Opioid withdrawal syndrome after treatment with low-dose extended-release oxycodone and naloxone in a gastric cancer patient with portal vein thrombosis

Analysis of vascular thrombus and clinicopathological factors in prognosis of gastric cancer: A retrospective cohort study

BACKGROUND

Gastric cancer (GC) is one of the most common malignant tumors in the world, and its prognosis is closely related to many factors. In recent years, the incidence of vascular thrombosis in patients with GC has gradually attracted increasing attention, and studies have shown that it may have a significant impact on the survival rate and prognosis of patients. However, the specific mechanism underlying the association between vascular thrombosis and the prognosis of patients with GC remains unclear.

AIM

To analyze the relationships between vascular cancer support and other clinicopathological factors and their influence on the prognosis of patients with GC.

METHODS

This study retrospectively analyzed the clinicopathological data of 621 patients with GC and divided them into a positive group and a negative group according to the presence or absence of a vascular thrombus. The difference in the 5-year cumulative survival rate between the two groups was compared, and the relationships between vascular cancer thrombus and other clinicopathological factors and their influence on the prognosis of patients with GC were analyzed.

RESULTS

Among 621 patients with GC, the incidence of vascular thrombi was 31.7% (197 patients). Binary logistic regression analysis revealed that the degree of tumor differentiation, depth of invasion, and extent of lymph node metastasis were independent influencing factors for the occurrence of vascular thrombi in GC patients (P < 0.01). The trend of the χ 2 test showed that the degree of differentiation, depth of invasion, and extent of lymph node metastasis were linearly correlated with the percentage of vascular thrombi in GC patients (P < 0.01), and the correlation between lymph node metastasis and vascular thrombi was more significant (r = 0.387). Univariate analysis revealed that the 5-year cumulative survival rate of the positive group was significantly lower than that of the negative group (46.7% vs 73.3%, P < 0.01). Multivariate analysis revealed that age, tumor diameter, TNM stage, and vascular thrombus were independent risk factors for the prognosis of GC patients (all P < 0.05). Further stratified analysis revealed that the 5-year cumulative survival rate of stage III GC patients in the thrombolase-positive group was significantly lower than that in the thrombolase-negative group (36.1% vs 51.4%; P < 0.05).

CONCLUSION

Vascular cancer status is an independent risk factor affecting the prognosis of patients with GC. The combination of vascular cancer suppositories and TNM staging can better judge the prognosis of patients with GC and guide more reasonable treatment.

Opioid toxicity after oxycodone/naloxone to oxycodone conversion: case series

Combination preparations of oxycodone/naloxone are marketed to aid in the management of opioid induced bowel dysfunction, with caution advised in prescribing in cases of liver dysfunction.This case series demonstrates four cases of patients with normal liver function tests who developed significant opioid toxicity on conversion from combination oxycodone/naloxone to oxycodone at equivalent doses, necessitating significant dose reduction.In each case, a cause for intra-hepatic shunting such as cirrhosis, porto-systemic collaterals or thrombosis were identified, highlighting these as cautionary features when prescribing combination preparations of oxycodone/naloxone and the possible need for dose reduction if converting to oxycodone.

Treatment of Opioid Withdrawal Syndrome Triggered by Oxycodone/Naloxone with Dexmedetomidine

The combination of oxycodone and naloxone is useful for cancer pain management. Naloxone, as a pure opioid antagonist, cannot be used simultaneously with opioids. However, owing to its low bioavailability, it can be used in an oral composite formulation. We present the case of a 55-year-old man with gastric cancer who experienced severe opioid withdrawal syndrome (OWS) triggered by oxycodone/naloxone that was successfully managed with dexmedetomidine. He had been in a stable condition on intravenous morphine to alleviate cancer pain. Intravenous morphine was switched to oral oxycodone/naloxone for discharge from the hospital. The patient suddenly developed restlessness, heartburn, and violent behavior 30 minutes after taking oxycodone/naloxone. We attempted sedation with midazolam and propofol, but paradoxical agitation and desaturation occurred. Next, we tried dexmedetomidine and the patient showed a decreased heart rate and reduced agitation. The patient was eventually stabilized by increasing the dose of dexmedetomidine. This report informs clinicians of the possibility of OWS when switching from opioids to oxycodone/naloxone, which can be overcome with the appropriate use of sedatives and dexmedetomidine depending on the patient's condition.

