Opioid-induced constipation

The P2Y1 receptor in the colonic myenteric plexus of rats and its correlation with opioid-induced constipation

This study was designed to explore the expression changes of P2Y1 receptors in the distal colonic myenteric layer of rats. An opioid induced constipation(OIC) rat model was generated by intraperitoneal (i.p) injection of loperamide. At 7 days post-treatment, the model rats were assessed by calculating the fecal water content and the gastrointestinal transit ratio. The immunofluorescence (IF)-based histochemical study was used to observe the distribution of P2Y1 receptors in the distal colonic myenteric plexus. Western blotting (WB) was performed to evaluate the expression changes of P2Y1 proteins in the myenteric layer, and the electrophysiological approaches were carried out to determine the regulatory roles of P2Y1 receptors on distal colonic motor function. IF showed that P2Y1 receptors are co-expressed MOR in the enteric nerve cells of the distal colonic myenteric plexus. Moreover, the WB revealed that the protein levels of P2Y1 were significantly decreased in the distal colonic myenteric layer of OIC rats. In vitro tension experiments exhibited that the P2Y1 receptor antagonist MRS2500 enhanced the spontaneous contraction amplitude, adding EM2 and β-FNA did not have any effect on MRS2500. Therefore, P2Y1 receptor expression could be associated with the occurrence of OIC in this rat model and the regulation of colonic motility by MOR may be related to the release of purine neurotransmitters such as ATP in the colonic nervous system.

Acute Hydronephrosis Secondary to Methadone-Induced Constipation

Opioid-induced constipation is a significant medical problem accounting for over 40% to 60% of patients without cancer receiving opioids. We report a unique case of a 71-year-old male with a history of opioid use disorder now on methadone maintenance presenting with severe opioid-induced constipation and fecal impaction causing extrinsic compression on the right-sided ureter resulting in right hydronephrosis and hydroureter that improved with aggressive bowel regime with the stool softener, laxatives and enemas.

Methadone alone can predispose to hydroureter with hydronephrosis due to external compression from the severe intestinal dilation secondary to opioid-induced constipation.

Opioid Therapy in Cancer Patients and Survivors at Risk of Addiction, Misuse or Complex Dependency

A clinical conundrum can occur when a patient with active opioid use disorder (OUD) or at elevated risk for the condition presents with cancer and related painful symptoms. Despite earlier beliefs that cancer patients were relatively unaffected by opioid misuse, it appears that cancer patients have similar risks as the general population for OUD but are more likely to need and take opioids. Treating such patients requires an individualized approach, informed consent, and a shared decision-making model. Tools exist to help stratify patients for risk of OUD. While improved clinician education in pain control is needed, patients too need to be better informed about the risks and benefits of opioids. Patients may fear pain more than OUD, but opioids are not always the most effective pain reliever for a given patient and some patients do not tolerate or want to take opioids. The association of OUD with mental health disorders (dual diagnosis) can also complicate delivery of care as patients with mental health issues may be less adherent to treatment and may use opioids for “chemical coping” as much as for pain control.

Papaver Plants: Current Insights on Phytochemical and Nutritional Composition Along with Biotechnological Applications

The genus Papaver is highly esteemed in the pharmacy industry, in the culinary field, and as ornamental plants. These plants are also valued in traditional medicine. Among all Papaver species, Papaver somniferum L. (opium poppy) is the most important species in supplying phytochemicals for the formulation of drugs, mainly alkaloids like morphine, codeine, rhoeadine, thebaine, and papaverine. In addition, Papaver plants present other types of phytochemicals, which altogether are responsible for its biological activities. Therefore, this review covers the phytochemical composition of Papaver plants, including alkaloids, phenolic compounds, and essential oils. The traditional uses are reviewed along with their pharmacological activities. Moreover, safety aspects are reported to provide a deep overview of the pharmacology potential of this genus. An updated search was carried out in databases such as Google Scholar, ScienceDirect, and PubMed to retrieve the information. Overall, this genus is a rich source of alkaloids of different types and also contains interesting phenolic compounds, such as anthocyanins, flavonols, and the characteristic indole derivatives nudicaulins. Among other pharmacological properties, numerous preclinical studies have been published about the analgesic, anticancer, antimicrobial, antioxidant, and antidiabetic activities of Papaver plants. Although it highlights the significant impact of this genus for the treatment of a variety of diseases and conditions, as a future prospect, characterization works accompanying preclinical studies are required along with clinical and toxicology studies to establish a correlation between the scientific and traditional knowledge.

