Validated medication deprescribing instruments for patients with palliative care needs palliative care: A systematic review

OBJECTIVES

Patients with life-limiting illnesses are prone to unnecessary polypharmacy. Deprescribing tools may contribute to minimizing negative outcomes. Thus, the aims of the study were to identify validated instruments for deprescribing inappropriate medications for patients with palliative care needs and to assess the impact on clinical, humanistic, and economic outcomes.

METHODS

A systematic review was conducted in LILACS, PUBMED, EMBASE, COCHRANE, and WEB OF SCIENCE databases (until May 2021). A manual search was performed in the references of enrolled articles. The screening, eligibility, extraction, and bias risk assessment were carried out by two independent researchers. Experimental and observational studies were eligible for inclusion.

RESULTS

Out of the 5,791 studies retrieved, after excluding duplicates (n = 1,050), conducting title/abstract screening (n = 4,741), and full reading (n = 41), only one study met the inclusion criteria. In this included study, a randomized controlled trial was conducted, which showed a high level of bias risk overall. Adults 75 years or older (n = 130) with limited life expectancy and polypharmacy were allocated to two groups [intervention arm (deprescribing); and control arm (usual care)]. Deprescribing was performed with the aid of the STOPPFrail tool. The mean number of inappropriate medications and monthly medication costs were significantly lower in the intervention arm. No statistically significant differences were found in terms of unscheduled hospital presentations, falls, fractures, mortality, and quality of life.

CONCLUSIONS

Despite the availability of several instruments to support deprescribing in patients with palliative care needs, only one of them has undergone validation and robust assessment for effectiveness in clinical practice. The STOPPFrail tool appears to reduce the number of inappropriate medications for older people with limited life expectancy (and probably palliative care needs) and decrease the monthly costs of pharmacotherapy. Nevertheless, the impact on patient safety and humanistic outcomes remain unclear.

Validated medication deprescribing instruments for patients with palliative care needs: a systematic review

OBJECTIVES

Patients with life-limiting illnesses are prone to unnecessary polypharmacy. Deprescribing tools may contribute to minimizing negative outcomes. Thus, the aims of the study were to identify validated instruments for deprescribing inappropriate medications for patients with palliative care needs and to assess the impact on clinical, humanistic, and economic outcomes.

METHODS

A systematic review was conducted in LILACS, PUBMED, EMBASE, COCHRANE, and WEB OF SCIENCE databases (until May 2021). A manual search was performed in the references of enrolled articles. The screening, eligibility, extraction, and bias risk assessment were carried out by 2 independent researchers. Experimental and observational studies were eligible for inclusion.

RESULTS

Out of the 5791 studies retrieved, after excluding duplicates (n = 1050), conducting title/abstract screening (n = 4741), and full reading (n = 41), only 1 study met the inclusion criteria. In this included study, a randomized controlled trial was conducted, which showed a high level of bias risk overall. Adults 75 years or older (n = 130) with limited life expectancy and polypharmacy were allocated to 2 groups [intervention arm (deprescribing); and control arm (usual care)]. Deprescribing was performed with the aid of the STOPPFrail tool. The mean number of inappropriate medications and monthly medication costs were significantly lower in the intervention arm. No statistically significant differences were found in terms of unscheduled hospital presentations, falls, fractures, mortality, and quality of life.

CONCLUSIONS

Despite the availability of several instruments to support deprescribing in patients with palliative care needs, only 1 of them has undergone validation and robust assessment for effectiveness in clinical practice. The STOPPFrail tool appears to reduce the number of inappropriate medications for older people with limited life expectancy (and probably palliative care needs) and decrease the monthly costs of pharmacotherapy. Nevertheless, the impact on patient safety and humanistic outcomes remain unclear.

