Chronic opioid induced constipation in patients with nonmalignant pain: challenges and opportunities

Update of the Scientific Opinion on opium alkaloids in poppy seeds

Poppy seeds are obtained from the opium poppy (Papaver somniferum L.). They are used as food and to produce edible oil. The opium poppy plant contains narcotic alkaloids such as morphine and codeine. Poppy seeds do not contain the opium alkaloids, but can become contaminated with alkaloids as a result of pest damage and during harvesting. The European Commission asked EFSA to provide an update of the Scientific Opinion on opium alkaloids in poppy seeds. The assessment is based on data on morphine, codeine, thebaine, oripavine, noscapine and papaverine in poppy seed samples. The CONTAM Panel confirms the acute reference dose (ARfD) of 10 μg morphine/kg body weight (bw) and concluded that the concentration of codeine in the poppy seed samples should be taken into account by converting codeine to morphine equivalents, using a factor of 0.2. The ARfD is therefore a group ARfD for morphine and codeine, expressed in morphine equivalents. Mean and high levels of dietary exposure to morphine equivalents from poppy seeds considered to have high levels of opium alkaloids (i.e. poppy seeds from varieties primarily grown for pharmaceutical use) exceed the ARfD in most age groups. For poppy seeds considered to have relatively low concentrations of opium alkaloids (i.e. primarily varieties for food use), some exceedance of the ARfD is also seen at high levels of dietary exposure in most surveys. For noscapine and papaverine, the available data do not allow making a hazard characterisation. However, comparison of the dietary exposure to the recommended therapeutical doses does not suggest a health concern for these alkaloids. For thebaine and oripavine, no risk characterisation was done due to insufficient data. However, for thebaine, limited evidence indicates a higher acute lethality than for morphine and the estimated exposure could present a health risk.

Food pyramid for subjects with chronic pain: foods and dietary constituents as anti-inflammatory and antioxidant agents

Emerging literature suggests that diet constituents may play a modulatory role in chronic pain (CP) through management of inflammation/oxidative stress, resulting in attenuation of pain. We performed a narrative review to evaluate the existing evidence regarding the optimum diet for the management of CP, and we built a food pyramid on this topic. The present review also describes the activities of various natural compounds contained in foods (i.e. phenolic compounds in extra-virgin olive oil (EVO)) listed on our pyramid, which have comparable effects to drug management therapy. This review included 172 eligible studies. The pyramid shows that carbohydrates with low glycaemic index should be consumed every day (three portions), together with fruits and vegetables (five portions), yogurt (125 ml), red wine (125 ml) and EVO; weekly: legumes and fish (four portions); white meat, eggs and fresh cheese (two portions); red or processed meats (once per week); sweets can be consumed occasionally. The food amounts are estimates based on nutritional and practical considerations. At the top of the pyramid there is a pennant: it means that CP subjects may need a specific customised supplementation (vitamin B12, vitamin D, n-3 fatty acids, fibre). The food pyramid proposal will serve to guide dietary intake with to the intent of alleviating pain in CP patients. Moreover, a targeted diet can also help to solve problems related to the drugs used to combat CP, i.e. constipation. However, this paper would be an early hypothetical proposal due to the limitations of the studies.

Cardiovascular Safety of the Selective μ-Opioid Receptor Antagonist Naloxegol: A Novel Therapy for Opioid-Induced Constipation

Background:

Naloxegol is a novel selective, peripherally acting μ-opioid receptor antagonist for treating opioid-induced constipation (OIC) in patients with chronic pain syndromes. We analyzed the cardiovascular (CV) safety of naloxegol based on data from its development program prior to approval by the US Food and Drug Administration in 2015.

Methods:

Comprehensive CV safety analyses were performed in 4 clinical studies of naloxegol (12.5 and/or 25 mg) in patients with noncancer pain and OIC: two 12-week, double-blind, randomized studies; a 12-week, double-blind, extension study; and a 52-week, randomized, open-label study versus usual care. Evaluations of baseline CV risk were obtained from medical histories and clinical findings at the time of study initiation.

