Retardiert freigesetztes Naloxon oral: Aufhebung der Obstipation durch orales Morphin ohne Beseitigung der Analgesie

[Incidence of constipation in patients with outpatient opioid therapy]

BACKGROUND

Constipation is a common complication in patients with opioid therapy. Additionally, patient-related risk factors also contribute to the development of constipation and these factors have to be integrated into an individualized treatment plan.

OBJECTIVE

The aim of this study was to assess the incidence of constipation in patients with opioid therapy in an outpatient setting and to analyze the risk factors that contribute to the development of constipation.

MATERIAL AND METHODS

This retrospective cohort study was conducted in two university affiliated outpatient departments at the Charité hospital in Berlin. The trial included all consecutively treated patients with opioid therapy of at least 4 weeks duration. The study was conducted from January 2013 to August 2013. Constipation was defined according to the Rome III criteria.

RESULTS

Out of 1166 screened patients, altogether 171 patients were included with a median duration of opioid therapy of 5 years. The most common diagnoses were back pain, musculoskeletal pain and neuropathic pain. In 14% of the treated patients symptoms of constipation were detected and another 35% needed laxatives for symptom control resulting in an overall incidence of constipation of 49%. The remaining 51% of the patients did not use any laxatives and did not experience symptoms of constipation. Age and dosing of opioid therapy significantly increased the risk of consipation but duration of opioid therapy was not related to the incidence of constipation.

DISCUSSION

The incidence of constipation in this population remains high although a relevant number of patients were intermittently free of symptoms without using laxatives. An individualized therapy plan and patient education seem to be important elements to control opioid-associated constipation.

Naloxone as part of a prolonged release oxycodone/naloxone combination reduces oxycodone-induced slowing of gastrointestinal transit in healthy volunteers

OBJECTIVES

This exploratory study in healthy volunteers investigated the effect of single doses of oxycodone on gastrointestinal (GI) transit time and the degree to which a single dose of naloxone reverses the oxycodone-induced effect.

METHODS

Fifteen healthy male volunteers received: oxycodone 10 and2 0 mg, oxycodone/naloxone 10/5 and 20/10 mg (all as prolonged release tablets) and placebo. Each dose was radiolabelled and administered with a capsule containing radiolabelled resin (surrogate for GI contents).

RESULTS

Scintigraphic analysis showed that 20 mg oxycodone significantly increased colon arrival time (mean 7.19 vs 5.15 h for placebo, p = 0.0159). Mean colon arrival time for oxycodone/naloxone 20/10 mg (5.16 h) was similar to placebo, although the difference between oxycodone/naloxone 20/10 mg versus oxycodone 20 mg was not significant (p = 0.0653). Colonic geometric centre analysis showed a significant increase in mean time for the resin to reach the colon following oxycodone 10 and 20 mg compared with placebo (increases of 5.3 and 8.8 h). There was no significant effect of naloxone at the lower dose; however, oxycodone/naloxone 20/10 mg significantly reduced mean colonic transit time by 2.1 h (p = 0.0376).

CONCLUSION

A single dose of oxycodone 20 mg significantly prolonged GI transit time but this effect was reduced by co-administration of naloxone.

Managing opioid-induced constipation in advanced illness: focus on methylnaltrexone bromide

Constipation is a common symptom in palliative care patients which can generate considerable suffering. There is uncertainty about the choice of treatment options from varying recommendations for management of constipation and a varying clinical practice in palliative care settings. The purpose of the review was to evaluate the current recommendations of therapy guidelines for the management of opioid-induced constipation in palliative care patients with a focus on methylnaltrexone bromide. Recent findings in the literature and related information on the opioid-induced gastrointestinal disorders in patients with advanced illness, as well as information on the opioid-antagonist methylnaltrexone, are discussed. Knowledge of the role of definitions, the causes of constipation and the pathophysiology of opioid-induced constipation must be given high priority in the treatment of patients receiving opioids. Diagnosis and therapy of constipation, therefore, should relate to findings in clinical investigation. Opioid-induced constipation and its adequate treatment is an important issue for patients with advanced illness and also poses therapeutic challenge for clinicians in daily routine. Methylnaltrexone bromide may represent an important therapeutic option for palliative care patients who are suffering from opioid-induced constipation with failure of conventional prophylactic oral laxative treatment.

