Prolonged opioid antagonism with naloxone in chronic renal failure

Opioids for chronic pain management in patients with dialysis-dependent kidney failure

Chronic pain is highly prevalent among adults treated with maintenance haemodialysis (HD) and has profound negative effects. Over four decades, research has demonstrated that 50-80% of adult patients treated with HD report having pain. Half of patients with HD-dependent kidney failure (HDKF) have chronic moderate-to-severe pain, which is similar to the burden of pain in patients with cancer. However, pain management in patients with HDKF is often ineffective as most patients report that their pain is inadequately treated. Opioid analgesics are prescribed more frequently for patients receiving HD than for individuals in the general population with chronic pain, and are associated with increased morbidity, mortality and health-care resource use. Furthermore, current opioid prescribing patterns are frequently inconsistent with guideline-recommended care. Evidence for the effectiveness of opioids in pain management in general, and in patients with HDKF specifically, is lacking. Nonetheless, long-term opioid therapy has a role in the treatment of some patients when used selectively, carefully and combined with an ongoing assessment of risks and benefits. Here, we provide a comprehensive overview of the use of opioid therapy in patients with HDKF and chronic pain, including a discussion of buprenorphine, which has potential as an analgesic option for patients receiving HD owing to its unique pharmacological properties.

Drug Interaction and Serotonin Toxicity with Opioid Use: Another Reason to Avoid Opioids in Headache and Migraine Treatment

Treatment of headache, specifically migraine attacks, has always been a challenging subject, especially for neurologist and pain specialists. Triptans are generally underutilized, despite being the gold standard abortive medication for migraine attacks. On the other hand, opioid analgesics are overused as a treatment for headache. One reason for this could be physician unfamiliarity with drug interactions between opioids and other medications, especially the possibility of serotonin toxicity. The general awareness of potential serotonin toxicity with using opioid analgesics is low. In this review, we will conduct a theoretic and evidence-based review of the potential for developing serotonin syndrome in patients who are using opioids analgesics, especially in combination with antidepressants, a common co-prescribed combination. We also review the current diagnostic criteria for serotonin syndrome and identify possible shortcomings of those criteria. Our aim is to increase the awareness of health care providers about potential drug interaction of opioid analgesics with other classes of medication. We place particular emphasis on tramadol since this drug is one of the most commonly used opioid analgesics for headache. The potential for developing serotonin syndrome is relatively high in the patients who are using opioid for pain control. The use of opioids in migraine headache is already discouraged due to the high risk of medication overuse headache and also an increase in headache-related disability (Katsarava et al. Neurology 62:788-790, 2004; Bigal and Lipton. Neurology 71:1821-8, 2008; Casucci and Cevoli. Neurol Sci. 34 Suppl 1:S125-8, 2013). This is another reason that physicians and health care providers should avoid using this class of medication for pain, specifically headache and migraine treatment.

A systematic review of the use of opioid medication for those with moderate to severe cancer pain and renal impairment: a European Palliative Care Research Collaborative opioid guidelines project

BACKGROUND

Opioid use in patients with renal impairment can lead to increased adverse effects. Opioids differ in their effect in renal impairment in both efficacy and tolerability. This systematic literature review forms the basis of guidelines for opioid use in renal impairment and cancer pain as part of the European Palliative Care Research Collaborative's opioid guidelines project.

OBJECTIVE

The objective of this study was to identify and assess the quality of evidence for the safe and effective use of opioids for the relief of cancer pain in patients with renal impairment and to produce guidelines.

SEARCH STRATEGY

The Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, MedLine, EMBASE and CINAHL were systematically searched in addition to hand searching of relevant journals.

SELECTION CRITERIA

Studies were included if they reported a clinical outcome relevant to the use of selected opioids in cancer-related pain and renal impairment. The selected opioids were morphine, diamorphine, codeine, dextropropoxyphene, dihydrocodeine, oxycodone, hydromorphone, buprenorphine, tramadol, alfentanil, fentanyl, sufentanil, remifentanil, pethidine and methadone. No direct comparator was required for inclusion. Studies assessing the long-term efficacy of opioids during dialysis were excluded.

DATA COLLECTION AND ANALYSIS

This is a narrative systematic review and no meta-analysis was performed. The Grading of RECOMMENDATIONS Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of the studies and to formulate guidelines.

MAIN RESULTS

Fifteen original articles were identified. Eight prospective and seven retrospective clinical studies were identified but no randomized controlled trials. No results were found for diamorphine, codeine, dihydrocodeine, buprenorphine, tramadol, dextropropoxyphene, methadone or remifentanil.

CONCLUSIONS

All of the studies identified have a significant risk of bias inherent in the study methodology and there is additional significant risk of publication bias. Overall evidence is of very low quality. The direct clinical evidence in cancer-related pain and renal impairment is insufficient to allow formulation of guidelines but is suggestive of significant differences in risk between opioids.

