Opioid switching and rotation in primary care: implementation and clinical utility

Opioid analgesic dose and route conversion ratio studies: a scoping review to inform an eDelphi guideline

BACKGROUND

Clinicians regularly prescribe opioids to manage acute and chronic cancer pain, frequently to address acute postoperative pain, and occasionally to manage chronic non-cancer pain. Clinical efficacy may be suboptimal in some patients due to side effects and/or poor response, and opioid rotation/switching (conversions) is frequently necessary. Despite the widespread practice, opioid conversion ratios are inconsistent between clinicians, practices, and countries. Therefore, we performed a scoping systematic review of opioid conversion studies to inform an international eDelphi guideline.

METHODS

To ensure a comprehensive review, we conducted a systematic search across multiple databases (OVID Medline, PsycINFO, Embase, EBM-Cochrane Database of Systematic Reviews and Registered Trials, LILACS, IMEMR, AIM, WPRIM) using studies published up to June 2022. Additionally, we performed hand and Google Scholar searches to verify the completeness of our findings. Our inclusion criteria encompassed randomized and non-randomized studies with no age limit, with only a few pediatric studies identified. We included studies on cancer, non-cancer, acute, and chronic pain. The level and grade of evidence were determined based on the Multinational Supportive Care in Cancer (MASCC) criteria.

RESULTS

Our search yielded 21,118 abstracts, including 140 randomized (RCT) and 68 non-randomized (NRCT) clinical trials. We compared these results with recently published conversion ratios. Modest correlations were noted between published reviews and the present scoping systematic review.

CONCLUSION

The present scoping systematic review found low-quality evidence to support an opioid conversion guideline. We will use these data, including conversion ratios and type and route of administration, to inform an eDelphi guideline.

Comparison of the Effects of OPRM1 A118G Polymorphism Using Different Opioids: A Prospective Study

CONTEXT

μ-opioid receptor gene (OPRM1) A118G polymorphism (rs1799971) causes loss of N-glycosylation sites at the extracellular domain of μ-opioid receptors. G-allele carriers show a limited response to morphine; however, studies investigating the impact of A118G polymorphism on the efficacy of opioids other than morphine are limited.

OBJECTIVE

To compare the impact of A118G polymorphism on the efficacy of various opioids.

METHODS

This prospective cohort study enrolled 222 in-patients administered one of the following opioid therapies for cancer pain as part of an opioid introduction or rotation strategy: tapentadol extended-release tablets, methadone tablets, hydromorphone controlled-release tablets, oxycodone controlled-release tablets, or transdermal fentanyl patches. The impact of A118G polymorphism on the difference in the Brief Pain Inventory-Short Form score on days three, seven, and 14 from baseline was compared among the groups.

RESULTS

Overall, 81, 74, and 67 patients had the AA, AG, and GG genotypes, respectively, with an OPRM1 A118G G-allele variant frequency of 0.47. The reduction in the Brief Pain Inventory-Short Form score after opioid therapy initiation did not differ significantly among the patients with the three A118G genotypes treated with tapentadol (p = 0.84) or methadone (p = 0.97), whereas it was significantly smaller in G-allele carriers than that in AA homozygous patients treated with hydromorphone (p < 0.001), oxycodone (p = 0.031), or fentanyl (p < 0.001).

CONCLUSION

Tapentadol and methadone may be more suitable than hydromorphone, oxycodone, and fentanyl for G-allele carriers due to their dual mechanism of action and low susceptibility to OPRM1 A118G polymorphism.

Comparative Study of Opioid Initiation With Tramadol, Short-acting Hydrocodone, or Short-acting Oxycodone on Opioid-related Adverse Outcomes Among Chronic Noncancer Pain Patients

OBJECTIVE

To compare the safety profiles of low and high-dose tramadol, short-acting hydrocodone, and short-acting oxycodone therapies among chronic noncancer pain individuals.

MATERIALS AND METHODS

A retrospective cohort study of individuals with back/neck pain/osteoarthritis with an initial opioid prescription for tramadol, hydrocodone, or oxycodone was conducted using IQVIA PharMetrics Plus claims for Academics database (2006 to 2020). Two cohorts were created for separately studying opioid-related adverse events (overdoses, accidents, self-inflicted injuries, and violence-related injuries) and substance use disorders (opioid and nonopioid). Patients were followed from the index date until an outcome event, end of enrollment, or data end. Time-varying exposure groups were constructed and Cox regression models were estimated.

RESULTS

A total of 1,062,167 (tramadol [16.5%], hydrocodone [61.1%], and oxycodone [22.4%]) and 986,809 (tramadol [16.5%], hydrocodone [61.3%], and oxycodone [22.2%]) individuals were in the adverse event and substance use disorder cohorts. All high-dose groups had elevated risk of nearly all outcomes, compared with low-dose hydrocodone. Compared with low-dose hydrocodone, low-dose oxycodone was associated with a higher risk of opioid overdose (hazard ratio: 1.79 [1.37 to 2.33]). No difference in risk was observed between low-dose tramadol and low-dose hydrocodone (hazard ratio: 0.85 [0.64 to 1.13]). Low-dose oxycodone had higher risks of an opioid use disorder, and low-dose tramadol had a lower risk of accidents, self-inflicted injuries, and opioid use disorder compared with low-dose hydrocodone.

DISCUSSION

Low-dose oxycodone had a higher risk of opioid-related adverse outcomes compared with low-dose tramadol and hydrocodone. This should be interpreted in conjunction with the benefits of pain control and functioning associated with oxycodone use in future research.

Ensuring Patient Protections When Tapering Opioids: Consensus Panel Recommendations

Long-term opioid therapy has the potential for serious adverse outcomes and is often used in a vulnerable population. Because adverse effects or failure to maintain benefits is common with long-term use, opioid taper or discontinuation may be indicated in certain patients. Concerns about the adverse individual and population effects of opioids have led to numerous strategies aimed at reductions in prescribing. Although opioid reduction efforts have had generally beneficial effects, there have been unintended consequences. Abrupt reduction or discontinuation has been associated with harms that include serious withdrawal symptoms, psychological distress, self-medicating with illicit substances, uncontrolled pain, and suicide. Key questions remain about when and how to safely reduce or discontinue opioids in different patient populations. Thus, health care professionals who reduce or discontinue long-term opioid therapy require a clear understanding of the associated benefits and risks as well as guidance on the best practices for safe and effective opioid reduction. An interdisciplinary panel of pain clinicians and one patient advocate formulated recommendations on tapering methods and ongoing pain management in primary care with emphasis on patient-centered, integrated, comprehensive treatment models employing a biopsychosocial perspective.

Long-term use of hydrocodone vs. oxycodone in primary care

BACKGROUND

Hydrocodone and oxycodone are the Schedule II opioids most often prescribed in primary care. Notwithstanding the dangers of prescription opioid use, the likelihood of long-term use with either drug is presently unknown.

