new studies with 688 participants were added. Fifty-four studies (3749 participants) met the inclusion criteria. Fifteen studies compared oral modified release morphine (Mm/r) preparations with immediate release morphine (MIR). Twelve studies compared Mm/r in different strengths, five of these included 24-hour modified release products. Thirteen studies compared Mm/r with other opioids. Six studies compared MIR with other opioids. Two studies compared oral Mm/r with rectal Mm/r. Two studies compared MIR with MIR by a different route of administration. One study was found comparing each of the following: Mm/r tablet with Mm/r suspension; Mm/r with non-opioids; MIR with non-opioids; and oral morphine with epidural morphine. Morphine was shown to be an effective analgesic. Pain relief did not differ between Mm/r and MIR. Modified release versions of morphine were effective for 12 or 24-hour dosing depending on the formulation. Daily doses in studies ranged from 25 mg to 2000 mg with an average of between 100 mg and 250 mg. Dose titration were undertaken with both instant release and modified release products. Adverse effects were common but only 4% of patients discontinued treatment because of intolerable adverse effects.

AUTHORS' CONCLUSIONS

The randomised trial literature for morphine is small given the importance of this medicine. Most trials recruited fewer than 100 participants and did not provide appropriate data for meta-analysis. Trial design was frequently based on titration of morphine or comparator to achieve adequate analgesia, then crossing participants over in crossover design studies. It was not clear if these trials are sufficiently powered to detect any clinical differences between formulations or comparator drugs. Studies added to the review reinforce the view that it is possible to use modified release morphine to titrate to analgesic effect. There is qualitative evidence for effectiveness of oral morphine which compares well to other available opioids. There is limited evidence to suggest that transmucosal fentanyl provides more rapid pain relief for breakthrough pain compared to morphine.

Antidepressants for neuropathic pain

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 3, 2005 of The Cochrane Library. For many years antidepressant drugs have been used to manage neuropathic pain, and are often the first choice treatment. It is not clear, however, which antidepressant is more effective, what role the newer antidepressants can play in treating neuropathic pain, and what adverse effects are experienced by patients.

OBJECTIVES

To determine the analgesic effectiveness and safety of antidepressant drugs in neuropathic pain.

SEARCH STRATEGY

Randomised controlled trials (RCTs) of antidepressants in neuropathic pain were identified in MEDLINE (1966 to Oct 2005); EMBASE (1980 to Oct 2005); the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, Issue 3, 2005; and the Cochrane Pain, Palliative and Supportive Care Trials Register (May 2002). Additional reports were identified from the reference list of the retrieved papers, and by contacting investigators.

SELECTION CRITERIA

RCTs reporting the analgesic effects of antidepressant drugs in adult patients, with subjective assessment of pain of neuropathic origin. Studies that included patients with chronic headache and migraine were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors agreed the included studies, extracted data, and assessed methodological quality independently. Sixty one trials of 20 antidepressants were considered eligible (3293 participants) for inclusion. Relative Risk (RR) and Number-Needed-to-Treat (NNTs) were calculated from dichotomous data for effectiveness and adverse effects. This update includes 11 additional studies (778 participants).

MAIN RESULTS

Sixty one RCTs were included in total. Tricyclic antidepressants (TCAs) are effective and have an NNT of 3.6 (95% CI 3 to 4.5) RR 2.1 (95% CI 1.8 to 2.5) for the achievement of at least moderate pain relief. There is limited evidence for the effectiveness of the newer SSRIs but no studies of SNRIs were found. Venlafaxine (three studies) has an NNT of 3.1 (95% CI 2.2 to 5.1) RR 2.2 (95% CI 1.5 to 3.1). There were insufficient data to assess effectiveness for other antidepressants such as St Johns Wort and L-tryptophan. For diabetic neuropathy the NNT for effectiveness was 1.3 (95% CI 1.2 to 1.5) RR 12.4 (95% CI 5.2 to 29.2) (five studies); for postherpetic neuralgia 2.7 (95% CI 2 to 4.1), RR 2.2 (95% CI 1.6 to 3.1) (four studies). There was evidence that TCAs are not effective in HIV-related neuropathies. The number needed to harm (NNH) for major adverse effects defined as an event leading to withdrawal from a study was 28 (95% CI 17.6 to 68.9) for amitriptyline and 16.2 (95% CI 8 to 436) for venlafaxine. The NNH for minor adverse effects was 6 (95% CI 4.2 to 10.7) for amitriptyline and 9.6 (95% CI 3.5 to 13) for venlafaxine.