[Opioids for cancer pain treatment. Efficacy and side effects]

In Germany, about 400,000 people per year are diagnosed with cancer. In the terminal stage of their disease, up to 95% of cancer patients suffer from pain. In earlier stages, this is true for about 50% of patients. It is estimated that 220,000 people in Germany are in need of cancer pain therapy. If the pain therapy is going to be changed, this must be comprehensively discussed with the patient in advance, particularly when strong opioids are used which are mostly indicated in these patients. Opioids are effective and reliable drugs when pain therapy is performed according to the basic principles. It is widely agreed that the WHO analgesic ladder serves as orientation and that the choice of substances must be suited to the cause and pathophysiological type of pain. Even though a variety of other strong opioids is in clinical use, morphine remains the reference substance for efficacy and occurrence of side effects in opioids.

Stark wirksame Opioidanalgetika und Obstipation

In cancer pain therapy treatment with strong opioids is essential. However, it may be accompanied by the occurrence of various adverse effects. The most frequent and persistent side effect in the course of opioid treatment is constipation. It is mainly caused by linkage of the opioid to the peripheral mu-receptors in the bowel and may increase as a result of certain concomitant circumstances, such as poor intake of fluids or electrolyte disorder. Present research indicates that there is a relation between type of opioid and degree of constipation, i.e. treatment with transdermal fentanyl or methadone tends to cause less constipation compared to morphine or hydromorphone. The route of administration of morphine--oral vs. subcutaneous--does not seem to affect the incidence of opioid-induced constipation. Furthermore, prophylaxis and efficient control of opioid-induced constipation still fail to be part of the routine in pain treatment.

Constipation--modern laxative therapy

It is estimated that one third of the population in Western industrial countries suffers from constipation at least from time to time. Constipation may have somatopathic or functional causes. Furthermore, a great number of substances are known to cause medication-induced constipation, i.e. opioid-induced constipation is caused by linkage of the opioid to opioid receptors in the bowel and the central nerve system. Whenever possible, causal therapy should be undertaken. Patients in palliative care mostly suffer from chronic functional constipation. The treatment consists of basic measures and the application of laxatives. According to their mode of action, they are divided into bulk-forming laxatives, osmotic laxatives, stimulant laxatives, lubricating agents and others. Bulk-forming laxatives are not recommended for use in palliative care patients, for such patients are normally not able to take in the required amount of fluids. Osmotic laxatives are divided into (magnesium) salts, saccharine, alcohols and macrogols. Lactulose is the most popular saccharine laxative. Because of its side effects (flatulence, bloating and abdominal cramping), lactulose is not a laxative of our choice; instead, we prefer to give macrogol. Orally administered, macrogol is not metabolised and pH value and bowel flora remain unchanged. Macrogol hydrates hardened stools, increases stool volume, decreases the duration of colon passage and dilates the bowel wall that then triggers the defecation reflex. Even when given for some time, the effectiveness of macrogol will not decrease. Because of its high effectiveness and commonly good tolerance, macrogol has become the laxative of first choice in palliative care patients with all kinds of chronic constipation, if these patients are able to take in the necessary amount of fluids. From the general medical point of view, lubricating agents have become obsolete. In palliative care patients, however, they are still important laxatives for prophylactic treatment or therapy of constipation. Due to clinical experience, in palliative care a laxative ladder has proven successful.

Long-term treatment of cancer pain with transdermal fentanyl

The long-term therapy of 51 patients using transdermal fentanyl was evaluated. The transdermal therapy was performed for 158 days (range, 15-855 days). The need for increasing dosages of transdermal fentanyl was caused by the progression of the underlying cancer disease (mean initial dose, 69.5 micrograms fentanyl/hr; mean final dose, 167.7 micrograms fentanyl/hr). The transdermal system was changed every third day. Application intervals had to be shortened in 23.5% of the patients. Pain reduction was good throughout the study. Severe side effects did not occur. Constipation and the need for laxatives occurred less frequently than with previously administered oral morphine. Skin tolerance of the transdermal system was good. The treatment of cancer pain with transdermal fentanyl can be performed as a long-term therapy and result in good pain relief. Considering its specific pharmacokinetic properties, it is an alternative medication on step III of the World Health Organization's guidelines for cancer pain management.