METHODS

Using a retrospective cohort design and data from a commerical healthcare claims repository, we compared the likelihood of long-term use of hydrocodone and oxycodone in primary care patients presenting with acute back pain. Treatment was categorized as long-term if the prescription dates spanned ≥90 days from initial prescription to the run-out date of the last prescription, and included ≥120 days' supply or ≥10 fills. Instrumental variable methods and probit regression were used to model the effect of drug choice on long-term use, estimate the average treatment effect, and correct for confounding by indication.

RESULTS

A total of 3,983 patients who were prescribed only hydrocodone or only oxycodone were followed for 270 days in 2016. Long-term opioid use was observed in 320 patients (8%). Controlling for potential confounders including morphine milligram equivalents and dosage, an estimated 12% (95 CI, 10%-14%) treated with hydrocodone transitioned to long-term use vs. 2% (95 CI, 1%-3%) on oxycodone. Among patients who received more than one prescription (n = 1,866), an estimated 23% (95 CI, 19%-26%) treated with hydrocodone transitioned to long-term use vs. 5% (95 CI, 3%-7%) on oxycodone. The difference between drugs was supported in sensitivity and subgroup analyses. Sample selection bias was not detected.

CONCLUSIONS

Long-term use was substantially greater for patients treated with hydrocodone than oxycodone, despite equianalgesia.

Adult Cancer Pain, Version 3.2019, NCCN Clinical Practice Guidelines in Oncology

In recent years, the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Adult Cancer Pain have undergone substantial revisions focusing on the appropriate and safe prescription of opioid analgesics, optimization of nonopioid analgesics and adjuvant medications, and integration of nonpharmacologic methods of cancer pain management. This selection highlights some of these changes, covering topics on management of adult cancer pain including pharmacologic interventions, nonpharmacologic interventions, and treatment of specific cancer pain syndromes. The complete version of the NCCN Guidelines for Adult Cancer Pain addresses additional aspects of this topic, including pathophysiologic classification of cancer pain syndromes, comprehensive pain assessment, management of pain crisis, ongoing care for cancer pain, pain in cancer survivors, and specialty consultations.

Lack of Antinociceptive Cross-Tolerance With Co-Administration of Morphine and Fentanyl Into the Periaqueductal Gray of Male Sprague-Dawley Rats

Tolerance to the antinociceptive effect of mu-opioid receptor agonists, such as morphine and fentanyl, greatly limits their effectiveness for long-term use to treat pain. Clinical studies have shown that combination therapy and opioid rotation can be used to enhance opioid-induced antinociception once tolerance has developed. The mechanism and brain regions involved in these processes are unknown. The purpose of this study was to evaluate the contribution of the ventrolateral periaqueductal gray (vlPAG) to antinociceptive tolerance and cross-tolerance between administration and co-administration of morphine and fentanyl. Tolerance was induced by pretreating rats with morphine or fentanyl or low-dose combination of morphine and fentanyl into the vlPAG followed by an assessment of the cross-tolerance to the other opioid. In addition, tolerance to the combined treatment was assessed. Cross-tolerance did not develop between repeated vlPAG microinjections of morphine and fentanyl. Likewise, there was no evidence of cross-tolerance from morphine or fentanyl to the co-administration of morphine and fentanyl. Co-administration did not cause cross-tolerance to fentanyl. Cross-tolerance was only evident to morphine or morphine and fentanyl combined in rats pretreated with co-administration of low doses of morphine and fentanyl. This finding is consistent with the functionally selective signaling that has been reported for antinociception and tolerance after morphine and fentanyl binding to the mu-opioid receptor. This research supports the notion that combination therapy and opioid rotation may be useful clinical practices to decrease opioid tolerance and other side effects. PERSPECTIVE: This preclinical study shows that there is a decrease in cross-tolerance between morphine and fentanyl within the periaqueductal gray, which is a key brain region in opioid antinociception and tolerance.

Pain polymorphisms and opioids: An evidence based review

Despite the various different candidate genetic polymorphisms of potential clinical relevance, there is not enough understanding of the inter-individual variability in analgesic administration. The cytochrome P450 2D6 (CYP2D6) genotype is thought to be one of the most studied. The aim of the present evidence-based review was to determine if there is now sufficient evidence to make clinical recommendations based on a specific genomic profile. The data sources utilized were as follows: PubMed (NLM) database, Evidence Based Medicine Guidelines and Google. Research on clinical guidance standards, systematic reviews, meta-analyses and clinical trials, published prior to January 2018, were evaluated in English, using the MeSH terms ‘cancer pain’, ‘polymorphism’, ‘genetic’ and ‘gene polymorphism’. To assess the level of evidence, the Strength of Recommendation Taxonomy of the American Family Physician was applied. From the initial search, 12 systematic reviews and/or meta-analyses, 5 clinical trials and 10 guidelines were selected. The results indicated that genetic variation of µ-opioid receptor 1 (OPRM1) may contribute to inter-individual differences in morphine consumption with recommendation grade A for OPRM A118G single nucleotide polymorphism (rs1799971). Polymorphisms associated with the metabolization process of morphine and other opioid drugs are very relevant in opioid titration and ethnic subgroup differences which have to be taken into account (particularly, for the recommendation grade A for the CYP2D6 polymorphism). In human studies, the catechol-O-methyl transferase (COMT) genotype affects the efficacy of opioids in acute and chronic pain under different settings, with recommendation grade B to the COMT single nucleotide polymorphism rs4680 (Val/Met). Finally, polymorphisms of the ATP-binding cassette family of efflux transporters were highlighted. Consistent data on pain polymorphisms is now widely available; however, these results have had very little impact on clinical guidelines and daily oncologist practice. Persisting pain, side effects of grade 3 (NCI-CTCAE v4.0) and breakthrough pain with more than 4 episodes/day should be considered the criteria for pain multidisciplinary team discussions and for polymorphism screening.

Practical management of opioid rotation and equianalgesia

Purpose

To review the recent literature on opioid rotation (ie, switching from one opioid drug to another or changing an opioid’s administration route) in cancer patients experiencing severe pain and to develop a novel equianalgesia table for use in routine clinical practice.

Methods

The MEDLINE database was searched with terms “cancer pain,” “opioid rotation,” “opioid switching,” “opioid ratio,” “opioid conversion ratio,” and “opioid equianalgesia” for the major opioids (morphine, oxycodone, fentanyl, and hydromorphone) and the intravenous, subcutaneous, oral, and transdermal administration routes. Selected articles were assessed for the calculated or cited opioid dose ratio, bidirectionality, and use of the oral morphine equivalent daily dose or a direct drug-to-drug ratio.

Results

Twenty publications met our selection criteria and were analyzed in detail. We did not find any large-scale, prospective, double-blind randomized controlled trial with robust design, and most of the studies assessed relatively small numbers of patients. Bidirectionality was investigated in seven studies only.

Conclusion

The updated equianalgesic table presented here incorporates the latest data and provides information on bidirectionality. Despite the daily use of equianalgesic tables, they are not based on high-level scientific evidence. More clinical research is needed on this topic.

Prospective evaluation of chronic pain disorders and treatments

BACKGROUND

The incidence of chronic pain is variable among individuals who have sustained traumatic or surgical injury. Also, treatments for pain rarely are effective consistently for a procedure or agent, and no therapies are considered effective for pain that is chronic.