A cholinergic circuit that relieves pain despite opioid tolerance

Chronic pain is a tremendous burden for afflicted individuals and society. Although opioids effectively relieve pain, significant adverse outcomes limit their utility and efficacy. To investigate alternate pain control mechanisms, we explored cholinergic signaling in the ventrolateral periaqueductal gray (vlPAG), a critical nexus for descending pain modulation. Biosensor assays revealed that pain states decreased acetylcholine release in vlPAG. Activation of cholinergic projections from the pedunculopontine tegmentum to vlPAG relieved pain, even in opioid-tolerant conditions, through ⍺7 nicotinic acetylcholine receptors (nAChRs). Activating ⍺7 nAChRs with agonists or stimulating endogenous acetylcholine inhibited vlPAG neuronal activity through Ca2+ and peroxisome proliferator-activated receptor α (PPAR⍺)-dependent signaling. In vivo 2-photon imaging revealed that chronic pain induces aberrant excitability of vlPAG neuronal ensembles and that ⍺7 nAChR-mediated inhibition of these cells relieves pain, even after opioid tolerance. Finally, pain relief through these cholinergic mechanisms was not associated with tolerance, reward, or withdrawal symptoms, highlighting its potential clinical relevance.

Intercostal Cryo Nerve Block in Minimally Invasive Cardiac Surgery: The Prospective Randomized FROST Trial

INTRODUCTION

Intercostal cryo nerve block has been shown to enhance pulmonary function recovery and pain management in post-thoracotomy procedures. However, its benefit have never been demonstrated in minimal invasive thoracotomy heart valve surgery (Mini-HVS). The purpose of the study was to determine whether intraoperative intercostal cryo nerve block in conjunction with standard of care (collectively referred to hereafter as CryoNB) provided superior analgesic efficacy in patients undergoing Mini-HVS compared to standard-of-care (SOC).

METHODS

FROST was a prospective, 3:1 randomized (CryoNB vs. SOC), multicenter trial in patients undergoing Mini-HVS. The primary endpoint was the 48-h postoperative forced expiratory volume in 1 s (FEV1) result. Secondary endpoints were visual analog scale (VAS) scores for pain at the surgical site and general pain, intensive care unit and hospital length-of-stay, total opioid consumption, and allodynia at 6 months postoperatively.

RESULTS

A total of 84 patients were randomized to the two arms of the trial CryoNB (n = 65) and SOC (n = 19). Baseline Society of Thoracic Surgeons Predictive Risk of Mortality (STS PROM) score, ejection fraction, and FEV1 were similar between cohorts. A higher 48-h postoperative FEV1 result was demonstrated in the CryoNB cohort versus the SOC cohort (1.20 ± 0.46 vs. 0.93 ± 0.43 L; P = 0.02, one-sided two-sample t test). Surgical site VAS scores were similar between the CryoNB and SOC cohorts at all postoperative timepoints evaluated, but VAS scores not related to the surgical site were lower in the SOC group at 72, 94, and 120 h postoperatively. The SOC cohort had a 13% higher opioid consumption than the CryoNB cohort. One of 64 CryoNB patients reported allodynia that did not require pain medication at 10 months.

CONCLUSIONS

The results of FROST demonstrated that intercostal CryoNB provided enhanced FEV1 score at 48 h postoperatively with optimized analgesic effectiveness versus SOC. Future larger prospective randomized trials are warranted to determine whether intercostal CryoNB has an opioid-sparing effect in patients undergoing Mini-HVS.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02922153.

Predictors, rates, and trends of opioid use disorder among patients hospitalized with chronic pancreatitis

Background

Patients with chronic pancreatitis (CP) suffer from pain and receive increased opioid prescriptions with a high risk of opioid use disorder (OUD). We studied the predictors, trends and outcomes of OUD among patients hospitalized with CP.

Methods

Records with CP (with/without OUD) were extracted from the Nationwide Inpatient Sample (NIS) 2012-2014, and the association of OUD with the burden of CP was calculated. We then charted the trends of OUD and its interaction with concomitant CP from NIS 2007-2014 (SAS 9.4).