AUTHORS' CONCLUSIONS

This update has provided additional confirmation on the effectiveness of antidepressants for neuropathic pain and has provided new information on another antidepressant - venlafaxine. There is still limited evidence for the role of SSRIs. Whether antidepressants prevent the development of neuropathic pain (pre-emptive use) is still unclear. Both TCAs and venlafaxine have NNTs of approximately three. This means that for approximately every three patients with neuropathic pain who are treated with either of these antidepressants, one will get at least moderate pain relief. There is evidence to suggest that other antidepressants may be effective but numbers of participants are insufficient to calculate robust NNTs. SSRIs are generally better tolerated by patients and more high quality studies are required.

Weak opioids--an educational substitute for morphine?

The World Health Organization guidelines suggest the use of weak opioids on the second step of the analgesic ladder for cancer pain relief. Weak opioids are important substitutes for low doses of morphine, although their analgesic efficacy is lower than that of non-opioid or strong opioid analgesics. The use of weak opioids has great educational impact and has helped spread the use of the guidelines. Furthermore, weak opioids are more freely available and are expected to have a better side-effect profile. Controlled long-term studies are required for confirmation.

Effects of Analgesic or Antidepressant Drugs on Pain- or Stress-Evoked Hippocampal and Spinal Neurokinin-1 Receptor and Brain-Derived Neurotrophic Factor Gene Expression in the Rat

Clinical studies show that people suffering from chronic pain are often also burdened by depression. Antidepressants are used to treat some types of chronic pain; however, little is known about their mechanisms of action. This study addressed the effects of a nonsteroidal anti-inflammatory drug and a tricyclic antidepressant drug on pain- and stress-evoked gene expression in the rat spinal cord dorsal horn and hippocampus. Rats were pretreated with either indomethacin or imipramine and then challenged with either intraplantar complete Freund's adjuvant or a bout of immobilization stress. Results showed that indomethacin significantly reduced nociception-related peripheral edema, hyperalgesia, and reversed the pain-evoked up-regulation of neurokinin (NK)-1 receptor and brain-derived neurotrophic factor (BDNF) gene expression in the spinal cord to levels not statistically different from controls. However, indomethacin did not protect against significant pain-induced down-regulation of these genes in the hippocampus by approximately 50%, suggesting that although analgesic drug treatment reduces nociceptive sensory activation in the spinal cord, it is insufficient to prevent the impact of pain on the hippocampus. Conversely, although imipramine did not provide significant behavioral analgesia, it significantly blocked both pain- and stress-evoked alterations in hippocampal and spinal NK-1 and BDNF gene expression. Thus, these results show that application of either analgesic or antidepressant drugs alone does not fully protect against both the behavioral and molecular effects of persistent pain on both "sensory" and "affective" processing within the central nervous system.

Antidepressants for neuropathic pain

BACKGROUND

For many years antidepressant drugs have been used to manage neuropathic pain, and are often the first choice treatment. It is not clear, however, which antidepressant is more effective, what role the newer antidepressants can play in treating neuropathic pain, and what adverse effects are experienced by patients.

OBJECTIVES

To determine the analgesic effectiveness and safety of antidepressant drugs in neuropathic pain. Migraine and headache studies were not considered.