NEW METHOD

Difficulties with standard methods for conducting clinical trials call attention to a need for protocols that provide a new understanding of the development of and control over chronic pain. Prospective single-subject research designs can document varieties of pain progression over time for individuals. Subsequent grouping of individuals with common characteristics directs a mechanism-based approach to therapy.

RESULTS

Tracking of individuals' pain and associated influences over time is consistent with clinical practice, noting and adapting to changes that occur.

COMPARISON WITH EXISTING METHODS

Grouping patients with diverse characteristics and variable effects of therapy is problematic. Conventional evaluation of pain assesses patients with similar injuries or surgery without characterizations of individuals who develop chronic pain or recover over time. Also, classical evaluation of therapies involves comparison of groups receiving treatment or a placebo without characterization of patients with successful and unsuccessful results.

CONCLUSIONS

Single-subject prospective studies can inform clinical trials according to individual differences that would be obscured by comparison of groups with unknown variation in characteristics that influence pain and therapeutic effectiveness.

Methods of Rotation From Another Strong Opioid to Methadone for the Management of Cancer Pain: A Systematic Review of the Available Evidence

CONTEXT

Up to 44% of patients with cancer-related pain require opioid rotation (OR) because of inadequate analgesia or side effects. No consensus exists regarding the most efficacious method for rotation to methadone.

OBJECTIVES

To define the available evidence regarding methods of rotation to methadone and to determine if sufficient evidence exists regarding the superiority of one method.

METHODS

A predefined search strategy, using Medical Subject Headings (MeSH) search terms and keywords combined using Boolean operators, was performed. Study selection was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance. Data were extracted, quality of studies assessed, and narrative synthesis undertaken.

RESULTS

A total of 3214 potentially relevant studies were identified. Twenty-five studies were included: 15 retrospective and 10 prospective (n = 1229). One trial compared three-day switch (3DS) and rapid conversion (RC) methods; two, 3DS; 10, RC; nine, ad libitum (AL). Success rates were as follows: 3DS-93%, RC-71.7%, and AL-92.8%. The single clinical trial and retrospective studies demonstrated poorer analgesia and an excess of adverse events (AEs) in the RC group (five dropouts because of AEs) compared with the 3DS group (no severe AEs). Time to stable analgesia was as follows: RC <4.3 days and AL <6 days.

CONCLUSION

Evidence identified was mainly from uncontrolled observational studies, making causality difficult to establish. Studies were heterogeneous in methodology and outcome measures. There was a trend toward excess AEs using the RC method, in comparison to the AL and 3DS methods. The methodological quality of the AL studies was low. A direct comparison of AL and 3DS methods would be informative.

A multicenter, primary-care-based, open-label study to assess the success of converting opioid-experienced patients with chronic moderate-to-severe pain to morphine sulfate and naltrexone hydrochloride extended-release capsules using a standardized conversion guide

OBJECTIVE

To evaluate the conversion of opioid-experienced patients with chronic moderate-to-severe pain to extended-release morphine sulfate with sequestered naltrexone hydrochloride (MSN) using a standardized conversion guide.

METHODS

This open-label, single-arm study was conducted in 157 primary care centers in the United States. A total of 684 opioid-experienced adults with chronic moderate-to-severe pain were converted to oral administration of MSN from transdermal fentanyl and oral formulations of hydrocodone, hydromorphone, methadone, oxycodone, oxymorphone, and other morphine products using a standardized conversion guide. The primary endpoint was the percentage of patients achieving a stable MSN dose within a 6-week titration phase. Secondary endpoints included duration of time to stable dose, number of titration steps, safety and efficacy measures, and investigator assessment of conversion guide utility.

RESULTS

Of the 684 patients, 51.3% were converted to a stable dose of MSN (95% confidence interval: 47.5%, 55.1%). The mean (standard deviation) number of days to stable dose was 20 (8.94), and number of titration steps to stable dose was 2.4 (1.37). The majority of adverse events were mild/moderate and consistent with opioid therapy. Mean pain scores at stable dose decreased from baseline. Investigators were generally satisfied with the conversion guide and, in 94% of cases, reported they would use it again.

CONCLUSION

Conversion to MSN treatment using the standardized MSN conversion guide was an attainable goal in approximately half of the population of opioid-experienced patients with chronic moderate-to-severe pain. Investigators found the guide to be a useful tool to assist conversion of opioid-experienced patients to MSN.

N-terminal guanidinylation of the cyclic 1,4-ureido-deltorphin analogues: the synthesis, receptor binding studies, and resistance to proteolytic digestion

The synthesis of a series of N-guanidinylated cyclic ureidopeptides, analogues of 1,4-ureido-deltorphin/dermorphine tetrapeptide is described. The δ- and μ-opioid receptor affinity of new guanidinylated analogues and their non-guanidinylated precursors was determined by the displacement radioligand binding experiments. Our results indicate that the guanidinylation of cyclic 1,4-ureidodeltorphin peptide analogues does not exhibit a uniform influence on the opioid receptor binding properties, similarly as reported earlier for some linear peptides. All analogues were also tested for their in vitro resistance to proteolysis during incubation with large excess of chymotrypsin, pepsin, and papain by means of mass spectroscopy. Guanidinylated ureidopeptides 1G-4G showed mixed μ agonist/δ agonist properties and high enzymatic stability indicating their potential as therapeutic agents for treatment of pain.

Morphine or oxycodone for cancer-related pain? A randomized, open-label, controlled trial

CONTEXT

There is wide interindividual variation in response to morphine for cancer-related pain; 30% of patients do not have a good therapeutic outcome. Alternative opioids such as oxycodone are increasingly being used, and opioid switching has become common clinical practice.

OBJECTIVES

To compare clinical response to oral morphine vs. oral oxycodone when used as first-line or second-line (after switching) treatment in patients with cancer-related pain.

METHODS

In this prospective, open-label, randomized, controlled trial (ISRCTN65155201) with a selected crossover phase, patients with cancer-related pain were randomized to receive either oral morphine or oxycodone as first-line treatment. Dose was individually titrated until the patient reported adequate pain control. Patients who did not respond to the first-line opioid (either because of inadequate analgesia or unacceptable adverse effects) were switched to the alternative opioid.

RESULTS

Two hundred patients were recruited. On intention-to-treat analysis (n = 198, morphine 98, oxycodone 100), there was no significant difference between the numbers of patients responding to morphine (61/98 = 62%) or oxycodone (67/100 = 67%) when used as a first-line opioid. Similarly, there was no significant difference in subsequent response when patients were switched to either morphine (8/12 = 67%) or oxycodone (11/21 = 52%). Per-protocol analysis demonstrated a 95% response rate when both opioids were available. There was no difference in adverse reaction scores between morphine and oxycodone either in first-line responders or nonresponders.

CONCLUSION

In this population, there was no difference between analgesic response or adverse reactions to oral morphine and oxycodone when used as a first- or second-line opioid. These data provide evidence to support opioid switching to improve outcomes.