Direct conversion from oral morphine to transdermal fentanyl: a multicenter study in patients with cancer pain

Direct conversion from oral morphine to transdermal fentanyl with a ratio of oral morphine/transdermal fentanyl (100:1 mg) daily was examined in patients with cancer pain. Patients with a 'stable and low level of cancer pain' receiving a constant dosage of sustained release morphine during a pre-study phase of 6 days were included in the study. Initial fentanyl dosage was calculated by a conversion table. The transdermal system was changed every 72 h and the dosage was adjusted to the needs of the patients according to the VAS scores and the requirement of liquid morphine, which was allowed to achieve sufficient pain relief. Regression analysis at the end of the study revealed a mean morphine/transdermal fentanyl ratio of 70:1. Pain relief during treatment with transdermal fentanyl was identical to sustained release morphine. However, significantly more patients took supplemental medication with liquid morphine during transdermal fentanyl therapy. The number of patients suffering from pain attacks did not increase with transdermal fentanyl. Constipation and medication with laxatives decreased significantly during fentanyl therapy. Other side effects and vital signs were identical. Three patients suffered from a morphine withdrawal syndrome beginning within the first 24 h of transdermal fentanyl therapy. Cutaneous reactions to the patch were rare, mild and transient. Patients and physicians reported satisfaction with the transdermal therapy. 94.7% of the patients chose to continue the transdermal fentanyl therapy at the end of the study due to better performance in comparison to oral morphine. Due to these results an initial conversion from oral morphine to transdermal fentanyl with the ratio of 100:1 is safe and effective.

[Pharmacotherapy of cancer pain : 2. Use of opioids.]

The adequate use of opioids in the treatment of chronic cancer pain requires sound knowledge of selection criteria for the various opioids, the routes of administration, dosages, dosing schemes and possible side effects. Drug selection depends on the intensity of pain rather than on the specific pathophysiology. Mild to moderate pain can often be treated effectively by so-called "weak" opioids. These include codeine, dihydrocodeine and dextropropoxyphene. Non-opioid analgesics, like acetylsalicylic acid or paracetamol can be added according to the "analgesic ladder" proposed by the World Health Organization (WHO). If adequate pain relief is not achieved "strong" opioids are required. The route of administration that is the safest and the least invasive for the patient should be chosen. Non-invasive (oral, rectal, sublingual, transdermal and intranasal) and invasive routes (intravenous, subcutaneous, spinal and epidural) are available (Table 8). Noninvasive routes are preferred, and most patients can be maintained on oral opioids. Alternatively, in some patients pain can be managed by the sublingual (buprenorphine) route. A transdermal preparation exists for fentanyl, but has not yet been approved for the German market. If the oral route cannot be used or if large doses are required, it will be necessary to change to an invasive route. Intravenous bolus injections provide the fastest onset of analgesic action. They are mostly used in very severe pain. Repeated injections can be avoided by using intravenous or subcutaneous infusions. Various types of pumps delivering analgesics at constant basal infusion rates with the option of rescue doses in case of breakthrough pain are available (patient-controlled analgesia=PCA). Opioids frequently used for s. c. infusion are morphine and hydromorphone. Adjuvant drugs (antiemetics, anxiolytics) can be added. Epidural or intrathecal administration of opioids should only be used in intractable pain or if severe side effects, such as sedation and confusion, will arise with systemic opioids. Morphine, hydromorphone, fentanyl and sufentanil have been used, as have other additional compounds (e.g. local anaesthetics, clonidine). Intracerebroventricular application of morphine has been used only occasionally. In all cases, opioids should be given on to a fixed time schedule thereby, preventing pain from recurring. Additional rescue doses (approximately 50% of baseline single dose) are given for break-through pain. The most frequent side effect of opioids is constipation, and the administration of laxatives is often recommended (Table 5). Nausea, vomiting, sedation and confusion mostly occur in the beginning of opioid therapy. In contrast to constipation, tolerance to these effects develops within days or weeks. True dependence or psychological addiction rarely occurs in patients with chronic cancer pain. In most cases, progression of the underlying disease associated with increasing tissue damage and increasing pain is found. Fear of dependence and addiction often contributes to undertreatment of patients suffering from chronic cancer pain.