Oxycodone/naloxone versus tapentadol in real-world chronic non-cancer pain management: an observational and pharmacogenetic study

Tapentadol (TAP) and oxycodone/naloxone (OXN) potentially offer an improved opioid tolerability. However, real-world studies in chronic non-cancer pain (CNCP) remain scarce. Our aim was to compare effectiveness and security in daily pain practice, together with the influence of pharmacogenetic markers. An observational study was developed with ambulatory test cases under TAP (n = 194) or OXN (n = 175) prescription with controls (prescribed with other opioids (control), n = 216) CNCP patients. Pain intensity and relief, quality of life, morphine equivalent daily doses (MEDD), concomitant analgesic drugs, adverse events (AEs), hospital frequentation and genetic variants of OPRM1 (rs1799971, A118G) and COMT (rs4680, G472A) genes, were analysed. Test CNCP cases evidenced a significantly higher pain relief predictable due to pain intensity and quality of life (R2 = 0.3), in front of controls. Here, OXN achieved the greatest pain relief under a 28% higher MEDD, 8-13% higher use of pregabalin and duloxetine, and 23% more prescription change due to pain, compared to TAP. Whilst, TAP yielded a better tolerability due the lower number of 4 [0-6] AEs/patient, in front of OXN. Furthermore, OXN COMT-AA homozygotes evidenced higher rates of erythema and vomiting, especially in females. CNCP real-world patients achieved higher pain relief than other traditional opioids with a better tolerability for TAP. Further research is necessary to clarify the potential influence of COMT and sex on OXN side-effects.

Oxycodone/naloxone prolonged-release tablets in patients with moderate-to-severe, chronic cancer pain: Challenges in the context of hepatic impairment

Opioids such as oxycodone are recommended in the management of moderate-to-severe, chronic cancer pain. All opioids can potentially cause constipation, which may be a significant barrier to their use. Multiple randomised clinical trials have shown that the use of naloxone as a peripherally acting mu-opioid receptor antagonist, in combination with oxycodone can prevent or reduce opioid-induced constipation while having equivalent analgesic efficacy to oxycodone alone. However, clinical experience has shown that unexpected events may occur in some patients when unrecognized liver impairment is present. We describe the underlying biological reasons and propose simple, but effective steps to avoid this unusual but potentially serious occurrence. In healthy individuals, naloxone undergoes extensive hepatic first pass metabolism resulting in low systemic bioavailability. However, in patients with hepatic impairment, porto-systemic shunting can increase systemic bioavailability of naloxone, potentially compromising the analgesic efficacy of oral naloxone-oxycodone combinations. This reduced first pass effect can occur in a range of settings that may not always be apparent to the treating clinician, including silent cirrhosis, non-cirrhotic portal hypertension and disruption of liver internal vasculature by metastases. Hepatic function test results correlate poorly with presence and extent of liver disease, and are not indicative of porto-systemic shunting. Presence of hepatic impairment should thus be considered when medication-related outcomes with oxycodone-naloxone combination are not as expected, even if liver function test results are normal.

Naldemedine in Japanese patients with opioid-induced constipation and chronic noncancer pain: open-label Phase III studies

Introduction

Naldemedine is a peripherally-acting µ-opioid-receptor antagonist, approved in Japan for opioid-induced constipation (OIC). In two open-label, single-arm, Phase III studies, we evaluated the safety and efficacy of naldemedine in Japanese patients with OIC receiving regular-use opioids (COMPOSE-6) or prolonged-release oxycodone (COMPOSE-7) for chronic noncancer pain.

Methods

Eligible Japanese adults with OIC and chronic noncancer pain received once-daily oral naldemedine 0.2 mg for 48 weeks, irrespective of food intake. Primary end points included measures of treatment-emergent adverse events (TEAEs), pain intensity, and opioid withdrawal. Secondary efficacy end points were evaluated at treatment week 2. Patient Assessment of Constipation Symptoms (PAC-SYM) and Quality of Life (PAC-QOL) scores were evaluated in both 48-week studies.

Results

Of patients enrolled in COMPOSE-6 (N = 43) and COMPOSE-7 (N = 10), TEAEs were reported in 88% (95% CI 74.9–96.1) and 90% (95% CI 55.5–99.7), respectively. The most frequently reported TEAEs, nasopharyngitis and diarrhea, were mostly mild or moderate in severity. Assessments of pain intensity and opioid withdrawal remained stable over the 48-week treatment periods of both studies. The proportion of spontaneous bowel-movement responders at week 2 in COMPOSE-6 was 81.0% (95% CI 65.9–91.4) and 90.0% (95% CI 55.5–99.7) in COMPOSE-7. Significant and sustained improvements in PAC-SYM and PAC-QOL scores were also observed in both studies (all P<0.05).