Results

In the period 2012-2014, 4349 (4.99%) of the 87,068 CP patients had concomitant OUD, with higher risk among patients who were young, females, white vs. Hispanics, and individuals with chronic back pain, arthritis, non-opioid substance use, mental health disorders, and those hospitalized in urban centers. OUD was associated with a longer hospital stay (6.9 vs. 6.5 days, P=0.0015) but no significant difference in charges ($47,151 vs. $49,017, P=0.0598) or mortality (1.64% vs. 0.74%, P=0.0506). From 2007-2014, the average yearly rate of OUD was 174 cases per 10,000 hospitalizations (174/10,000), almost 3 times higher among CP vs. non-CP (479/10,000 vs. 173/10,000, P<0.001), and it increased from 2007 to 2014 (135/10,000 to 216/10,000, P<0.001). The yearly increase was 2.7 times higher among patients with CP vs. non-CP (29.9/10,000 vs. 11.3/10,000 hospitalizations/year, P<0.001).

Conclusions

CP is associated with higher rates and trends of OUD. Patients with CP at high risk of OUD may benefit from alternate analgesic regimens or surveillance for OUD when they are prescribed opioids.

Long-term Opioids Linked to Hypogonadism and the Role of Testosterone Supplementation Therapy

Opioids play a pivotal role in managing chronic pain with increasing prescription rates over the last few years. Hence, it is crucial to focus on the adverse effects of narcotics, and one of the lesser-known side effects is hypogonadism. Opioids act on the hypothalamus, pituitary, and directly on the gonads affecting serum testosterone levels. Narcotic-induced androgen insufficiency contributes to sexual dysfunction, infertility, hyperalgesia, and involving various body functions overall, affecting the quality of life. Opioid-induced hypogonadism is very challenging to diagnose for the clinicians, as the patients often under-report the symptoms. There are no established guidelines to analyze androgen insufficiency and dealing with their manifestations successfully. We did a substantial search in PubMed and Google Scholar, using various combinations of keywords to collect data to evaluate the impacts of opioids on serum testosterone levels. This study aims to highlight the clinical significance of opioid-induced androgen deficiency and the diagnostic techniques to recognize and credible treatment alternatives, including testosterone replacement therapy. Health care providers should screen the patients routinely for the signs and symptoms and monitor them often for the hormonal changes to select the patients cautiously for testosterone replacement therapy.

Healthcare professionals' perceptions on the use of opioid analgesics for the treatment of cancer-related pain in Cyprus: A mixed-method study

OBJECTIVES

Pain is considered the most common and debilitating symptom reported by patients affected by cancer, and opioids are at the front line for its effective management. However, the appropriate use of opioids can be limited by healthcare professionals' perceptions on opioids. Therefore, the aim of this study was to explore their perceptions on the use of opioids medication.

METHODS

This was a study of sequential mixed-method design conducted in Cyprus. As part of the quantitative phase of the study, the Barriers to Opioid Analgesic Availability Test questionnaire was completed by 73 physicians randomly selected. In the qualitative phase, 28 healthcare professionals working in primary and secondary healthcare centers participated in two focus groups. They were asked to express their perceptions on the use of opioid analgesics for the treatment of cancer-related pain. Data were analyzed according to Colaizzis' seven-stage phenomenological analysis.

RESULTS

The quantitative analysis showed that 69.85% of physicians acknowledge opiophobia as a main barrier to appropriate pain relief but also explicitly for cancer pain which is not adequately managed (45.19%). In terms of opioids availability, physicians stated that moderate to severe problems in opioids availability were mainly caused by their reluctance to prescribe opioids (49.3%) followed by the laws/regulations in place (41.08%). The qualitative analysis yielded the following six main themes: inadequate training of healthcare professionals in the use of opioid analgesics, inadequate patient/caregivers' awareness of opioid analgesics, opiophobia in healthcare professionals, opiophobia of patients/caregivers, poor management of opioid analgesics by healthcare professionals and patients/caregivers, and ineffective pain relief with opioids.