Results:

Across the 4 studies (N = 2135), 68% of patients had ≥1 CV risk factor and 41% had a history of CV disease, diabetes, or ≥2 other CV risk factors. There were no increases in blood pressure, heart rate, or the rate-pressure product with naloxegol versus placebo. The rates of major adverse cardiovascular events (MACE) per 100 patient-years of exposure were 1.13 (95% confidence interval [CI], 0.31-2.89) for placebo/usual care and 0.75 (95% CI, 0.24-1.75) for naloxegol. The relative risk of MACE for all doses of naloxegol versus placebo was 0.67 (95% CI, 0.14-3.36).

Conclusion:

These data demonstrate that naloxegol has a CV safety profile comparable to placebo/usual care in patients with OIC. Although the observed number of events was low, the data show no CV signal in patients with OIC treated with naloxegol.

New therapeutic perspectives in irritable bowel syndrome: Targeting low-grade inflammation, immuno-neuroendocrine axis, motility, secretion and beyond

Irritable bowel syndrome (IBS) is a chronic, recurring, and remitting functional disorder of the gastrointestinal tract characterized by abdominal pain, distention, and changes in bowel habits. Although there are several drugs for IBS, effective and approved treatments for one or more of the symptoms for various IBS subtypes are needed. Improved understanding of pathophysiological mechanisms such as the role of impaired bile acid metabolism, neurohormonal regulation, immune dysfunction, the epithelial barrier and the secretory properties of the gut has led to advancements in the treatment of IBS. With regards to therapies for restoring intestinal permeability, multiple studies with prebiotics and probiotics are ongoing, even if to date their efficacy has been limited. In parallel, much progress has been made in targeting low-grade inflammation, especially through the introduction of drugs such as mesalazine and rifaximin, even if a better knowledge of the mechanisms underlying the low-grade inflammation in IBS may allow the design of clinical trials that test the efficacy and safety of such drugs. This literature review aims to summarize the findings related to new and investigational therapeutic agents for IBS, most recently developed in preclinical as well as Phase 1 and Phase 2 clinical studies.

Opioids in Gastroenterology: Treating Adverse Effects and Creating Therapeutic Benefits

The use of opioid medications on both an acute and chronic basis is ubiquitous in the United States. As opioid receptors densely populate the gastrointestinal tract, symptoms and side effects can be expected in these patients. In the esophagus, dysmotility may result, manifesting with dysphagia and a syndrome indistinguishable from primary achalasia. In the stomach, a marked delay in gastric emptying may occur with postprandial nausea and early satiety. Postoperatively, particularly with abdominal surgery, opioid-induced ileus may ensue. In the colon, opioid-induced constipation is common. A unique syndrome termed narcotic bowel syndrome is characterized by chronic abdominal pain often accompanied by nausea and vomiting in the absence of other identifiable causes. With the recognition of the important role of opioids on gastrointestinal function, novel drugs have been developed that use this physiology. These medications include peripheral acting opioid agonists to treat opioid-induced constipation and combination agonist and antagonists used for diarrhea-predominant irritable bowel syndrome. This review summarizes the most recent data in these areas.

Opioid analgesic use among patients presenting with acute abdominal pain and factors associated with surgical diagnoses

BACKGROUND

The prevalence of chronic opioid use among non-cancer patients presenting with acute abdominal pain (AAP) is unknown. The aim was to characterize opioid use, constipation, diagnoses, and risk factors for surgical diagnoses among non-cancer patients presenting with AAP to an emergency department (ED).

METHODS

We performed a retrospective, observational cohort study of all (n=16,121) adult patients (88% from MN, IA and WI) presenting during 2014 with AAP. We used electronic medical records, and focused on 2352 adults with AAP who underwent abdominal CT scan within 24 hours of presentation. We determined odds ratios of association with constipation and features predicting conditions that may require surgery (surgical diagnosis).