SEARCH STRATEGY

Randomised trials of antidepressants in neuropathic pain were identified in MEDLINE (1966 to Dec 2003); EMBASE (1980 to Dec 2003); the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library 2004, Issue 1; and the Cochrane Pain, Palliative and Supportive Care Trials Register (May 2002). Additional reports were identified from the reference list of the retrieved papers, and by contacting investigators.

SELECTION CRITERIA

Randomised trials reporting the analgesic effects of antidepressant drugs in adult patients, with subjective assessment of pain of neuropathic origin. Studies that included patients with chronic headache and migraine were excluded.

DATA COLLECTION AND ANALYSIS

Two reviewers agreed the included studies, extracted data, and assessed methodological quality independently. Fifty trials of 19 antidepressants were considered eligible (2515 patients) for inclusion. Relative Risk (RR) estimates and Number-Needed-to-Treat (NNTs) were calculated from dichotomous data for effectiveness and adverse effects.

MAIN RESULTS

Tricyclic antidepressants (TCAs) are effective treatments for the treatment of neuropathic pain. Amitriptyline has an NNT of 2 (95%CI 1.7 to 2.5) RR 4.1(95%CI 2.9-5.9) for the achievement of at least moderate pain relief. There is limited evidence for the effectiveness of the newer selective serotonin reuptake inhibitor antidepressant drugs (SSRIs). There were insufficient data for an assessment of evidence of effectiveness for other antidepressants such as St Johns Wort, venlafaxine and L-tryptophan. For diabetic neuropathy the NNT for effectiveness was 1.3 (95%CI 1.2 to 1.5) RR 12.4(95%CI 5.2-29.2) (five studies); for postherpetic neuralgia 2.2 (95%CI 1.7 to 3.1), RR 4.8(95%CI 2.5-9.5)(three studies). There was evidence that TCAs are not effective in HIV-related neuropathies. The number needed to harm(NNH) for major adverse effects defined as an event leading to withdrawal from a study was 16 (95%CI: 10-45). The NNH for minor adverse effects was 4.6 (95%CI 3.3-6.7)

AUTHORS' CONCLUSIONS

Antidepressants are effective for a variety of neuropathic pains. The best evidence available is for amitriptyline. There are only limited data for the effectiveness of SSRIs. It is not possible to identify the most effective antidepressant until more studies of SSRIs are conducted.

A validation study of the WHO analgesic ladder: a two-step vs three-step strategy

GOALS OF WORK

The aims of the present study were to verify whether an innovative therapeutic strategy for the treatment of mild-moderate chronic cancer pain, passing directly from step I to step III of the WHO analgesic ladder, is more effective than the traditional three-step strategy and to evaluate the tolerability and therapeutic index in both strategies.

METHODS

Patients aged 18 years or older with multiple viscera or bone metastases or with locally advanced disease were randomized. Pain intensity was assessed using a 0-10 numerical rating scale based on four questions selected from the validated Italian version of the Brief Pain Inventory. Treatment-specific variables and other symptoms were recorded at baseline up to a maximum follow-up of 90 days per patient.

RESULTS

Fifty-four patients were randomized onto the study, and pain intensity was assessed over a period of 2,649 days. The innovative treatment presented a statistically significant advantage over the traditional strategy in terms of the percentage of days with worst pain > or =5 (22.8 vs 28.6%, p < 0.001) and > or =7 (8.6 vs 11.2%, p = 0.023). Grades 3 and 4 anorexia and constipation were more frequently reported in the innovative strategy arm, although prophylactic laxative therapy was used less in this setting.

CONCLUSIONS

Our preliminary data would seem to suggest that a direct move to the third step of the WHO analgesic ladder is feasible and could reduce some pain scores but also requires careful management of side effects.

NSAIDS or paracetamol, alone or combined with opioids, for cancer pain

BACKGROUND

NSAIDs are widely applied to treat cancer pain and are frequently combined with opioids in combination preparations for this purpose. However, it is unclear which agent is most clinically efficacious for relieving cancer-related pain, or even what may be the additional benefit of combining an NSAID with an opioid in this setting.