Conclusion

Side effects that occurred with naldemedine were mostly mild or moderate in severity, and the data suggested that naldemedine can improve bowel function and QOL in Japanese patients with OIC receiving regular-use opioids or prolonged-release oxycodone for chronic noncancer pain.

Spontaneously reported adverse drug events related to tapentadol and oxycodone/naloxone in Australia

Background

The rapid increase in prescribing and use of opioids for noncancer pain has coincided with an increase in opioid-related adverse drug events (ADEs). The objective of our study was to describe ADEs related to tapentadol and oxycodone/naloxone spontaneously reported to the Australian Therapeutic Goods Administration (TGA).

Methods

Public case detail reports for tapentadol (September 2013-March 2017) and oxycodone/naloxone (April 2011-March 2017) were sourced from the TGA. The total number of public case detail reports for tapentadol were 104 and 249 for oxycodone/naloxone. Demographic characteristics of patients, concomitant medications, causality assessment and outcome were described for each opioid according to the Medical Dictionary for Regulatory Activities (MedDRA) system organ class.

Results

The most prevalent ADEs for tapentadol were nervous system disorders (n = 52, 50%), psychiatric (n = 34, 32.7%), gastrointestinal (n = 18, 17.3%), and general disorders and administration site conditions (n = 21, 20.2%). Sixteen (23.2%) of 69 nervous system disorders reaction terms were consistent with serotonin syndrome of which 14 (87.5%) involved documented coadministration with another serotonergic medication. The most prevalent ADEs for oxycodone/naloxone were psychiatric disorders (n = 78, 31.3%), gastrointestinal (n = 73, 29.3%), general disorders and administration site conditions (n = 87, 35%), and nervous system disorders (n = 62, 24.9%). There were 40 (16%) public case detail reports for oxycodone/naloxone with the MedDRA reaction terms 'drug withdrawal syndrome' and 'withdrawal syndrome'.

Conclusion

The profiles of spontaneous ADE reports for tapentadol and oxycodone/naloxone are largely consistent with their premarketing randomized controlled studies and profiles of opioids in general. Further research into the risk of serotonin syndrome with tapentadol use is warranted. The ADEs suggest clinicians should be cautious when switching patients to oxycodone/naloxone from other opioids.

Analgesic effectiveness and tolerability of oral oxycodone/naloxone and pregabalin in patients with lung cancer and neuropathic pain: an observational analysis

INTRODUCTION

Cancer-related pain has a severe negative impact on quality of life. Combination analgesic therapy with oxycodone and pregabalin is effective for treating neuropathic cancer pain. We investigated the efficacy and tolerability of a dose-escalation combination therapy with prolonged-release oxycodone/naloxone (OXN-PR) and pregabalin in patients with non-small-cell lung cancer and severe neuropathic pain.

METHODS

This was a 4-week, open-label, observational study. Patients were treated with OXN-PR and pregabalin. Average pain intensity ([API] measured on a 0-10 numerical rating scale) and neuropathic pain (Douleur Neuropathique 4) were assessed at study entry and at follow-up visits. The primary endpoint was response to treatment, defined as a reduction of API at T28 ≥30% from baseline. Secondary endpoints included other efficacy measures, as well as patient satisfaction and quality of life (Brief Pain Inventory Short Form), Hospital Anxiety and Depression Scale, and Symptom Distress Scale; bowel function was also assessed.

RESULTS

A total of 56 patients were enrolled. API at baseline was 8.0±0.9, and decreased after 4 weeks by 48% (4.2±1.9; P<0.0001 vs baseline); 46 (82.1%) patients responded to treatment. Significant improvements were also reported in number/severity of breakthrough cancer pain episodes (P=0.001), Brief Pain Inventory Short Form (P=0.0002), Symptom Distress Scale (P<0.0001), Hospital Anxiety and Depression Scale depression (P=0.0006) and anxiety (P<0.0001) subscales, and bowel function (P=0.0003). At study end, 37 (66.0%) patients were satisfied/very satisfied with the new analgesic treatment. Combination therapy had a good safety profile.

CONCLUSION

OXN-PR and pregabalin were safe and highly effective in a real-world setting of severe neuropathic cancer pain, with a high rate of satisfaction, without interference on bowel function.