CONCLUSIONS

The lack of appropriate education is a significant barrier to opioids use in Cyprus. This is compounded by the attitudes and phobias of both healthcare professionals and the general public. In addition, there are barriers to opioid availability and unsatisfactory cancer pain relief.

Guidelines for prescribing opioids for chronic non-cancer pain in Korea

As the treatment of chronic non-cancer pain gradually increases, clinicians have more opportunities to encounter opioid prescription. However, guidelines for prescribing opioids for chronic non-cancer pain have never been published in Korea. The present guidelines were prepared by reviewing various research data. In cases in which the data were insufficient, recommendations were presented following discussion among experts affiliated with the Opioids Research Group in the Korean Pain Society. The present guidelines may need to be continuously revised and amended as more clinical evidence is acquired.

Retrospective Evaluation of a Fixed-Dose Combination of Oxycodone and Acetaminophen to Manage Moderate Pain: The Lower the Better

INTRODUCTION

Oxycodone is one of the most commonly used opioid analgesics in the clinical management of pain. The present retrospective analysis aimed to determine the dose of oxycodone that could achieve effective control of moderate pain when combined with a fixed dose of acetaminophen, and the time required to reach a clinically relevant reduction in intensity of pain.

METHODS

Data of patients treated with a combination of oxycodone (5, 10, and 20 mg) and acetaminophen (325 mg) were evaluated for gender, current disease condition, basal pain intensity, total daily dose, days of controlled pain at the initial low dose, and pain intensity after treatment using a numeric pain rating scale.

RESULTS

Data from a total of 491 patients were assessed; of these 93.5% of patients experienced persistent non-cancer pain and had an average baseline pain score of 5.68 ± 1.35. For the overall population, the pain score was reduced to 2.49 ± 1.71 with a mean dose of 8.68 ± 4.96 mg oxycodone after 21.60 ± 6.12 days of treatment with the combination. Almost 97% of the patients who reported relief of pain received 1.61 ± 0.67 doses of oxycodone 5 mg combined with 325 mg of acetaminophen.

CONCLUSION

A low-dose combination of oxycodone with acetaminophen can be effective in the management of moderate pain and may help in reducing the treatment-associated adverse reactions and drug dependence.

FUNDING

Sponsorship for article processing charges was provided by Molteni Farmaceutici, Florence, Italy.

To predict sufentanil requirement for postoperative pain control using a real-time method: A prospective observational cohort study

Preoperative identification of individual sensitivity to opioid analgesics could improve the quality of postoperative analgesia. We explored the feasibility and utility of a real-time assessment of sufentanil sensitivity in predicting postoperative analgesic requirement.Our primary study included 111 patients who underwent measurements of pressure and quantitative pricking pain thresholds before and 5 minutes after sufentanil infusion. Pain intensity was assessed during the first 24-hour postsurgery, and patients who reported inadequate levels of analgesia were excluded from the study. The sufentanil requirement for patient-controlled analgesia was recorded, and a subsequent exploratory study of 20 patients facilitated the interpretation of the primary study results. In the primary study, experimental pain thresholds increased (P < 0.001) 5 minutes after sufentanil infusion, and the percent change in pricking pain threshold was positively associated with sufentanil requirement at 12 and 24 hours after surgery (β = 0.318, P = 0.001; and β = 0.335, P = 0.001). A receiver-operating characteristic curve analysis showed that patients with a change in pricking pain threshold >188% were >50% likely to require more sufentanil for postoperative pain control. In the exploratory study, experimental pain thresholds significantly decreased after the operation (P < 0.001), and we observed a positive correlation (P < 0.001) between the percent change in pricking pain threshold before and after surgery. Preoperative detection of individual sensitivity to sufentanil via the above described real-time method was effective in predicting postoperative sufentanil requirement. Thus, percent change in pricking pain threshold might be a feasible predictive marker of postoperative analgesia requirement.