OBJECTIVES

To assess the effects of NSAIDs, alone or combined with opioids, for the treatment of cancer pain.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (Issue 2, 2002), MEDLINE (January 1966 to March 2003), EMBASE (January 1980 to December 2001), LILACS (January 1984 to December 2001) and reference list of articles.

SELECTION CRITERIA

Randomized controlled trials and controlled clinical trials that compared NSAID versus placebo; NSAID versus NSAID; NSAID versus NSAID plus opioid; opioid versus opioid plus NSAID; or NSAID versus opioid.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information. Adverse event information was collected from trials. Where there was disagreement between reviewers, the opinion of an additional reviewer was sought to resolve the issue.

MAIN RESULTS

Forty-two trials involving 3084 patients were included. Clinical heterogeneity of study methods and outcomes precluded meta-analyses and only supported a qualitative systematic review. Seven of eight papers that compared NSAID with placebo demonstrated superior efficacy of NSAID with no difference in side effects. Thirteen papers compared one NSAID with another; four reported increased efficacy of one NSAID over another. Four different studies found that one NSAID had fewer side effects than one or more others. Twenty-three studies compared NSAIDs and opioids in combination or alone with NSAID/opioid combinations. Thirteen out of 14 studies found no difference, or low clinical difference, when combining an NSAID plus an opioid versus either drug alone. Comparisons between various NSAID/opioid combinations were inconclusive. Nine studies assessed the association between dose and efficacy and safety. Four papers demonstrated increased efficacy with increased dose, but no dose-dependent increase in side effects within the dose ranges studied. Study duration ranged from single dose studies performed over six hours to crossover studies lasting six weeks; however the majority of studies were of less than seven days duration.

AUTHORS' CONCLUSIONS

Based upon limited data, NSAIDs appear to be more effective than placebo for cancer pain; clear evidence to support superior safety or efficacy of one NSAID over another is lacking; and trials of combinations of an NSAID with an opioid have disclosed either no difference (4 out of 14 papers), a statistically insignificant trend towards superiority (1 out of 14 papers), or at most a slight but statistically significant advantage (9 out of 14 papers), compared with either single entity. The short duration of studies undermines generalization of their findings on efficacy and safety of NSAIDs for cancer pain.

Nonsteroidal Anti-Inflammatory Drugs, Alone or Combined With Opioids, for Cancer Pain

Purpose

To assess the safety and efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs), alone or combined with opioids, for the treatment of cancer pain.

Patients and Methods

Forty-two trials involving 3,084 patients met inclusion criteria: eight compared NSAID with placebo; 13 compared one NSAID with another; 23 compared NSAID with opioid, NSAID or opioid versus NSAID plus opioid combinations, or NSAID plus opioid combinations versus NSAID plus opioid combinations; and nine studies assessed the effect of increasing NSAID dose.

Results

Sixteen studies lasted 1 week or longer and 11 evaluated a single dose. Seven of eight trials demonstrated superior efficacy of single doses of NSAID compared with placebo. Only four of 13 studies reported increased efficacy of one NSAID compared with another; four other studies found that one NSAID had fewer side effects than one or more others. Thirteen of 14 studies found no difference, or minimal clinical difference, when comparing an NSAID plus opioid combination versus either drug alone. Comparisons between various NSAID plus opioid combinations were inconclusive. Four studies demonstrated increased efficacy with increased NSAID dose, without dose-dependent increases in side effects.

Conclusion

Heterogeneity of study methods and outcomes precluded meta-analyses. Short duration of studies undermines generalization of findings on efficacy and safety. On the basis of limited data, NSAIDs appear to be more effective than placebo for cancer pain; clear evidence to support superior safety or efficacy of one NSAID compared with another is lacking; and trials of combinations of an NSAID with an opioid have disclosed either no significant difference, or at most a slight but statistically significant advantage, compared with either single entity.