Neurogenic Bowel in Acute Rehabilitation Following Spinal Cord Injury: Impact of Laxatives and Opioids

Objective: To explore the association between bowel dysfunction and use of laxatives and opioids in an acute rehabilitation setting following spinal cord injury (SCI). Methods: Data was collected regarding individuals with acute traumatic/non-traumatic SCI over a two-year period (2012–2013) during both the week of admission and discharge of their inpatient stay. Results: An increase in frequency of bowel movement (BM) (p = 0.003) and a decrease in frequency of fecal incontinence (FI) per week (p < 0.001) between admission and discharge was found across all participants. There was a reduction in the number of individuals using laxatives (p = 0.004) as well as the number of unique laxatives taken (p < 0.001) between admission and discharge in our cohort. The number of individuals using opioids and the average dose of opioids in morphine milligram equivalents (MME) from admission to discharge were significantly reduced (p = 0.001 and p = 0.02, respectively). There was a positive correlation between the number of laxatives and frequency of FI at discharge (r = 0.194, p = 0.014), suggesting that an increase in laxative use results in an increased frequency of FI. Finally, there was a significant negative correlation between average dose of opioids (MME) and frequency of BM at discharge, confirming the constipating effect of opioids (r = −0.20, p = 0.009).

Central and peripheral modulation of gastrointestinal transit in mice by DN-9, a multifunctional opioid/NPFF receptor agonist

BACKGROUND

The nonapeptide DN-9 functions as a multifunctional agonist to opioid and neuropeptide FF (NPFF) receptors and exhibits antinociceptive effects at the central and peripheral levels.

METHODS

The effects of DN-9 on small and colonic intestinal transit were evaluated using the upper gastrointestinal (GI) transit test and colonic bead expulsion assay, respectively. Opioid and NPFF receptor antagonists were used to investigate the mechanisms of DN-9-induced GI inhibition. Furthermore, the agonism of the DN-9 analog [Phg⁹ ]-DN-9 to opioid and NPFF receptors was tested by the cAMP assay.

KEY RESULTS

Intracerebroventricular administration of DN-9 dose-dependently slowed upper GI transit and colonic expulsion via mu- and kappa-opioid receptors in the brain, independent of the delta-opioid receptor. Similarly, intraperitoneal injection of DN-9 dose-dependently inhibited GI propulsion via the peripheral opioid receptors. DN-9-induced GI transit inhibitions were significantly aggravated by the NPFF receptor antagonist RF9. Moreover, the DN-9 analog [Phg⁹ ]-DN-9, an agonist at mu-, delta-, and kappa-opioid receptors but not NPFF receptors, inhibited GI more potently than DN-9. In addition, intracerebroventricular NPFF significantly attenuated the central inhibitory effects induced by [Phg⁹ ]-DN-9 and morphine. However, central and peripheral injections of NPFF or RF9 almost had no significant effects on GI transit by itself.

CONCLUSION AND INFERENCES

Intracerebroventricular and intraperitoneal administrations of DN-9 inhibit GI transit via opioid receptors in mice by central and peripheral mechanisms, respectively. In addition, the NPFF agonism of DN-9 possesses antiopioid effects on GI transit, which might explain the reduced constipation at the antinociceptive doses.

Effect of an electronic medical record design modification on laxative co-prescribing among hospitalised patients taking opioids: A before-and-after study

CONTEXT

Constipation occurs in up to 71.7% (33/46) of hospital inpatients taking opioid analgesics. Co-prescribing laxatives with opioid analgesics is recommended to prevent opioid-induced constipation.

OBJECTIVES

This study aimed to examine the effect of an electronic medical record (EMR) design modification to increase laxative co-prescribing among hospitalised inpatients taking opioid analgesics.

METHODS

In this retrospective 3-month before-and-after study, an EMR modification to improve docusate with sennosides order sentence visibility was implemented on 21 February 2018, at a teaching hospital in Sydney, Australia. The primary outcome was the co-prescription rate of docusate with sennosides within 24-h of the first opioid analgesic administered. International Classification of Diseases 10th Revision Australian Modification diagnosis codes were collected from the EMR. Multivariable logistic regression was performed to determine the impact of the EMR modification on co-prescribing of laxatives with opioid analgesics.