Effective Dose Titration of Fentanyl Sublingual Spray in Patients With Breakthrough Cancer Pain

OBJECTIVE

To further describe effective dose titration of fentanyl sublingual spray to treat breakthrough cancer pain (BTCP) during the 26-day open-label titration phase of a phase 3, randomized, double-blind, placebo-controlled study.

METHODS

Opioid-tolerant patients with 1 to 4 episodes of BTCP per day were enrolled. For randomization into double-blind treatment, patients must have titrated to a dose (100 to 1,600 mcg) providing effective analgesia for 2 consecutive BTCP episodes. The Treatment Satisfaction Questionnaire for Medication was administered at baseline and at titration end and included a Global Satisfaction domain.

RESULTS

Of 130 patients undergoing titration, 98 (75%) achieved pain relief (median dose = 800 mcg). The most common doses that allowed for adequate pain relief were 800 mcg (24.5%) and 1,200 mcg (20.4%). Of 32 (25%) patients who withdrew from the study, only 3 (2.3%) did not achieve an effective dose. In patients attaining an effective dose, mean Global Satisfaction increased from 54.9 ± 2.1 at baseline to 75.3 ± 1.7 at the end of the titration phase. Seventy-eight patients (60%) reported ≥ 1 adverse event (AE). Thirty-three AEs (25.4%) were considered probably related to treatment, with nausea (6.2%) and somnolence (4.6%) most commonly reported.

CONCLUSIONS

In patients with BTCP, fentanyl sublingual spray can be rapidly and safely titrated to an effective dose, resulting in greater satisfaction with fentanyl sublingual spray than previous BTCP medications.

A new real-time method for detecting the effect of fentanyl using the preoperative pressure pain threshold and Narcotrend index: a randomized study in female surgery patients

Individual variability in the effects of opioid analgesics such as fentanyl remains a major challenge for tailored pharmacological treatment including postoperative analgesia. This study aimed to establish a new real-time method for detecting the effects of fentanyl and their individual differences in the preoperative period, using the pressure pain threshold (PPT) and Narcotrend index (NTI) test.Eighty women undergoing elective surgery under general anesthesia were enrolled in this randomized, double-blinded, placebo-controlled study to receive either intravenous fentanyl (Group F) or saline (Group S). Before (T1) and 5 (T2) and 10 min (T3) after intravenous injection, the PPT, NTI, respiratory rate, heart rate, blood pressure, and pulse oxygen saturation were measured. The initial time at which the Narcotrend index showed a decline was also recorded.In total, 40 patients in Group S and 38 patients in Group F were included in the final analysis. At 5 min and 10 min after intravenous fentanyl administration, the analgesic effect was determined by measuring the PPT, which was significantly increased (P < 0.001), and the sedative effect was detected using the NTI, which was significantly decreased (P < 0.001). The distribution of percentage changes of the PPT and NTI showed individual differences. At T2 and T3, the absolute changes in NTI and PPT were positively correlated (r = 0.444 at T2, P = 0.005; r = 0.332 at T3, P = 0.042).Through the PPT and NTI, it was feasible to easily detect the effects of fentanyl and their individual differences in real time before induction of anesthesia in the operation room. This method could potentially be applied to preoperatively determine patients' sensitivity to fentanyl.

Evidence-Based Guidelines on the Use of Opioids in Chronic Non-Cancer Pain—A Consensus Statement by the Pain Association of Singapore Task Force