Synergistic effects between codeine and diclofenac after local, spinal and systemic administration

This study was designed to evaluate the extent of the antinociceptive interaction between codeine and diclofenac at the local, spinal and systemic level. The effects of individual and fixed-ratio combinations of locally, spinally or orally given codeine and diclofenac were assayed using the formalin test in rats. Isobolographic analysis was employed to characterize the synergism produced by the combinations. Codeine, diclofenac and fixed-ratio codeine-diclofenac combinations produced a dose-dependent antinociceptive effect when administered locally, spinally or systemically. ED(30) values were estimated for the individual drugs and isobolograms were constructed. Theoretical ED(30) values for the combination estimated from the isobolograms were 422.2+/-50.5 microg/paw, 138.5+/-9.2 microg/rat, and 9.3+/-1.1 mg/kg for the local, spinal and oral routes, respectively. These values were significantly higher than the actually observed ED(30) values which were 211.1+/-13.6 microg/paw, 45.9+/-3.9 microg/rat, and 2.5+/-0.2 mg/kg, indicating a synergistic interaction. Systemic administration resulted in the highest increase in potency, being about fourfold, while spinal and local administration increased potency in two- and threefold, respectively. The fact that the highest synergism was observed after systemic administration suggests that the interaction is occurring at several anatomical sites. The results support the clinical use of this combination in pain management.

Double-blind evaluation of short-term analgesic efficacy of orally administered dexketoprofen trometamol and ketorolac in bone cancer pain

The analgesic efficacy and safety of dexketoprofen trometamol (the active enantiomer of the racemic compound ketoprofen) (25mg q.i.d.) vs. ketorolac (10mg q.i.d.) was assessed in 115 patients with bone cancer pain included in a multicenter, randomized, double-blind, parallel group study. A level of >/=40 mm on the 100 mm visual analog scale (VAS) and >/=10 in the pain rating index were required for inclusion. At the end of treatment on day 7 (+1 day), mean values of VAS were 32+/-24 mm for dexketoprofen and 40+/-30 mm for ketorolac (P=0.12) but the pain rating index was significantly lower in patients given dexketoprofen (8.5+/-2.3 vs. 9.7+/-2.9, P=0.04). Moreover, most of the patients reached a pain intensity difference from baseline >/=20 mm (75% of patients for dexketoprofen and 65% of patients for ketorolac). Around half of patients in both treatments had a pain intensity <30 mm on VAS at the end of treatment (55% for dexketoprofen and 47% for ketorolac). In the overall assessment of efficacy, a higher percentage of both patients and physicians rated dexketoprofen as 'quite effective' or 'very effective' compared to ketorolac. The percentage of patients withdrawn from the study for any reason as well as for insufficient therapeutic effect or due to adverse events was lower in the dexketoprofen group than in the ketorolac group. Treatment-related adverse events occurred in 16% of patients given dexketoprofen and in 24% given ketorolac. Serious adverse events occurred in 3.5% of patients from both groups but only one case of gastrointestinal hemorrhage was considered related to ketorolac. We conclude that dexketoprofen trometamol 25 mg q.i.d. oral route is a good analgesic therapy in the treatment of bone cancer pain, comparable to ketorolac 10 mg q.i.d., with a good tolerability profile.

Oral morphine for cancer pain

BACKGROUND

Morphine has been used to relieve pain for many years. Oral morphine in either immediate release or sustained release form remains the analgesic of choice for moderate or severe cancer pain.

OBJECTIVES

To determine the efficacy of oral morphine in relieving cancer pain. To assess the incidence and severity of adverse effects.

SEARCH STRATEGY

The following databases were searched: The Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Library, Issue 4, 2002; the trials register of the Cochrane Pain, Palliative and Supportive Care group (February 2002); MEDLINE 1966 to December 2002; EMBASE 1988 to December 2002; and the Oxford Pain Relief database 1950 to 1994.