KEY RESULTS

There were 2352 eligible patients; 18.8% were opioid users. Constipation was more frequent in opioid (35.1%) compared to non-opioid users [OR 2.88 (95% CI 2.28, 3.62)]. Prevalence of surgical diagnosis in the opioid and non-opioid users was 35.3% and 41.7% respectively (P=.019). By univariate analysis, age and neutrophil count independently predicted increased risk, and chronic opioid use decreased risk of surgical diagnosis. Internal validation of logistic models using a randomly selected validation subset (25% of entire cohort, 587/2352) showed receiver operating characteristic (ROC) curves for the validation and full cohorts were similar.

CONCLUSIONS AND INFERENCES

Approximately 19% of adults presenting with AAP were opioid users; constipation is almost three times as likely in opioid users compared to non-opioid users presenting with AAP. Factors significantly associated with altered risk of surgical diagnoses were age, opioid use, and neutrophil count.

Peripherally acting μ-opioid receptor antagonists as treatment options for constipation in noncancer pain patients on chronic opioid therapy

Opioid-induced constipation (OIC), a prevalent and distressing side effect of opioid therapy, does not reliably respond to treatment with conventional laxatives. OIC can be a treatment-limiting adverse event. Recent advances in medications with peripherally acting μ-opioid receptor antagonists, such as methylnaltrexone, naloxegol, and alvimopan, hold promise for treating OIC and thus extending the benefits of opioid analgesia to more chronic pain patients. Peripherally acting μ-opioid receptor antagonists have been clinically tested to improve bowel symptoms without compromise to pain relief, although there are associated side effects, including abdominal pain. Other treatment options include fixed-dose combination products of oxycodone analgesic together with naloxone.

The efficacy of standard laxative use for the prevention and treatment of opioid induced constipation during oxycodone use: a small Dutch observational pilot study

BACKGROUND

Dutch clinical guidelines recommend that a standard laxative treatment (SLT) should be prescribed concomitantly when starting opioid treatment to prevent opioid-induced constipation (OIC).

METHODS

Clinical evidence for SLT in the treatment of OIC is lacking, therefore an observational pilot study was performed to explore the efficacy and tolerability of SLT on OIC in patients treated with the opioid oxycodone.

RESULTS

Twenty-four patients (58% female, median (range) age 65 (39-92)) were included in this pilot study. The analysis showed that 9 out of 21 patients (43%) were non-responders to SLT. When also taking into consideration patients tending to develop diarrhea 75% of patients are non-responsive to SLT.

CONCLUSION

This pilot study indicates that optimal laxative therapy (SLT) might not be effective and feasible for the prevention and treatment of OIC.

▼Naloxegol for opioid-induced constipation

▼Naloxegol (Moventig-AstraZeneca) is a peripherally acting mu-opioid receptor antagonist licensed for the treatment of opioid-induced constipation in adults who have had an inadequate response to laxative treatment. It was launched in the United Kingdom in October 2015. Here, we review the evidence for naloxegol and consider its place in the management of opioid-induced constipation.

Combining pain therapy with lifestyle: the role of personalized nutrition and nutritional supplements according to the SIMPAR Feed Your Destiny approach

Recently, attention to the lifestyle of patients has been rapidly increasing in the field of pain therapy, particularly with regard to the role of nutrition in pain development and its management. In this review, we summarize the latest findings on the role of nutrition and nutraceuticals, microbiome, obesity, soy, omega-3 fatty acids, and curcumin supplementation as key elements in modulating the efficacy of analgesic treatments, including opioids. These main topics were addressed during the first edition of the Study In Multidisciplinary Pain Research workshop: “FYD (Feed Your Destiny): Fighting Pain”, held on April 7, 2016, in Rome, Italy, which was sponsored by a grant from the Italian Ministry of Instruction on “Nutraceuticals and Innovative Pharmacology”. The take-home message of this workshop was the recognition that patients with chronic pain should undergo nutritional assessment and counseling, which should be initiated at the onset of treatment. Some foods and supplements used in personalized treatment will likely improve clinical outcomes of analgesic therapy and result in considerable improvement of patient compliance and quality of life. From our current perspective, the potential benefit of including nutrition in personalizing pain medicine is formidable and highly promising.