Introduction: While opioids are effective in carefully selected patients with chronic non-cancer pain (CNCP), they are associated with potential risks. Therefore, treatment recommendations for the safe and effective use of opioids in this patient population are needed. Materials and Methods: A multidisciplinary expert panel was convened by the Pain Association of Singapore to develop practical evidence-based recommendations on the use of opioids in the management of CNCP in the local population. This article discusses specific recommendations for various common CNCP conditions. Results: Available data demonstrate weak evidence for the long-term use of opioids. There is moderate evidence for the short-term benefit of opioids in certain CNCP conditions. Patients should be carefully screened and assessed prior to starting opioids. An opioid treatment agreement must be established, and urine drug testing may form part of this agreement. A trial duration of up to 2 months is necessary to determine efficacy, not only in terms of pain relief, but also to document improvement in function and quality of life. Regular reviews are essential with appropriate dose adjustments, if necessary, and routine assessment of analgesic efficacy, aberrant behaviour and adverse effects. The reasons for discontinuation of opioid therapy include side effects, lack of efficacy and aberrant drug behaviour. Conclusion: Due to insufficient evidence, the task force does not recommend the use of opioids as first-line treatment for various CNCP. They can be used as second- or third-line treatment, preferably as part of a multimodal approach. Additional studies conducted over extended periods are required. Key words: Chronic pain, Consensus statement, Guidelines, Non-cancer pain, Opioids

Disaster after the plaster. Fentanyl withdrawal symptoms in a curable hospice patient

Opioids have been used for thousands of years for pain relief. Transdermal fentanyl (TDF) is a synthetic opioid that is prescribed for the treatment of chronic pain. This clinical lesson demonstrates that TDF may be easy to start but sometimes difficult to stop. Like any other opioid there is a substantial risk of physical dependence and subsequent withdrawal symptoms after discontinuation of the drug. Here, we present a case of a hospice patient who developed withdrawal symptoms after a first TDF tapering attempt according to the manufacturer's instructions. A second, more gradual tapering regimen did not result in withdrawal symptoms. The mechanisms and treatment modalities for physical dependence along with a tailor-made tapering strategy that is suitable for general practice are presented in this clinical lesson.

Long-term effectiveness and tolerability of sublingual fentanyl orally disintegrating tablet for the treatment of breakthrough cancer pain

BACKGROUND AND OBJECTIVES

Breakthrough cancer pain (BTcP) is a transient exacerbation of cancer pain in patients with otherwise stable, persistent background pain. This study evaluated the long-term effectiveness and tolerability of sublingual fentanyl orally disintegrating tablet (sublingual fentanyl ODT), for the treatment of BTcP in opioid-tolerant patients with cancer.

RESEARCH DESIGN AND METHODS

This was a non-randomized, open-label, multi-center, Phase III study conducted in opioid-tolerant patients (aged ≥17 years) with BTcP. The study comprised a 2-week titration phase, followed by a maintenance phase of up to 12 months. Patients self-administered sublingual fentanyl ODT for episodes of BTcP. Effectiveness was assessed using patients' global evaluation of medication (PGEM), the brief pain inventory (BPI) and the depression, anxiety and positive outlook scale (DAPOS). Adverse events were recorded throughout.

CLINICAL TRIAL REGISTRATION

NCT00263575 (http://www.clinicaltrials.gov/).

RESULTS

Of 139 recruited patients, 69% identified an effective dose of sublingual fentanyl ODT (a dosage that successfully treated all episodes of BTcP over two consecutive days) and entered the maintenance phase, during which they were treated for a median of 149.0 days (mean dose 507.5 µg). The study recorded a significant increase in reported satisfaction with pain medication at the 6-month and end-of-study visits, compared to screening (p ≤ 0.01). Evaluation of quality of life using BPI and DAPOS identified no deterioration in scores and significant improvements in certain parameters (p < 0.05). Sublingual fentanyl ODT was well tolerated, with no study drug-related deaths, and 49 patients (35.3%) experiencing ≥1 study drug-related adverse event. The most common of these included nausea (8.6%), constipation (5.8%) and somnolence (5.8%). There was no evidence of sublingual mucosal irritation due to the study medication. The pattern of adverse events was similar to that previously observed with transmucosal fentanyl.

CONCLUSIONS

Sublingual fentanyl ODT was effective and well tolerated for the long-term treatment of BTcP in opioid-tolerant cancer patients. There was an increase in satisfaction with pain medication during the study, and sublingual fentanyl ODT showed an acceptable safety profile over 12 months of treatment.