Emerging therapies for patients with symptoms of opioid-induced bowel dysfunction

Opioid-induced bowel dysfunction (OIBD) comprises gastrointestinal (GI) symptoms, including dry mouth, nausea, vomiting, gastric stasis, bloating, abdominal pain, and opioid-induced constipation, which significantly impair patients’ quality of life and may lead to undertreatment of pain. Traditional laxatives are often prescribed for OIBD symptoms, although they display limited efficacy and exert adverse effects. Other strategies include prokinetics and change of opioids or their administration route. However, these approaches do not address underlying causes of OIBD associated with opioid effects on mostly peripheral opioid receptors located in the GI tract. Targeted management of OIBD comprises purely peripherally acting opioid receptor antagonists and a combination of opioid receptor agonist and antagonist. Methylnaltrexone induces laxation in 50%–60% of patients with advanced diseases and OIBD who do not respond to traditional oral laxatives without inducing opioid withdrawal symptoms with similar response (45%–50%) after an oral administration of naloxegol. A combination of prolonged-release oxycodone with prolonged-release naloxone (OXN) in one tablet (a ratio of 2:1) provides analgesia with limited negative effect on the bowel function, as oxycodone displays high oral bioavailability and naloxone demonstrates local antagonist effect on opioid receptors in the GI tract and is totally inactivated in the liver. OXN in daily doses of up to 80 mg/40 mg provides equally effective analgesia with improved bowel function compared to oxycodone administered alone in patients with chronic non-malignant and cancer-related pain. OIBD is a common complication of long-term opioid therapy and may lead to quality of life deterioration and undertreatment of pain. Thus, a complex assessment and management that addresses underlying causes and patomechanisms of OIBD is recommended. Newer strategies comprise methylnaltrexone or OXN administration in the management of OIBD, and OXN may be also considered as a preventive measure of OIBD development in patients who require opioid administration.

Oxycodone/Naloxone: role in chronic pain management, opioid-induced constipation, and abuse deterrence

The use of opioids in the treatment of chronic pain is widespread; the prevalence of specific opioids varies from country to country and depends on product availability, national formulary systems, and provider preferences. Patients often receive opioids for legitimate treatment of pain conditions, but on the opposite side of the spectrum, nonmedical use of opioids is a significant public health concern. Opioids are associated with several side effects, and constipation is the most commonly reported and persistent symptom. Unlike some adverse effects associated with opioid use, tolerance does not develop to constipation. Opioid-induced constipation (OIC) is the most prevalent patient complaint associated with opioid use and has been associated with declines in various quality of life measures. OIC can be extremely difficult for patients to tolerate and may prompt patients to decrease or discontinue opioid treatment. Current management strategies for OIC are often insufficient. A prolonged-release formulation of oxycodone/naloxone (OXN) has been investigated for the treatment of nonmalignant and cancer pain and mitigation of OIC, and evidence is largely favorable. Studies have demonstrated the capability of OXN to alleviate OIC while maintaining pain control comparable to oxycodone-only regimens. There is insufficient evidence for OXN efficacy for patients with mild OIC or patients maintained on high doses of opioids, and use in these populations is controversial. The reduction of costs associated with OIC may provide overall cost effectiveness with OXN. Additionally, the presence of naloxone may deter abuse/misuse by those seeking to misuse the formulation by modes of administration other than oral ingestion. Most studies to date have occurred in European countries, and phase 3 trials continue in the United States. This review will include current therapeutic options for pain and constipation, unique characteristics of OXN, evidence related to use of OXN and its place in therapy, discussion of opioid abuse/misuse, and various abuse-deterrent mechanisms, and areas of continuing research.

New opioids

Despite the skilled use of opioid analgesics, which is crucial to the relief of cancer pain, there is a lack of evidence to support many aspects of current clinical practice. Therefore, there is a significant need for more effective treatment options. New opioids have been marketed in the past years, including hydrocodone and oxymorphone. Moreover, mixed opioids with combined mechanisms of action have been developed; one such agent, tapentadol, is a centrally acting oral analgesic that possesses a combined mechanism of action: μ-opioid receptor activation with norepinephrine reuptake inhibition. Drug development strategies involving naloxone have been initiated to reduce peripheral opioid-related adverse effects. The rationale is based on the local antagonist activity of naloxone in intestinal opioid receptors and the negligible oral bioavailability of naloxone, particularly in a prolonged-release formulation. New delivery systems have been developed to provide rapid analgesia with potent opioid drugs such as fentanyl. Despite the upcoming availability of these new drugs and technologies that will add to existing types of opioid medication, their benefits and liabilities will ultimately need to be determined by the individual physician and individual patient experiencing pain.