RESULTS

Of the 1832 adult inpatients included in the study (51.0% male), 50.5% were admitted before the EMR modification implementation and 49.5% were admitted afterwards. Docusate with sennosides was co-prescribed in 12.5% of patients before and 14.9% of patients after the EMR modification. Although the EMR modification did not change laxative co-prescribing among surgical patients (odds ratio [OR] = 1.1, 95% confidence interval [CI] 0.8-1.6, p = 0.54), a significant increase in co-prescription of docusate with sennosides among aged care patients (OR = 1.8, 95% CI 1.0-3.0, p = 0.03) was observed.

CONCLUSIONS

An EMR design modification did not change laxative co-prescribing in hospital inpatients overall. However, the EMR modification was associated with a significant increase in laxative co-prescribing among aged care patients prescribed opioid analgesics.

Patients' Self-Assessment of the Symptoms and Impact of Opioid-Induced Constipation: Results From a Prospective Observational Cohort Study of Japanese Patients With Cancer

CONTEXT

Many patients who have cancer consider opioid-induced constipation (OIC) to be a burdensome side effect of opioid treatment.

OBJECTIVES

To evaluate patient-reported outcomes in Japanese patients with cancer pain and OIC.

METHODS

This prospective observational study evaluated OIC incidence for two weeks in patients with cancer after they initiated strong opioid therapy. Rome IV diagnostic criteria, a physician's diagnosis, spontaneous bowel movements, Bowel Function Index score, and patients' daily self-assessments were used. Changes from baseline in Patient Assessment of Constipation Symptoms and Patient Assessment of Constipation Quality of Life (PAC-QOL) scores were compared between patients with and without OIC. Patients and health care providers (HCPs) completed study-specific questionnaires regarding OIC burden, treatment satisfaction, and patient-provider communications.

RESULTS

Among 212 enrolled patients, the incidence of OIC was 47.6% by patients' self-assessments, with a cumulative incidence of 30.2% by Day 3 and 43.5% by Day 7. Patient Assessment of Constipation Symptoms and PAC-QOL overall scores from patients with OIC worsened significantly from baseline compared with patients without OIC by all diagnostic criteria, except for spontaneous bowel movement frequency for PAC-QOL. Patients and HCPs were generally satisfied with OIC treatment; however, 53.5% of patients and approximately 40.0% of HCPs reported that OIC affected pain management. Most patients and HCPs reported that OIC conditions were sufficiently or essentially communicated.

CONCLUSION

After starting opioid therapy, patients recognized OIC onset and its impact on cancer pain management, highlighting the need for effective patient-provider communications, diagnosis, and treatment of OIC to improve QOL for patients with cancer receiving opioid analgesics.

Rates of appropriate laxative prophylaxis for opioid-induced constipation in veterans with lung cancer: a retrospective cohort study

PURPOSE

Opioid-induced constipation (OIC) is the most common side effect in patient-prescribed opioids for cancer pain treatment. Current guidelines recommend routine prescription of a laxative for preventing OIC in all patients prescribed an opioid unless a contraindication exists. We determined patterns of prescription of laxative agents in patients with lung cancer initiating opioids.

METHODS

We performed a retrospective cohort study evaluating the prescription of laxatives for OIC to adult patients with incident lung cancer seen in the Veteran's Affairs (VA) system, between January 1, 2003, and December 31, 2016. Exposure to laxative agents was categorized as follows: none, docusate monotherapy, docusate plus another laxative, and other laxatives only. Prevalence of OIC prophylaxis was analyzed using descriptive statistics. Linear regression was performed to identify time trends in the prescription of OIC prophylaxis.

RESULTS

Overall, 130,990 individuals were included in the analysis. Of these, 87% of patients received inadequate prophylaxis (75% no prophylaxis and 12% docusate alone), while 5% received OIC prophylaxis with the unnecessary addition of docusate to another laxative. Through the study period, laxative prescription significantly decreased, while all other categories of OIC prophylaxis were unchanged. We noted an inverse relationship with OIC prophylaxis and likelihood of a diagnosis of constipation at 3 and 6 months.

CONCLUSIONS

In this study of veterans with lung cancer, almost 90% received inadequate or inappropriate OIC prophylaxis. Efforts to educate physicians and patients to promote appropriate OIC prophylaxis in combination with systems-level changes are warranted.