Opioids: a two-faced Janus

BACKGROUND

Long-term pain is a debilitating condition that is costly to treat and has a significant impact on patient quality of life. Classical opioids have been used for the treatment of pain for centuries and are one of the most effective drug classes available for acute severe pain and long-term pain. However, concerns regarding adverse effects, tolerance to analgesic effects and the potential for addiction have resulted in a reluctance to prescribe and use opioids for the management of long-term non-cancer pain. Adverse events, including gastrointestinal side effects such as constipation, nausea and vomiting, and central nervous system side effects such as sedation are responsible for as many as one in five patients discontinuing opioid treatment, often leading to inadequate pain relief and poor patient quality of life. Therefore, new analgesic therapies are needed that are associated with fewer adverse effects, whilst providing sustainable pain relief for patients with long-term pain.

OBJECTIVE AND METHODS

To provide an overview of the historical development, uses, mechanisms of action, receptor affinities and side-effect profiles of classical opioids. In addition, recent developments and novel approaches for long-term, severe pain treatment are also reviewed.

RESULTS

A number of treatment strategies were identified: co-administration with opioid-sparing analgesics to reduce side effects and/or risk of dependence, the use of peripheral opioid antagonists and novel delivery mechanisms to reduce side effects, the development of non-opioid agents that reduce side effects and enhance analgesia such as glial cell modulators, and the development of novel agents with combined µ-receptor and monoaminergic activity within the same molecule.

CONCLUSIONS

Despite these recent advances, there have been very few completely novel drug developments. Hence, there remains a continuing need for innovative therapeutic strategies for the treatment of long-term pain. The most promising alternatives appear to be the use of traditional opioids together with peripheral opioid antagonists, combining opioids with glial cell modulators, and the use of novel agents with µ-receptor agonist and noradrenaline reuptake inhibitor activity within the same molecule (MOR-NRI compounds).

Effects of opioid rotation in chronic pain patients: ORTIBARN study

BACKGROUND

Opioid rotation is currently the subject of considerable debate for two reasons: firstly as a strategy for pain treatment, and secondly because of the difficulty in determining equianalgesic doses. Switching from one slow-release (SR) opioid analgesic to another raises a number of critical issues, and there are no widespread studies that support a standard protocol. Initiation of opioid therapy must consider gradual dose titration of the drug until the minimum effective and maximum tolerated dosage for each patient is found.

OBJECTIVE

This study aimed to evaluate the effects of SR opioid rotation after a stabilization period with normal-release (NR) morphine ('start therapy') in patients with cancer or non-cancer pain not controlled with their current SR opioid.

METHODS

This is a multicentre, open-label, prospective study. A total of 326 consecutive patients were enrolled who were affected by chronic cancer or non-cancer pain that was not controlled by an SR opioid administered as either monotherapy or in combination with other analgesic drugs. Following start therapy with oral NR morphine at a dosage of 5 mg or 10 mg every 4 hours, rotation to an SR opioid of a different type from that previously administered was carried out.

RESULTS

After about 3 days of start therapy with NR morphine, rotation to an SR opioid allowed a significant decrease of both baseline pain and daily episodes of breakthrough pain. No significant difference was detected between dosages and type of opioid administered, both prior to and after the start therapy period with NR morphine.

CONCLUSIONS

Rotation to another opioid preceded by a brief period of opioid receptor resetting by start therapy with NR morphine allows a good level of pain control and avoids rotation to inappropriate opioid dosages or combinations analgesics.