SELECTION CRITERIA

Published randomised controlled trials (full reports) reporting on the analgesic effect of oral morphine in adults and children with cancer pain. Any comparator trials were considered. Trials with fewer than 10 subjects were excluded.

DATA COLLECTION AND ANALYSIS

One reviewer extracted data, and the findings were checked by two other reviewers. There were insufficient comparable data for meta-analysis to be undertaken, or to produce numbers-needed-to-treat (NNT) for the analgesic effect.

MAIN RESULTS

Forty five studies (3061 subjects) met the inclusion criteria. Fourteen studies compared oral sustained release morphine (MSR) preparations with immediate release morphine (MIR). Eight studies compared MSR and MSR in different strengths. Nine studies compared MSR with other opioids. Five studies compared MIR with other opioids. Two studies compared oral MSR with rectal MSR. One study was found comparing each of the following: MSR tablet with MSR suspension; MSR with MSR at different dose frequencies; MSR with non-opioids; MIR with non-opioids; oral morphine with epidural morphine; and MIR with MIR by a different route of administration. Morphine was shown to be an effective analgesic. Pain relief did not differ between MSR and MIR. Sustained release versions of morphine were effective for 12 or 24 hour dosing depending on the formulation. Adverse effects were common but only 4% of patients discontinued treatment because of intolerable adverse effects.

REVIEWER'S CONCLUSIONS

The randomised trial literature for morphine is small given the importance of this medicine. Most trials recruited fewer than 100 participants, and did not provide appropriate data for meta-analysis. Trial design was frequently based on titration of morphine or comparator to achieve adequate analgesia, then crossing subjects over in crossover design studies. It is not clear if these trials are sufficiently powered to detect any clinical differences between formulations or comparator drugs.

Drug combinations in pain treatment: a review of the published evidence and a method for finding the optimal combination

The evidence of the usefulness of drug combinations in pain management is reviewed and the problem of finding the optimal combination is presented. For post-operative pain, adding a non-steroidal anti-inflammatory drug (NSAID) or paracetamol to intravenous morphine is beneficial. Adding ketamine to intravenous morphine may be advantageous, but ketamine has a narrow therapeutic window. The combination paracetamol-NSAID is probably superior to either component alone. For post-operative epidural analgesia, combinations of low doses of a local anaesthetic, an opioid and adrenaline (epinephrine) are superior to single-drug regimens. There are virtually no data on the advantages of combinations over single drugs in neuropathic and chronic musculoskeletal pain. Adding NSAIDs or ketamine to opioids may be useful in cancer pain. Because of the enormous number of possible combinations, randomized controlled trials may fail to test the optimal combination. A stepwise optimization model that has been applied in clinical investigations is presented.

Facilitation of enkephalins catabolism inhibitor-induced antinociception by drugs classically used in pain management

The aim of this study was to investigate the facilitatory effects of subanalgesic or low doses of different drugs (acetylsalicylic acid, ibuprofen and morphine) on the antinociceptive responses induced by the endogenous opioid peptides, enkephalins, protected from their catabolism by the dual enkephalin-degrading enzymes inhibitor RB101. According to the analgesic profile of the three studied compounds different antinociceptive assays were used: the hot plate and formalin tests in mice, and the tail flick and paw pressure tests on inflamed paws in rats and polyarthritic rats. Facilitatory effects of subanalgesic doses of acetylsalicylic acid and ibuprofen on RB101-induced antinociceptive responses were observed in the early and late phases of the formalin test, respectively. In the hot plate, tail flick and paw pressure tests, the dose-dependent analgesic effects of RB101 were strongly potentiated by subanalgesic doses of morphine (0.5 mg/kg), while in these tests, acetylsalicylic acid and ibuprofen were unable to modify the RB101-induced antinociceptive responses. The synergism in antinociceptive effects observed with the combination of RB101 and morphine supported by isobolographic analysis, may have interesting clinical implications, considering both the lack of opiate drawbacks observed with RB101 and the high potentiation of its antinociceptive effects with very low doses of morphine.