Sacral nerve stimulation with appropriate parameters improves constipation in rats by enhancing colon motility mediated via the autonomic-cholinergic mechanisms

Although sacral nerve stimulation (SNS) has been applied for treating constipation, its parameters were adopted from SNS for fecal incontinence, its effects are limited, and mechanisms are largely unknown. We investigated the effects and mechanism of SNS with appropriate parameters on constipation in rats treated with loperamide. First, using rectal compliance as an outcome measure, an experiment was performed to derive effective SNS parameters. Then, a 7-day SNS was performed in rats with constipation induced by loperamide. Autonomic functions were assessed by spectral analysis of heart rate variability (HRV) derived from an electrocardiogram. Serum levels of pancreatic polypeptide (PP), norepinephrine (NE), and acetylcholine (ACh) in colon were assessed. 1) Acute SNS at 5 Hz, 100 µs was found effective in enhancing rectal compliance and accelerating distal colon transit (P < 0.05 vs. sham SNS). 2) The 7-day SNS normalized loperamide-induced constipation, assessed by the number, weight, and water content of fecal pellets, and accelerated the distal colon transit (29.4 ± 3.7 min with sham SNS vs. 16.4 ± 5.3 min with SNS but not gastric emptying or intestinal transit. 3) SNS significantly increased vagal activity (P = 0.035) and decreased sympathetic activity (P = 0.012), assessed by spectral analysis of HRV as well as by the serum PP. 4) SNS increased ACh in the colon tissue; atropine blocked the accelerative effect of SNS on distal colon transit. We concluded that SNS with appropriate parameters improves constipation induced by loperamide by accelerating distal colon motility, mediated via the autonomic-cholinergic function.NEW & NOTEWORTHY Although sacral nerve stimulation (SNS) has been applied for treating constipation, its parameters were adopted from SNS for fecal incontinence, effects are limited, and mechanisms are largely unknown. This paper shows that SNS with appropriate parameters improves constipation induced by loperamide by accelerating distal colon motility mediated via the autonomic-cholinergic function.

Opioid-induced constipation: a narrative review of therapeutic options in clinical management

Pain therapy often entails gastrointestinal adverse events. While opioids are effective drugs for pain relief, the incidence of opioid-induced constipation (OIC) varies greatly from 15% to as high as 81%. This can lead to a significant impairment in quality of life, often resulting in discontinuation of opioid therapy. In this regard, a good doctor-patient relationship is especially pivotal when initiating opioid therapy. In addition to a detailed history of bowel habits, patient education regarding the possible gastrointestinal side effects of the drugs is crucial. In addition, the bowel function must be regularly evaluated for the entire duration of treatment with opioids. Furthermore, if the patient has preexisting constipation that is well under control, continuation of that treatment is important. In the absence of such history, general recommendations should include sufficient fluid intake, physical activity, and regular intake of dietary fiber. In patients of OIC with ongoing opioid therapy, the necessity of opioid use should be critically reevaluated in terms of an with acceptable quality of life, particularly in cases of non-cancer pain. If opioids must be continued, lowering the dose may help, as well as changing the type of opioid. If these measures do not suffice, the next step for persistent OIC is the administration of laxatives. If these are ineffective as well, treatment with peripherally active μ-opioid receptor antagonists should be considered. Enemas and irrigation are emergency measures, often used as a last resort.

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.

Drugs for Treating Opioid-Induced Constipation: A Mixed Treatment Comparison Network Meta-analysis of Randomized Controlled Clinical Trials

CONTEXT

Opioid-induced constipation is a common problem associated with chronic use of opioid analgesics.

OBJECTIVES

The objective of this study was to compare available interventions for the treatment of opioid-induced constipation, using principles of network meta-analysis.

METHODS

Electronic databases were searched for randomized controlled clinical trials evaluating drugs used in opioid-induced constipation. Number of patients with rescue-free bowel movements (RFBM) was the primary outcome, and time for achieving RFBM, adverse events, and changes in the analgesic activity of the opioid analgesics were the secondary outcomes. Inverse variance heterogeneity model was used for direct and mixed treatment comparison analysis. Odds ratio for categorical outcomes and weighted mean difference for numerical outcomes were the effect estimates.