Toward a systematic approach to opioid rotation

Patients requiring chronic opioid therapy may not respond to or tolerate the first opioid prescribed to them, necessitating rotation to another opioid. They may also require dose increases for a number of reasons, including worsening disease and increased pain. Dose escalation to restore analgesia using the primary opioid may lead to increased adverse events. In these patients, rotation to a different opioid at a lower-than-equivalent dose may be sufficient to maintain adequate tolerability and analgesia. In published trials and case series, opioid rotation is performed either using a predetermined substitute opioid with fixed conversion methods, or in a manner that appears to be no more systematic than trial and error. In clinical practice, opioid rotation must be performed with consideration of individual patient characteristics, comorbidities (eg, concurrent psychiatric, pulmonary, renal, or hepatic illness), and concurrent medications, using flexible dosing protocols that take into account incomplete opioid cross-tolerance. References cited in this review were identified via a search of PubMed covering all English language publications up to May 21, 2013 pertaining to opioid rotation, excluding narrative reviews, letters, and expert opinion. The search yielded a total of 129 articles, 92 of which were judged to provide relevant information and subsequently included in this review. Through a review of this literature and from the authors’ empiric experience, this review provides practical information on performing opioid rotation in clinical practice.

Dosing considerations with transdermal formulations of fentanyl and buprenorphine for the treatment of cancer pain

Opioids continue to be first-line pharmacotherapy for patients suffering from cancer pain. Unfortunately, subtherapeutic dosage prescribing of pain medications remains common, and many cancer patients continue to suffer and experience diminished quality of life. A large variety of therapeutic options are available for cancer pain patients. Analgesic pharmacotherapy is based on the patient’s self-report of pain intensity and should be tailored to meet the requirements of each individual. Most, if not all, cancer pain patients will ultimately require modifications in their opioid pharmacotherapy. When changes in a patient’s medication regimen are needed, adequate pain control is best maintained through appropriate dosage conversion, scheduling immediate release medication for withdrawal prevention, and providing as needed dosing for breakthrough pain. Transdermal opioids are noninvasive, cause less constipation and sedation when compared to oral opioids, and may improve patient compliance. A relative potency of 100:1 is recommended when converting the patient from oral morphine to transdermal fentanyl. Based on the limited data available, there is significant interpatient variability with transdermal buprenorphine and equipotency recommendations from oral morphine of 75:1–110:1 have been suggested. Cancer patients may require larger transdermal buprenorphine doses to control their pain and may respond better to a more aggressive 75–100:1 potency ratio. This review outlines the prescribing of transdermal fentanyl and transdermal buprenorphine including how to safely and effectively convert to and use them for those with cancer pain.

The role of analgesic adjustment strategies in achieving analgesic efficacy in opioid-tolerant hospice patients in China

Diverse strategies of analgesic adjustment are often, respectively, used to sustain analgesic efficiency for opioid-tolerant patients with different refractory factors of pain. In order to select effective analgesic adjustment strategy for hospice patient without knowing explicit causes of diminishing analgesic efficiency, a retrospective data of 743 patients among 3760 hospice patients were analyzed. The efficacy and adverse effects were not significantly different among analgesic adjustment strategies at each adjustment. Opioid duration was not associated with clinical characteristics. For opioid-tolerant hospice patients, the analgesic adjustment strategy can be selected for individual patient. After repeated analgesic adjustments, opioid tapering may also occur.

[Cancer pain management]

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

Hydromorphone: evolving to meet the challenges of today's health care environment

BACKGROUND

Hydromorphone, a potent analogue of morphine, has long had an important role in pain management and is included in several international guidelines for managing pain. Advances in hydromorphone formulations and the ways in which hydromorphone is being used clinically today warrant a review of the drug's pharmacotherapeutic utility.

OBJECTIVE

The history and recent advances in hydromorphone pharmacotherapy are reviewed. Areas covered include the pharmacologic and metabolic profile of hydromorphone, the role of hydromorphone in pain management, formulations and routes of administration, and issues related to relative opioid potencies, equianalgesic ratios, and opioid rotation. Because hydromorphone, like all opioids, carries a risk of misuse, abuse, and illicit diversion, the related issues of tamper-resistant formulations and "dose-dumping" of extended-release formulations are discussed.

CONCLUSIONS

Due to the epidemic of prescription opioid overdoses associated with prescription opioid abuse in the United States, development of tamper-resistant opioid formulations that avoid dose-dumping issues has become a significant goal of pharmaceutical manufacturers. The current formulation of hydromorphone extended-release potentially provides the benefits of long-acting hydromorphone (ie, continuous pain control, increased quality of life, freedom to perform daily activities) to appropriate patients, while reducing the risks of abuse and without compromising safety.

Analgesia and central side-effects: two separate dimensions of morphine response

AIMS

To present a statistical model for defining interindividual variation in response to morphine and to use this model in a preliminary hypothesis-generating multivariate genetic association study.

METHODS

Two hundred and sixty-four cancer patients taking oral morphine were included in a prospective observational study. Pain and morphine side-effect scores were examined using principal components analysis. The resulting principal components were used in an exploratory genetic association study of single nucleotide polymorphisms across the genes coding for the three opioid receptors, OPRM1, OPRK1 and OPRD1. Associations in multivariate models, including potential clinical confounders, were explored.

RESULTS

Two principal components corresponding to residual pain and central side-effects were identified. These components accounted for 42 and 18% of the variability in morphine response, respectively, were independent of each other and only mildly correlated. The genetic and clinical factors associated with these components were markedly different. Multivariate regression modelling, including clinical and genetic factors, accounted for only 12% of variability in residual pain on morphine and 3% of variability in central side-effects.

CONCLUSIONS

Although replication is required, this data-driven analysis suggests that pain and central side-effects on morphine may be two separate dimensions of morphine response. Larger study samples are necessary to investigate potential genetic and clinical associations comprehensively.

Differences between opioids: pharmacological, experimental, clinical and economical perspectives

Clinical studies comparing the response and side effects of various opioids have not been able to show robust differences between drugs. Hence, recommendations of the regulatory authorities have been driven by costs with a general tendency in many countries to restrict physician's use of opioids to morphine. Although this approach is recognized as cost-effective in most cases there is solid evidence that, on an individual patient basis, opioids are not all equal. Therefore it is important to have an armamentarium of strong analgesics in clinical practice to ensure a personalized approach in patients who do not respond to standard treatment. In this review we highlight differences between opioids in human studies from a pharmacological, experimental, clinical and health economics point of view. We provide evidence that individuals respond differently to opioids, and that general differences between classes of opioids exist. We recommend that this recognition is used to individualize treatment in difficult cases allowing physicians to have a wide range of treatment options. In the end this will reduce pain and side effects, leading to improved quality of life for the patient and reduce the exploding pain related costs.