Factors Associated With the Prophylactic Prescription of a Bowel Regimen to Prevent Opioid-Induced Constipation

OBJECTIVE

Identify factors associated with the prophylactic prescription of a bowel regimen with an inpatient opioid prescription.

METHODS

This was a retrospective cohort study from June 1, 2013, to October 31, 2014 of pediatric inpatients prescribed an oral or intravenous opioid on the general medical/surgical floors. We identified patients with or without a prophylactic prescription of a bowel regimen. We obtained patient demographics, prescriber training level and service and used multivariate logistic regression to analyze the factors associated with prophylactic bowel regimen and opioid prescription.

RESULTS

Of the 6682 encounters that met study criteria, only 966 (14.5%) encounters had prophylactic prescriptions. Patient factors associated with prophylactic prescription include increasing age (per year; odds ratio [OR] = 1.06, 95% confidence interval [CI] 1.05-1.07) and sickle cell diagnosis (OR = 3.19, 95% CI 2.08-4.91). Medication factors associated with prophylactic prescription include a scheduled opioid prescription (OR = 1.75, 95% CI 1.46-2.1) and a prescription for oxycodone (OR = 3.59, 95% CI 2.57-5.00) or morphine (OR = 1.84, 95% CI 1.39-2.44), compared with acetaminophen-hydrocodone. Compared with medical providers, surgeons were less likely (OR = 0.43, 95% CI 0.35-0.53) and pain service providers were more likely to prescribe a prophylactic bowel regimen (OR = 4.12, 95% CI 3.13-5.43).

CONCLUSIONS

More than 85% of inpatient opioid prescriptions did not receive a prophylactic bowel regimen. Future research should examine factors (eg, clinical decision support tools) to increase prophylactic prescription of bowel regimens with opioids for populations found to have lower rates.

Constipation in Elderly Patients with Noncancer Pain: Focus on Opioid-Induced Constipation

Constipation is a common and often debilitating condition in the elderly, which may be caused by underlying disease conditions, structural abnormalities in the bowel, and a variety of medications such as anticholinergics, antidepressants, and opiates. In this review, we focus on opioid-induced constipation (OIC), which is often underrecognized and undertreated in the elderly. When opioid therapy is initiated, healthcare providers are encouraged to evaluate risk factors for the development of constipation as part of a thorough patient history. To this end, the patient assessment should include the use of validated instruments, such as the Bristol Stool Scale and Bowel Function Index, to confirm the diagnosis and provide a basis for evaluating treatment outcomes. Healthcare providers should use a stepwise approach to the treatment of OIC in the elderly. Conventional laxatives are a first-line option and considered well tolerated with short-term use as needed; however, evidence is lacking to support their effectiveness in OIC. Moreover, because of the risk of adverse events and other considerations, such as chewing difficulties and swallowing disorders, conventional oral laxatives may be inappropriate for the treatment of OIC in the elderly. Thus, the availability of new pharmacologic agents such as the peripherally acting µ-opioid receptor antagonists methylnaltrexone and naloxegol, which target the underlying causes of OIC, and the secretagogue lubiprostone may provide more effective treatment options for elderly patients with OIC.

New Options in Constipation Management

Constipation is common in the general population and for those on opioids and/or who are suffering from advanced cancer. Self-management consists of dietary changes, exercise, and laxatives. However, responses to self-management efforts are often inadequate to relieve the subjective and objective experience of constipation. Multiple new anti-constipating medications have recently been tested in randomized trials and the following are available commercially: probiotics, prucalopride, lubiprostone, linaclotide, elobixibat, antidepressants, methylnaltrexone, alvimopan, and naloxegol. This review will discuss the evidence-based benefits of these medications and outline an approach to managing constipation.

Switching to low-dose oral prolonged-release oxycodone/naloxone from WHO-Step I drugs in elderly patients with chronic pain at high risk of early opioid discontinuation

PURPOSE

Chronic pain has a high prevalence in the aging population. Strong opioids also should be considered in older people for the treatment of moderate to severe pain or for pain that impairs functioning and the quality of life. This study aimed to assess the efficacy and safety of the direct switch to low-dose strong opioids (World Health Organization-Step III drugs) in elderly, opioid-naive patients.