RESULTS

We included a total of 23 studies in the systematic review and 21 in the network meta-analysis. Lubriprostone, prucalopride, naldemedine, naloxegol, alvimopan, subcutaneous, and oral methyl naltrexone were observed to perform better than placebo in terms of RFBM. Additionally, subcutaneous methyl naltrexone was significantly better than lubiprostone, naloxegol, oral methyl naltrexone, and prucalopride. Lubiprostone and naldemedine were associated with increased risks of adverse events. Subcutaneous methyl naltrexone did not significantly affect the analgesia due to background opioid use. Quality of evidence for the comparisons is either low or very low.

CONCLUSION

Subcutaneous methyl naltrexone was found to perform better than other interventions for managing opioid-induced constipation.

Mashiningan Improves Opioid-Induced Constipation in Rats by Activating Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channel

Opioid receptor stimulants are analgesics used in patients with and without cancer; however, they often cause constipation, resulting in poor adherence and deterioration of the quality of life. Hence, suitable treatments for constipation are required. In this study, we investigated the pharmacological mechanisms of action of mashiningan (MNG), a Kampo medicine used to treat constipation, and evaluated the effect of MNG on opioid-induced constipation in rats. MNG (100 or 300 mg/kg) was orally administered to normal or codeine phosphate (CPH)-induced constipation in rats, and its effect was evaluated on the basis of fecal counts, characteristics, and weight. Small intestinal fluid secretion was measured after treatment with MNG alone or coadministration with a cystic fibrosis transmembrane conductance regulator (CFTR)-specific inhibitor (CFTRinh-172). The effects of MNG on the CFTR and type-2 chloride channel were determined using patch-clamp or short-circuit current experiments, respectively. MNG increased the fecal weight and proportion of soft feces in normal rats. CPH-induced constipation in rats decreased fecal counts and weight, whereas MNG prevented these effects and increased the proportion of soft feces. MNG increased the electronic chloride current, and this effect was inhibited by the CFTRinh-172 in the CFTR assay. Furthermore, MNG increased small intestinal fluid secretion, and this effect was abolished by coadministration with the CFTRinh-172. MNG improved opioid-induced constipation in rats, and this improvement may have been mediated by increasing intestinal fluid secretion via CFTR chloride channel activation. Therefore, MNG is expected as a medicine of the treatment of constipation in patients taking opioids.

Laxative effects of Liriope platyphylla are tightly correlated with suppression of endoplasmic reticulum stress in loperamide-induced constipation of SD rats

A dysfunction of endoplasmic reticulum (ER) stress response can result in various diseases, including cancer, inflammation, diabetes and neurodegenerative disorders. To investigate whether ER stress response can play an essential role in the induction and treatment of chronic constipation, alterations in the key parameters for ER stress were measured in loperamide (Lop) induced constipation Sprague Dawley (SD) rats treated with aqueous extracts of Liriope platyphylla (AEtLP), which has been shown to have a laxative effect. Symptoms of chronic constipation including alteration of stool parameters and the transverse colon's structure were successfully induced by Lop treatment. Laxative effects such as enhancement of stools parameters, recovery of the mucosa thickness, increased muscle thickness and recovery of flat luminal surface were also observed in the Lop+AEtLP treated group. Furthermore, enhancement of eukaryotic initiation factor 2 alpha (eIF2α) phosphorylation and inositol-requiring enzyme 1 beta (IRE1β) expression, key indicators for ER stress, that were observed in the Lop+vehicle treated group were significantly recovered in the Lop+AEtLP treated group, although the phosphorylation level of c-Jun N-terminal protein kinase (JNK) remained constant. Moreover, alterations in the transcription level of the marker genes X-box binding protein 1 (XBP-1) and growth arrest and DNA damage-inducible protein (GADD34) were similar to those of eIF2α and IRE1β. However, their level was slightly or completely recovered after AEtLP treatment. Overall, this study provides the first evidence that ER stress response may be tightly correlated with chronic constipation induced by Lop treatment, as well as the laxative effects of AEtLP.

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.

Switching off pain at the source: is this the end for opioid pain relief?

Opiates, like morphine or codeine, are used to suppress nociceptive pain in humans. While these drugs can provide effective pain relief, they also cause an extensive array of undesirable side effects, including central depression, sedation and addiction. Relatively recently, the sodium channel Nav1.7 was shown to be essential for pain perception in humans. Based on this, we describe a new technical approach that may be useful for the prolonged suppression of nociceptive pain. The technique uses a harmless adeno-associated virus carrying a short hairpin RNA to silence Nav1.7 ion channels only in sensory neurons underlying pain perception. The major advantage is that pain may be suppressed at the source for many months, without the side effects of opiates.