Quality assessment of the methods used in published opioid conversion reviews

The study objective was to assess methodological quality of opioid conversion systematic reviews. The electronic databases PubMed, EMBASE, and Scopus were used to identify the systematic reviews from the earliest available date until April 2012. Studies were not restricted based on type of opioid, country, or languages. Methodological quality was evaluated using the "Assessment of Multiple Systematic Reviews (AMSTAR)." A total of 2772 articles were found from which five met inclusions criteria. No review mentioned about the duplicate study selection and data extraction. Two reviews included a list of studies that were excluded studies. One study did not provided information on the characteristics of primary studies that were included. Of the three reviews that evaluated the quality of primary studies, two used the quality of included studies in formulating conclusions. Only two reviews provided information about conflicts of interest. Of the five included systematic reviews, three reached a moderate score; two had poor quality. Specific recommendations to improve methodological quality would include performing the data selection and extraction in duplicate, listing or showing the flowchart of studies that were included and excluded along with the reasons, including the main studies data illustrating tables, and including an assessment of the quality of the primary included studies.

Validity testing of patient objections to acceptance of tamper-resistant opioid formulations

Background

Tamper-resistant formulations (TRFs) of oral opioid drugs are intended to prevent certain types of abuse (eg, intranasal, intravenous). Patients raising objections to receiving a TRF may have valid concerns or may be seeking a formulation that can be more easily misused.

Methods

US clinicians experienced in pain management met in October 2011 to discuss common patient objections to being switched from a non-TRF opioid to a TRF of the same opioid. Retail pharmacy, health insurance, and scientific data were used to assess the potential validity of these patient objections.

Results

Clinical experience switching patients from a non-TRF to a TRF opioid was limited to oxycodone controlled release (CR), as it was the only TRF available at that time; knowledge of other TRFs was limited to the scientific literature. Common objections from patients included “costs more,” “not covered by insurance,” “can’t feel it working,” and “causes adverse events.” Objective retail pharmacy and insurance coverage information for oxycodone CR was accessible and indicated that patient objections were based on cost and coverage varied by insurer. Unpublished trial results (ClinicalTrials.gov) revealed that TRF oxycodone CR has a slower initial release than the non-TRF formulation, which may reduce positive subjective effects. The complaint “I can’t feel it working” may reflect lessened positive subjective effects rather than reduced analgesic efficacy. Most tolerability complaints lacked objective support.

Conclusion

The general process used to assess the validity of patient objections to TRF oxycodone CR may be applied to other TRFs once they become available. Publication of clinical data on TRFs would help clinicians to appropriately weigh patient concerns.

Consequences of the 118A>G polymorphism in the OPRM1 gene: translation from bench to bedside?

The 118A>G single nucleotide polymorphism (SNP) in the μ-opioid receptor (OPRM1) gene has been the most described variant in pharmacogenetic studies regarding opioid drugs. Despite evidence for an altered biological function encoded by this variant, this knowledge is not yet utilized clinically. The aim of the present review was to collect and discuss the available information on the 118A>G SNP in the OPRM1 gene, at the molecular level and in its clinical manifestations. In vitro biochemical and molecular assays have shown that the variant receptor has higher binding affinity for β-endorphins, that it has altered signal transduction cascade, and that it has a lower expression compared with wild-type OPRM1. Studies using animal models for 118A>G have revealed a double effect of the variant receptor, with an apparent gain of function with respect to the response to endogenous opioids but a loss of function with exogenous administered opioid drugs. Although patients with this variant have shown a lower pain threshold and a higher drug consumption in order to achieve the analgesic effect, clinical experiences have demonstrated that patients carrying the variant allele are not affected by the increased opioid consumption in terms of side effects.

Effectiveness and gastrointestinal tolerability during conversion and titration with once-daily OROS® hydromorphone extended release in opioid-tolerant patients with chronic low back pain

Purpose

To describe the efficacy and safety of hydromorphone extended-release tablets (OROS hydromorphone ER) during dose conversion and titration.

Patients and methods

A total of 459 opioid-tolerant adults with chronic moderate to severe low back pain participated in an open-label, 2- to 4-week conversion/titration phase of a double-blind, placebo-controlled, randomized withdrawal trial, conducted at 70 centers in the United States. Patients were converted to once-daily OROS hydromorphone ER at 75% of the equianalgesic dose of their prior total daily opioid dose (5:1 conversion ratio), and titrated as frequently as every 3 days to a maximum dose of 64 mg/day. The primary outcome measure was change in pain intensity numeric rating scale; additional assessments included the Patient Global Assessment and the Roland–Morris Disability Questionnaire scores. Safety assessments were performed at each visit and consisted of recording and monitoring all adverse events (AEs) and serious AEs.

Results

Mean (standard deviation) final daily dose of OROS hydromorphone ER was 37.5 (17.8) mg. Mean (standard error of the mean [SEM]) numeric rating scale scores decreased from 6.6 (0.1) at screening to 4.3 (0.1) at the final titration visit (mean [SEM] change, −2.3 [0.1], representing a 34.8% reduction). Mean (SEM) change in Patient Global Assessment was −0.6 (0.1), and mean change (SEM) in the Roland–Morris Disability Questionnaire was −2.8 (0.3). Patients achieving a stable dose showed greater improvement than patients who discontinued during titration for each of these measures (P < 0.001). Almost 80% of patients achieving a stable dose (213/268) had a ≥30% reduction in pain. Commonly reported AEs were constipation (15.4%), nausea (11.9%), somnolence (8.7%), headache (7.8%), and vomiting (6.5%); 13.0% discontinued from the study due to AEs.

Conclusion

The majority of opioid-tolerant patients with chronic low back pain were successfully converted to effective doses of OROS hydromorphone ER within 2 to 4 weeks.

Converting to transdermal fentanyl: avoidance of underdosing

BACKGROUND

Converting between the various opioid agents continues to be challenge for many practitioners. Specifically, variable recommendations for converting to the transdermal fentanyl patch may lead to confusion among clinicians and errors in dosing.

OBJECTIVE

Our aim was to describe the inconsistencies among available opioid conversions with regard to transdermal fentanyl and to provide recommendations for safe and effective utilization of this product in patients with chronic pain.

RESULTS

Available reports support the use of the morphine intravenous to oral ratio of 1:3 during the conversion to transdermal fentanyl product.

CONCLUSIONS

Underdosing is an often overlooked complication of switching to transdermal fentanyl. Current recommendations for converting to transdermal fentanyl do not reflect contemporary clinical practice and should be reevaluated.

Tapentadol prolonged release versus strong opioids for severe, chronic low back pain: results of an open-label, phase 3b study

INTRODUCTION

This open-label, phase 3b study evaluated the effectiveness and tolerability of oral tapentadol prolonged release (PR; 50-250 mg twice daily [b.i.d.]) for managing severe, chronic low back pain in patients responding to World Health Organization (WHO) step III opioids but tolerating treatment poorly. Equianalgesic ratios for tapentadol to prior strong opioids were calculated.

METHODS

Patients rotated directly from prior WHO step III opioids to tapentadol. Patients received tapentadol PR (50-250 mg b.i.d.) during 5-week titration and 7-week maintenance periods. Tapentadol immediate release (IR) 50 mg (≤ twice/day, ≥ 4 h apart) was allowed (total daily dose of tapentadol PR and IR ≤ 500 mg/day). The primary endpoint was responder rate 1 at week 6 (percentage of patients with the same or less pain intensity [11-point numerical rating scale (NRS; 3-day average)] vs week -1).