Strategies to manage the adverse effects of oral morphine: an evidence-based report

Successful pain management with opioids requires that adequate analgesia be achieved without excessive adverse effects. By these criteria, a substantial minority of patients treated with oral morphine (10% to 30%) do not have a successful outcome because of (1) excessive adverse effects, (2) inadequate analgesia, or (3) a combination of both excessive adverse effects along with inadequate analgesia. The management of excessive adverse effects remains a major clinical challenge. Multiple approaches have been described to address this problem. The clinical challenge of selecting the best option is enhanced by the lack of definitive, evidence-based comparative data. Indeed, this aspect of opioid therapeutics has become a focus of substantial controversy. This study presents evidence-based recommendations for clinical-practice formulated by an Expert Working Group of the European Association of Palliative Care (EAPC) Research NETWORK: These recommendations highlight the need for careful evaluation to distinguish between morphine adverse effects from comorbidity, dehydration, or drug interactions, and initial consideration of dose reduction (possibly by the addition of a co analgesic). If side effects persist, the clinician should consider options of symptomatic management of the adverse effect, opioid rotation, or switching route of systemic administration. The approaches are described and guidelines are provided to aid in selecting between therapeutic options.

The use of anti-inflammatory drugs in cancer pain

The role of non-steroidal anti-inflammatory drugs (NSAIDs) in cancer pain has been well established in the treatment of mild pain and also alone or in association with opioids for the treatment of moderate to severe pain. Acutely, NSAIDs may be more than mild analgesics, and may provide additional analgesia when combined with opioids. However, NSAIDs have ceiling effects and there is no therapeutic gain from increasing dosages beyond those recommended. As there is no clearly superior NSAID, the choice should be based on experience and the toxicity profile that probably relates to the COX-1:COX-2 ratio. Among the older drugs, ibuprofen seems to have these properties.Non-steroidal anti-inflammatory drugs have been shown to have an opioid-sparing effect. Although the value of a simple narcotic-sparing effect may be questioned in cancer pain treatment, the use of NSAIDs may be useful when the increase in opioid dosage determine the occurrence of opioid toxicity. Like opioids, NSAIDs should not be considered analgesics for a specific type or cause of pain. There is a lack of evidence for any difference between different routes of NSAIDs administration. The long-term toxicity of NSAIDs in cancer pain is poorly defined due to a lack of studies. A variety of strategies have been used in an attempt to reduce the risks associated with NSAID therapy. Those NSAIDs that are weak COX-1 inhibitors may be preferred. In addition, concomitant administration of misoprostol is recommended in patients at increased risk for upper gastrointestinal complications.

Psychotropic adjuvant analgesics for pain in cancer and AIDS

The 'WHO Analgesic Ladder' is a well validated approach for the selection of appropriate analgesic therapy for cancer pain as well as pain in AIDS. The mainstay of analgesic intervention for cancer and AIDS pain of moderate to severe intensity continues to be the appropriate use of opioid analgesics. There is, however, a growing appreciation for the role of adjuvant analgesics, such as antidepressants and other psychotropic medications, at each step of the WHO Analgesic Ladder, particularly in the treatment of neuropathic pain. Knowledge of the indications and usefulness of psychotropic analgesic drugs in cancer and AIDS pain populations will be most important to clinicians practicing in psycho-oncology/AIDS settings, particularly since these drugs are useful not only in the treatment of psychiatric complications of cancer and AIDS, but also as adjuvant analgesic agents in the management of pain. This paper reviews the literature on the use of antidepressants, psychostimulants, neuroleptics, anticonvulsants and other psychotropic analgesics in the management of cancer and AIDS pain. Mechanisms of analgesia, drug selection, and recommendations for clinical usage are discussed. The appropriate and timely use of psychotropic adjuvant analgesic drugs represents an opportunity for active psychiatric contribution to the multidisciplinary management of cancer and AIDS pain.