Evaluation of N-substitution in 6,7-benzomorphan compounds

6,7-benzomorphan derivatives, exhibiting different mu, delta, and kappa receptor selectivity profiles depending on the N-substituent, represent a useful skeleton for the synthesis of new and better analgesic agents. In this work, an aromatic ring and/or alkyl residues have been used with an N-propanamide or N-acetamide spacer for the synthesis of a new series of 5,9-dimethyl-2'-hydroxy-6,7-benzomorphan derivatives (12-22). Data obtained by competition binding assays showed that the mu opioid receptor seems to prefer an interaction with the 6,7-benzomorphan ligands having an N-substituent with a propanamide spacer and less hindered amide. Highly stringent features are required for delta receptor interaction, while an N-acetamide spacer and/or bulkier amide could preferentially lead to kappa receptor selectivity. In the propanamide series, compound 12 (named LP1) displayed high mu affinity (Ki=0.83 nM), good delta affinity (Ki=29 nM) and low affinity for the kappa receptor (Ki=110 nM), with a selectivity ratio delta/mu and kappa/mu of 35.1 and 132.5, respectively. Further, in the adenylyl cyclase assay, LP1 displayed a mu/delta agonist profile, with IC50 values of 4.8 and 12 nM at the mu and delta receptors, respectively. The antinociceptive potency of LP1 in the tail-flick test after sc administration in rat was comparable with the potency of morphine (ED50=2.03 and 2.7 mg/kg, respectively), and was totally reversed by naloxone. LP1, possessing a mu/delta agonist profile, could represent a lead in further developing benzomorphan-based ligands with potent in vivo analgesic activity and a reduced tendency to induce side effects.

Morphine/naltrexone

Oral morphine/naltrexone extended release capsules comprise the selective mu-opioid receptor agonist morphine in a sustained-release formulation combined with a sequestered core of the mu-opioid receptor antagonist naltrexone for use in the management of moderate to severe pain. When morphine/naltrexone is taken as intended, naltrexone exerts no clinically significant effect. However, when the capsule contents are taken after being tampered with by crushing, chewing or dissolution, naltrexone is rapidly released and absorbed, thereby mitigating the effects of morphine. Morphine/naltrexone was effective in the treatment and management of moderate to severe chronic pain in patients with pain due to osteoarthritis of the hip or knee participating in a randomized, double-blind, placebo-controlled, phase III study (n = 344). Changes in mean Brief Pain Inventory (BPI) average scores from baseline of the double-blind maintenance phase to 12 weeks were significantly better with morphine/naltrexone (20 mg/0.8 mg to 80 mg/3.2 mg twice daily) than with placebo. In a 12-month, open-label safety study, morphine/naltrexone also provided effective pain relief and sustained pain control in patients with chronic, moderate to severe, nonmalignant pain (n = 465 at baseline; 162 at study end). Furthermore, significant mean changes from baseline in BPI worst, least, average and current pain scores were seen from week 1 onwards. Morphine/naltrexone treatment was generally well tolerated in adult patients with chronic moderate to severe nonmalignant pain in clinical trials of up to 1-year duration.

Opioid pharmaceuticals and addiction: the issues, and research directions seeking solutions

There are few pharmaceuticals superior to opiates for the treatment of pain. However, with concerns of addiction, withdrawal and questionable efficacy for all types of pain, these compounds are far from a magical panacea for pain-relief. As it is unlikely that other classes of compounds will supersede the opioids in the very near future, it is important to both optimize current opioid therapies and curb the astounding diversion of opioids from their intended analgesic use to non-medical abuse. In optimizing opioid therapeutics it is necessary to enhance the clinical awareness of the benefits of treating pain and combine this with aggressive strategies to reduce diversion for non-medical use. At the heart of the issue of opioid misuse is the role of opioid systems in the reward circuitry, and the adaptive processes associated with repetitive opioid use that manifest during withdrawal. Emerging pharmacological insights of opioid receptors will be reviewed that provide future hope for developing opioid-based analgesics with reduced addictive properties and perhaps, reduced opponent processes. In addition, with the increased understanding of nociceptive circuitry and the molecules involved in transmitting pain, new therapeutic targets have become evident that may result in effective analgesics either alone or in combination with current opioid therapies.