RESULTS

Responder rate 1 at week 6 (last observation carried forward [LOCF]) was 80.9% (76/94; P < 0.0001 vs. the null responder hypothesis rate [<60%]), resulting in a positive trial despite premature termination (136 recruited of 180 planned). Significant improvements from baseline in pain intensity and neuropathic pain symptoms were observed at weeks 6 and 12 with tapentadol PR (P < 0.05). Equianalgesic ratios were calculated for PR formulations alone and for PR and IR formulations combined for tapentadol to oxycodone, buprenorphine, fentanyl, morphine, and hydromorphone. The prevalences of adverse events reported as the reason for switching to tapentadol (most commonly constipation and nausea) decreased over time.

CONCLUSIONS

Tapentadol PR (50-250 mg b.i.d.) provided at least comparable pain relief and improved tolerability versus prior strong opioids in patients with severe, chronic low back pain responding to WHO step III therapy. Conversion from strong opioids to tapentadol PR, with its two mechanisms of action, went smoothly considering overall effectiveness and tolerability outcomes. Equianalgesic ratios of tapentadol to oxycodone and other strong opioids were in line with other phase 3/3b studies.

The implications of tamper-resistant formulations for opioid rotation

Because rates of both opioid prescribing and opioid abuse have increased, drug companies have responded by considering strategies to make opioid formulations less attractive for abuse without compromising safety or efficacy for patients with legitimate pain management needs. The emergence of tamper-resistant opioid formulations is intended to deter abuse by creating obstacles to crushing or dissolving opioid tablets and capsules. At present, 2 long-acting and 1 immediate-release (IR) opioids are available in tamper-resistant formulations. Oxycodone controlled-release and oxymorphone extended-release tablets have each been reformulated with a hardened matrix that resists crushing or dissolution in liquids, making them difficult to prepare for nasal insufflation or intravenous use. Oxycodone IR has been reformulated with aversive ingredients that create nasal discomfort if the tablet is crushed and insufflated. Tamper-resistant opioid formulations are likely to be selected for patients who are identified as being at risk for abuse. However, patients vary in their response to individual opioids and may require rotation to a series of alternative opioids before finding one that is effective and sufficiently well tolerated. With only a few tamper-resistant opioid formulations currently available, switching and rotation may become difficult. As a result, patients who do not respond to a tamper-resistant opioid formulation or experience intolerable adverse events may require rotation to a formulation without tampering safeguards. Prescribers will need to be on guard for patients who may make false claims of poor response or adverse events to avoid tamper-resistant opioid formulations. Moreover, prescribers need to be aware of any tamper-resistance mechanisms that may affect efficacy or tolerability in patients with legitimate pain management needs compared with formulations without tampering safeguards.

Opioid switching in patients with advanced cancer followed at home. A retrospective analysis

CONTEXT

Opioid switching has been found to improve opioid responsiveness in different conditions. However, data on opioid switching performed at home are almost nonexistent, despite the fact that most patients are followed at home.

OBJECTIVES

The aim of this retrospective survey was to determine frequency, indications, usefulness, and safety of opioid switching when treating advanced cancer-related pain in patients followed at home.

METHODS

A retrospective review of data from patients with advanced cancer followed at home by three home care teams for a period of two years was performed. Patients who had their opioids switched were selected. Reasons for switching opioid doses and routes of administration and outcomes were collected.

RESULTS

Two hundred one (17%) of 1141 patients receiving "strong" opioids were switched. The mean Karnofsky Performance Status score was 35.6, and the median survival was 30 days. The most frequent reason to switch was for convenience, and the most frequent switch was to parenteral morphine. In most patients, a better analgesic response was observed. Patients who were switched to parenteral morphine had a shorter survival in comparison with other opioid sequences (P<0.0005). After switching, opioid doses were increased by 23% and 41%, after a week and at time of death, respectively.

CONCLUSION

Opioid switching was useful for most patients in the home environment, at least in less complex circumstances, when done by experienced home care teams. Prospective studies are needed to provide information about the decision to admit to hospital for this purpose and the predictive factors that may relatively contraindicate transportation to a facility in severely ill patients.

Treatment of chronic pain in older people: evidence-based choice of strong-acting opioids

In the treatment of chronic malignant and non-malignant pain, opioids are used as strong analgesics. Frail elderly patients often have multiple co-morbidities and use multiple medicines, leading to an increased risk of clinically relevant drug-drug and drug-disease interactions. Age-related changes and increased frailty may lead to a less predictable drug response, increased drug sensitivity, and potential harmful drug effects. As a result, physicians face a complex task in prescribing medication to elderly patients. In this review, the appropriateness of the strong-acting opioids buprenorphine, fentanyl, hydromorphone, methadone, morphine, oxycodone and tapentadol is determined for use in elderly patients. Evidence-based recommendations for prescribing strong opioids to the frail elderly are presented. A literature search was performed for all individual drugs, using a validated and published set of 23 criteria concerning effectiveness, safety, pharmacokinetics and pharmacodynamics, experience, and convenience in elderly patients. First, information on the criteria was obtained from pharmaceutical reference books and a MEDLINE search. The information obtained on the individual drugs in the class of opioids was compared with the reference drug morphine. Evidence-based recommendations were formulated on the basis of the pros and cons for the frail elderly. Using the set of 23 criteria, no differentiation can be made between the appropriateness of buprenorphine, fentanyl, hydromorphone, morphine and oxycodone for use in elderly patients. Methadone has strong negative considerations in the treatment of chronic pain in the frail elderly. Methadone has a high drug-drug interaction potential and is associated with prolongation of the QT interval and a potential risk of accumulation due to a long elimination half-life. In addition, methadone is difficult to titrate because of its large inter-individual variability in pharmacokinetics, particularly in the frail elderly. Because of a lack of empiric knowledge, the use of tapentadol is not recommended in frail elderly persons. Nevertheless, tapentadol may prove to be a useful analgesic for the treatment of chronic pain in frail elderly persons because of its possible better gastrointestinal tolerability. In the treatment of chronic pain in the frail elderly, the opioids of first choice are buprenorphine, fentanyl, hydromorphone, morphine and oxycodone. In order to improve the convenience for elderly patients, the controlled-release oral dosage forms and transdermal formulations are preferred.

Safety and Tolerability of Once-Daily OROS(®) hydromorphone extended-release in opioid-tolerant adults with moderate-to-severe chronic cancer and noncancer pain: pooled analysis of 11 clinical studies

CONTEXT

The efficacy and tolerability of once-daily hydromorphone extended release (ER) (OROS(®) hydromorphone ER, Exalgo(®), Mallinckrodt Brand Pharmaceuticals, Inc., Hazelwood, MO) in patients with chronic cancer and noncancer pain have been reported in previous studies.

OBJECTIVES

The objective of this analysis was to assess the pooled safety data of OROS hydromorphone ER in opioid-tolerant patients with chronic cancer and noncancer pain.