RECOMMENDATIONS

RECOMMENDATIONS regarding opioid use in renal impairment and cancer pain are made on the basis of pharmacokinetic data, extrapolation from non-cancer pain studies and from clinical experience. The risk of opioid use in renal impairment is stratified according to the activity of opioid metabolites, potential for accumulation and reports of successful or harmful use. Fentanyl, alfentanil and methadone are identified, with caveats, as the least likely to cause harm when used appropriately. Morphine may be associated with toxicity in patients with renal impairment. Unwanted side effects with morphine may be satisfactorily dealt with by either increasing the dosing interval or reducing the 24 hour dose or by switching to an alternative opioid.

Oral morphine overdose in a cancer patient antagonized by prolonged naloxone infusion

An 80-year-old male was diagnosed with carcinoma in the lung with multiple bony metastases and had been prescribed pain medications as per World Health Organization analgesic ladder guidelines. However, he was not getting adequate pain relief and there were difficulties in titration of the morphine doses on an outpatient basis. Therefore, he was hospitalized for dose titration of oral morphine and was coprescribed amitriptyline and ranitidine. During the titration of the analgesic dose, he developed severe symptoms of morphine overdose. He was immediately treated with intravenous naloxone. After prolonged infusion of naloxone, he achieved his baseline vital parameters without any permanent sequel to the overdose event. This case report describes the possible causes of oral morphine overdose in the elderly and its successful treatment. To prevent such complications, one has to be very cautious of other factors such as drug interactions, particularly in the elderly.

Drug dosing in chronic kidney disease

Patients with chronic kidney disease (CKD) are at high risk for adverse drug reactions and drug-drug interactions. Drug dosing in these patients often proves to be a difficult task. Renal dysfunction-induced changes in human pathophysiology regularly results may alter medication pharmacodynamics and handling. Several pharmacokinetic parameters are adversely affected by CKD, secondary to a reduced oral absorption and glomerular filtration; altered tubular secretion; and reabsorption and changes in intestinal, hepatic, and renal metabolism. In general, drug dosing can be accomplished by multiple methods; however, the most common recommendations are often to reduce the dose or expand the dosing interval, or use both methods simultaneously. Some medications need to be avoided all together in CKD either because of lack of efficacy or increased risk of toxicity. Nevertheless, specific recommendations are available for dosing of certain medications and are an important resource, because most are based on clinical or pharmacokinetic trials.

Transdermal delivery of naloxone: skin permeation, pharmacokinetic, irritancy and stability studies

The current investigation aims to evaluate ex vivo, in vivo performance, stability and irritancy potential of a transdermal formulation of naloxone (NLX) developed at our laboratory at different concentrations (10, 20 and 30mg/g of gel) in a transdermal reservoir patch. Ex vivo permeation studies were performed by employing porcine and rat skins. In vivo performance was assessed in Sprague-Dawley rats by single and multiple application of the patch. Further stability of the formulation was established for 3 months at accelerated stability conditions as per ICH guidelines. Amongst the barriers used the rat skin was found to be more permeable than the porcine epidermis and the flux across each barrier increased with increasing thermodynamic activity of drug in the gel. Based on ex vivo data, the surface area (SA) of the patch was predicted to be 39.6 cm(2) in order to achieve therapeutic blood levels. Upon single dose administration, the steady-state levels were maintained from 4-48 h, which proves the clear advantage of transdermal delivery system over the current mode of administration, i.e., intravenous (i.v.) bolus which is effective upto a maximum of 1.5h. Upon multiple dose administration, the sustained steady state for 12h, even after patch removal proves the formation of drug depot in the skin. The formulations were found to be stable with respect to NLX assay and penetration enhancer efficacy upto 3 months under accelerated stability conditions. The alteration of penetration barrier function, as evidenced by increased trans epidermal water loss (TEWL) was not accompanied by any significant amount of skin irritation measured using laser doppler velocimetry (LDV). The developed transdermal delivery system of NLX is efficacious, stable and safe upon single and multiple dose applications each lasting for 48 h.

Opioids and renal function

Opioids, both endogenous and exogenous, have a strong influence on the renal function through different mechanisms, producing changes in the renal excretion of water and sodium. Several studies have demonstrated that opioids influence renal function, according to the agonist profile used. Mu, kappa, and delta agonists produce different renal effects, although the mechanisms remain unclear. Experimental data have given the input for a possible therapeutic role of kappa agonists for some specific conditions, for example, in treating water retention or hyponatremia occurring in patients who have hepatic cirrhosis with ascites. On the other hand, changes in renal function might strongly condition the use of opioids in the clinical setting, and the knowledge of the relationship between opioids and renal function is mandatory for a tailored approach to accommodate the individual responses in terms of pain intensity, tolerance, and adverse effects experienced by these groups of patients. The influence of renal function when using different opioids in the clinical setting is reviewed, as well as problems related to transplantation, renal damage induced by opioid addiction, and problems related to the use of opioid antagonists in such conditions.

PERSPECTIVE

Endogenous opioids exert physiologic effects on renal function, and the use of opioids may have an influence on renal activity. Renal impairment has a serious impact on the clearance of most opioids used in the clinical setting. Biochemical and clinical monitoring is mandatory to prevent serious complications.