PATIENTS AND METHODS

This was a single-center, retrospective, observational study in opioid-naive patients aged ≥75 years, with moderate to severe chronic pain (>6-month duration) and constipation, who initiated treatment with prolonged-release oxycodone/naloxone (OXN-PR). Patients were re-evaluated after 15, 30, and 60 days (T60, final observation). Response to treatment was defined as an improvement in pain of ≥30% after 30 days of therapy without worsening of constipation.

RESULTS

One-hundred and eighty-six patients (mean ± SD age 80.7±4.7 years; 64.5% women) with severe chronic pain (mean average pain intensity 7.1±1.0 on the 11-point numerical rating scale) and constipation (mean Bowel Function Index 64.1±24.4; 89.2% of patients on laxatives) were initiated treatment with OXN-PR (mean daily dose 11.3±3.5 mg). OXN-PR reduced pain intensity rapidly and was well tolerated; 63.4% of patients responded to treatment with OXN-PR. At T60 (mean daily OXN-PR dose, 21.5±9.7 mg), the pain intensity was reduced by 66.7%. In addition, bowel function improved (mean decrease of Bowel Function Index from baseline to T60, -28.2, P<0.0001) and the use of laxatives decreased. Already after 15 days and throughout treatment, ~70% of patients perceived their status as much/extremely improved. Only 1.6% of patients discontinued treatment due to adverse events.

CONCLUSION

Low-dose OXN-PR in elderly patients naive to opioids proved to be an effective option for the treatment of moderate to severe chronic pain. Large-scale trials are needed to improve clinical guidance in the assessment and treatment of pain in older people.

Opioid-Induced Constipation Survey in Patients with Chronic Noncancer Pain

Chronic pain patients relying on chronic opioid therapy are often challenged with opioid-induced constipation (OIC), a difficult condition to treat that has a significant psychosocial impact on those who are affected (Bruner et al., J Pain Res, 8, 2015, 289). Unlike other side effects of opioids, OIC does not resolve over time during chronic opioid use, and treatments used for functional constipation often fail to provide adequate symptom relief (Nelson and Camilleri, Therap Adv Gastroenterol, 8, 2015, 206). Estimates of the prevalence of OIC vary. It has been reported that 15% to 90% of opioid users are affected by OIC (Gaertner et al., J Clin Gastroenterol, 49, 2015, 9; Wan et al., Am Health Drug Benefits, 8, 2015, 93; Coyne et al., Clinicoecon Outcomes Res, 6, 2014, 269). In addition, a recent rise in opioid prescriptions by nonpain specialists has contributed to the increase in opioid-related side effects, such as OIC (Nelson and Camilleri, Therap Adv Gastroenterol, 8, 2015, 206; Tuteja et al., Neurogastroenterol Motil, 22, 2010, 424). We conducted a survey on OIC through PainPathways magazine in fall of 2014 and in spring of 2015. Survey results showed the prevalence of depression and the modification of opioid dosage were higher than previously thought. Additionally, we found that discussions with healthcare workers regarding OIC do not take place regularly. Our results re-emphasize the need for a consensus on OIC-specific diagnostic criteria, evidence-based treatment strategies, outcome metrics, and education about OIC for both prescribers and patients to improve clinical outcome as well as patient satisfaction.

Opioid-induced constipation: advances and clinical guidance

Currently opioids are the most frequently used medications for chronic noncancer pain. Opioid-induced constipation is the most common adverse effect associated with prolonged use of opioids, having a major impact on quality of life. There is an increasing need to treat opioid-induced constipation. With the recent approval of medications for the treatment of opioid-induced constipation, there are several therapeutic approaches. This review addresses the clinical presentation and diagnosis of opioid-induced constipation, barriers to its diagnosis, effects of opioids in the gastrointestinal tract, differential tolerance to opiates in different gastrointestinal organs, medications approved and in development for the treatment of opioid-induced constipation, and a proposed clinical management algorithm for treating opioid-induced constipation in patients with noncancer pain.