METHODS

Safety results were pooled from 11 clinical studies in opioid-tolerant patients: one 12-week, double-blind, placebo-controlled study; three active-controlled studies; and seven uncontrolled studies (durations of three to 52 weeks). Patients were included in this analysis if they took ≥1 dose of study medication. Descriptive statistics were used to analyze baseline and demographic characteristics, supplemental analgesic use, and incidence of adverse events (AEs).

RESULTS

In total, 1251 opioid-tolerant patients received ≥1 dose of OROS hydromorphone ER. Mean (SD) duration of exposure was 43.1 (67.8) days (range 1-396 days), and mean (SD) daily dose was 43.4 (47.1) mg. Overall, 1081 patients (86.4%) used supplemental rescue analgesics. The overall incidence of AEs was 76.9%. The most frequently reported AEs were nausea (23.2%), constipation (22.4%), vomiting (14.4%), somnolence (12.9%), and headache (12.8%). Treatment-related constipation occurred in 20.5% of patients, nausea in 16.8%, somnolence in 11.8%, vomiting in 8.2%, and headache in 7.0%. Serious adverse events occurred in 13.5% of patients, with the most frequently reported serious adverse events being dehydration, nausea, and vomiting. No treatment-related deaths occurred.

CONCLUSION

Once-daily OROS hydromorphone ER demonstrated a safety and tolerability profile in opioid-tolerant patients that is consistent with the known safety profiles of opioids.

A review of pharmacotherapy for chronic low back pain with considerations for sports medicine

Up to 30% of athletes experience low back pain (LBP) depending on sport type, sex, training intensity and frequency, and technique. United States clinical guidelines define back pain as chronic if it persists for ≥ 12 weeks, and subacute if it persists 4 to < 12 weeks. Certain sports injuries are likely to lead to chronic pain. Persistent or chronic symptoms are frequently associated with degenerative lumbar disc disease or spondylolytic stress lesions. Exercise therapy is widely used and is the most conservative form of treatment for chronic LBP (cLBP). Pharmacotherapies for cLBP include acetaminophen, nonsteroidal anti-inflammatory drugs, and opioids. Acetaminophen is a well-tolerated first-line pharmacotherapy, but high-dose, long-term use is associated with hepatic toxicity. Nonsteroidal anti-inflammatory drugs can be an effective second-line option if acetaminophen proves inadequate but they have well-known risks of gastrointestinal, cardiovascular, and other systemic adverse effects that increase with patient age, dose amount, and duration of use. The serotonin-norepinephrine reuptake inhibitor, duloxetine, has demonstrated modest efficacy and is associated with systematic adverse events, including serotonin syndrome, which can be dose related or result from interaction with other analgesics. Opioids may be an effective choice for moderate to severe pain but also have significant risks of adverse events and carry a substantial risk of addiction and abuse. Because the course of cLBP may be protracted, patients may require treatment over years or decades, and it is critical that the risk/benefit profiles of pharmacotherapies are closely evaluated to ensure that short- and long-term treatments are optimized for each patient. This article reviews the clinical evidence and the guideline recommendations for pharmacotherapy of cLBP.

Opioid rotation in clinical practice

INTRODUCTION

Although chronic opioid therapy is usually initiated using short-acting opioids, many patients with chronic pain are subsequently converted to long-acting and extended-release preparations. In clinical practice, optimal management requires careful individualization of dosage in order to achieve an appropriate balance of efficacy and adverse effects. After successful initiation and stabilization of opioid treatment, subsequent changes in regimen may still be required to maintain efficacy with an acceptable adverse effect profile.

METHODS

This is a qualitative review of the available literature from June 2012 or earlier on opioid rotation for the management of chronic pain in the clinical setting. The PubMed database was searched using various search terms, and additional articles were identified through manual search of the bibliographies of articles identified through the PubMed search. Papers were selected based on relevance to the topic.

RESULTS

When considering opioid rotation, clinicians must take into account not only the significant differences in potency among opioid drugs but also the considerable interpatient variability in response to opioids. The estimate of relative potency used in calculating an appropriate starting dose when switching from one opioid to another has been codified on equianalgesic dose tables. To reduce the risk of unintentional overdose, a two-step calculation has been proposed, which incorporates an initial reduction (typically 25-50%) in the equianalgesic dose followed by a second evaluation based on the severity of pain at the time of rotation along with other medical or psychosocial factors that might alter the effectiveness and tolerability of the new drug. Given the uncertainty of accurately predicting a patient's response to treatment, each initial exposure to a new opioid should be considered a discrete clinical trial to assess the degree of response. Systematic reviews of opioid rotation have documented the re-establishment of adequate pain control or reduced adverse effects in 50-80% of patients.

CONCLUSIONS

Although continued research is needed to refine equianalgesic doses further, opioid rotation is an important and necessary practice in patients with chronic cancer or noncancer pain that is refractory to the initially used opioid.

Polypharmacy and the role of physical medicine and rehabilitation

Polypharmacy and inappropriate prescribing practices lead to higher rates of mortality and morbidity, particularly in vulnerable populations, such as the elderly and those with complex medical conditions. Physical medicine and physiatrists face particular challenges given the array of symptoms treated across a spectrum of conditions. This clinical review focuses on polypharmacy and the associated issue of potentially inappropriate prescribing. The article begins with a review of polypharmacy along with relevant aspects of pharmacokinetics and pharmacodynamics in the elderly. The adverse effects and potential hazards of selected medications commonly initiated and managed by rehabilitation specialists are then discussed with specific attention to pain medications, neurostimulants, antipsychotics, antidepressants, antispasmodics, sleep medications, and antiepileptics. Of particular concern is the notion that an adverse effect of one medication can mimic an indication for another and lead to a prescribing cascade and further adverse medication events. Appropriate prescribing practices mandate an accurate, current medication list, yet errors and inaccuracies often plague such lists. The evidence to support explicit (medications to avoid) and implicit (how to evaluate) criteria is presented along with the role of physicians and patients in prescribing medications. A brief discussion of "medication debridement" or de-prescribing strategies follows. In the last section, we draw on the essence of physiatry as a team-based endeavor to discuss the potential benefits of collaboration. In working to optimize medication prescribing, efforts should be made to collaborate not only with pharmacists and other medical specialties but with members of inpatient rehabilitation teams as well.

Strategies to reduce the tampering and subsequent abuse of long-acting opioids: potential risks and benefits of formulations with physical or pharmacologic deterrents to tampering

Increased prescribing of opioid analgesics for chronic noncancer pain may reflect acceptance that opioid benefits outweigh risks of adverse events for a broadening array of indications and patient populations; however, a parallel increase in the abuse, misuse, and diversion of prescription opioids has resulted. There is an urgent need to reduce opioid tampering and subsequent abuse without creating barriers to safe, effective analgesia. Similar to the "magic bullet" concept of antibiotic development (kill the bacteria without harming the patient), the idea behind reformulating opioid analgesics is to make them more difficult to tamper with and abuse by drug abusers but innocuous to the compliant patient. As antibiotics exploit differences in bacterial and human physiology, tamper-resistant formulations depend on differences in the way drug abusers and compliant patients consume opioids. Most opioid abusers tamper with tablets to facilitate oral, intranasal, or intravenous administration, whereas compliant patients usually take intact tablets. Pharmaceutical strategies to deter opioid abuse predominantly focus on tablet tampering, incorporating physical barriers (eg, crush resistance) or embedded chemicals that render tampered tablets inert, unusable, or noxious. Deterring tampering and abuse of intact tablets is more challenging. At present, only a few formulations with characteristics designed to oppose tampering for abuse have received approval by the US Food and Drug Administration, and none has been permitted to include claims of abuse deterrence or tamper resistance in their labeling. This review discusses the potential benefits, risks, and limitations associated with available tamper-resistant opioids and those in development.

The effect of age on opioid switching to methadone: a systematic review

BACKGROUND

The aim of this review was to assess from the existing literature the effect of age on the outcome of opioid switching to methadone, and the possible influence on conversions ratios.

DISCUSSION

Older patients represent a challenge for physicians, as a further factor may play a role in dosing methadone and possibly on successful switching. Although existing data are not conclusive because this aspect did not receive particular attention in most studies, at the present time age has not been found to be independently associated with the dose ratio. Further prospective studies in a large sample of patients, subgrouped for classes of age, opioid doses, and reasons to switch, should be designed to provide more information.

A review of opioids for in-hospital pain management

In the postoperative pain setting, the use of opioid analgesics remains essential in achieving effective analgesia and in avoiding the deleterious sequelae of uncontrolled pain that can worsen patient outcomes. However, postoperative pain remains undertreated in many patients. Choosing the most appropriate use of opioids in the postoperative setting, especially for patients undergoing ongoing opioid treatment for chronic pain, can pose daunting challenges for many clinicians. In this article, we examine the pitfalls that may be encountered when implementing postoperative pain management strategies with opioid analgesics, especially in patients receiving chronic opioid therapy prior to admission, and the critical steps for appropriate and effective analgesia in this setting.

Opioid rotation with extended-release opioids: where should we begin?

Opioid rotation is a common and necessary clinical practice in the management of chronic non-cancer pain to improve therapeutic efficacy with the lowest opioid dose. When dose escalations fail to achieve adequate analgesia or are associated with intolerable side effects, a trial of a new opioid should be considered. Much of the scientific rationale of opioid rotation is based on the wide interindividual variability in sensitivity to opioid analgesics and the novel patient response observed when introducing an opioid-tolerant patient to a new opioid. This article discusses patient indicators for opioid rotation, the conversion process between opioid medications, and additional practical considerations for increasing the effectiveness of opioid therapy during a trial of a new opioid. A Patient vignette that demonstrates a step-wise approach to opioid rotation is also presented.

Switching from oxycodone to methadone in advanced cancer patients

PURPOSE

The aim of this study was to prospectively evaluate the outcomes and the conversion ratio of switching from oxycodone to methadone in advanced cancer patients admitted to an acute palliative care unit.

PATIENTS AND METHODS

A prospective study was carried out on a cohort of consecutive sample of patients receiving oxycodone, who were switched for different reasons mainly because of an inconvenient balance between analgesia and adverse effects. An initial conversion ratio between oxycodone and methadone was 3.3:1. Intensity of pain and symptoms associated with opioid therapy were recorded, and a distress score (DS) was also calculated as a sum of symptom intensity. A successful switching was considered when the intensity of pain and/or DS or the principal symptom requiring switching decreased at least of 33% of the value recorded before switching.

RESULTS

Nineteen out of 542 patients admitted to the unit in 1 year underwent a switching from oxycodone to methadone. Almost all substitutions were successful. The prevalent indication for opioid switching was uncontrolled pain and adverse effects (12 patients). No significant changes between the initial conversion ratio and final conversion ratio between the two opioids were found.

CONCLUSION

Switching from oxycodone to methadone is a reliable method to improve the opioid response in advanced cancer patients. A ratio of 3.3 appears to be reliable, even at high doses. Further studies should be performed to confirm these results in other settings and with very high doses of oxycodone.

Conversion ratios for opioid switching in the treatment of cancer pain: a systematic review

In this paper we describe the results of a systematic search of the literature on conversion ratios during opioid switching. This is part of a project of the European Palliative Care Research Collaboration to update the European Association for Palliative Care recommendations for the use of opioid analgesics in the treatment of cancer pain. Studies were eligible for inclusion if they involved adult patients with chronic cancer pain, contained data on opioid conversion ratios, were prospective and were written in English. Thirty-one studies were identified and included. The majority of the studies had methodological flaws and were not designed to explore or demonstrate equianalgesic dose data. However, the data allow some recommendations to be made that could be helpful to clinicians for whom there are few reliable experimental data on which to base dosing guidelines. Switching to transdermal fentanyl (TDfe) or buprenorphine (TDbu) is an option for patients with stable, controlled pain. Reliable and consistent studies show a ratio of 100 : 1 between oral morphine (ORmo) and TDfe. A ratio of 75 : 1 between ORmo and TDbu may be appropriate, but the supporting evidence here is much less robust. Data are relatively consistent to support a conversion ratio between ORmo and oral hydromorphone (ORhy) of 5 : 1. Despite some limitations, there is evidence to support the use of an approximate conversion ratio of ORmo:oral oxycodone (ORox) of 1.5 : 1. The conversion between ORox and ORhy is estimated to be 1 : 4. When switching from different opioids to methadone the conversion ratio is highly variable, ranging from 5 : 1 to 10 : 1 and much higher in some studies. The derived ratios are influenced by several factors, including the reasons for switching and previous opioid doses. An individual treatment decision and strict monitoring is recommended for patients considered at risk.

Opioid therapy for osteoarthritis and chronic low back pain

BACKGROUND

Chronic low back pain (CLBP) and osteoarthritis (OA) of any joint are highly prevalent, occurring in > 50% of US adults aged ≥ 60 years. Opioids are prescribed more frequently for CLBP and OA than for any other noncancer pain, and the judicious use of opioids is recommended by treatment guidelines for the management of CLBP and OA pain.

OBJECTIVE

To review the appropriate role of opioid analgesics in the treatment of patients with moderate-to-severe pain due to CLBP or OA and provide recommendations for best practices when prescribing opioids.

METHODS

Articles were identified through a search of PubMed. Additional references were identified for inclusion from the reference lists of articles identified via the literature search, treatment guidelines, and Cochrane Reviews.

RESULTS

The available data suggest that opioid therapy represents a valuable treatment option in patients who do not respond to other analgesics and in whom the potential benefits of treatment outweigh the potential risks. Prescribing physicians need to perform vigilant patient screening and monitoring for signs of abuse, intervene promptly to manage or prevent adverse events and drug interactions, tailor opioid therapy to individual patients' comorbidities, and know how to switch or rotate opioids to find the best treatment option.

CONCLUSIONS

Prescribers need to understand the place of opioid therapy in a multimodal treatment program that includes patient rehabilitation to reduce pain and improve function. The analgesic benefits of opioids must be balanced against concerns about addiction and abuse, adverse events, and their potential impact on other aspects of treatment.