Potential uses of topical opioids in palliative care--report of 6 cases

Topical Morphine Gel as a Systemic Opioid Sparing Technique

Use of topical morphine gel was explored retrospectively for treatment of painful chronic wounds in hospitalized adults. Systemic opioid use and pain intensity were characterized before and after morphine gel initiation using morphine equivalent daily dose (MEDD) and the Defense and Veterans Pain Rating Scale (DVPRS) score at 24 hours before compared to 24 hours, 48 hours, and one week after morphine gel initiation. Twenty-three patients received 371 applications of topical morphine gel. The median number of applications received was 8.0 [5.0 to 26.0] per patient. Median change in MEDD 24 hours after morphine gel initiation was 0.0 mg [-15.3 to 11.3] (n = 21), 48 hours after was -4.4 mg [-27.5 to 8.8] (n = 20), and one week after was -7.5 mg [-41.9 to -0.3] (n = 12). Median change in DVPRS score 24 hours after morphine gel initiation was 0.0 [-0.5 to 1.5] (n = 13), 48 hours after was -0.5 [-3.25 to 0.0] (n = 14), and one week after was 1.0 [-1.0 to 3.5] (n = 9). In this single-center analysis, patients with painful chronic wounds treated with morphine gel required lower doses of systemic opioids. Topical morphine gel may provide analgesia while sparing systemic opioid use.

Scoping Review of Off-Label Topical Analgesia in Palliative, Hospice and Cancer Care: Towards Flexibility in Evidence-Based Medicine

Purpose

Scoping reviews address the nature of the literature per se rather than inferring evidence-based treatment guidelines. Scoping reviews of the published literature are intended to describe the aggregated nature of the evidence surrounding some agent or intervention, in contrast to systematic reviews that seek when possible to guide clinical practice. We conducted a scoping review to identify reports of potential clinical utility of off-label topical analgesics and adjuvants when FDA-approved treatments have proven inadequate.

Methods

We performed a comprehensive search of three databases (PubMed, Web of Science and Embase) for articles dating from 1947 to the present. Mindful that FDA-approved and WHO-recommended analgesic medications often prove inadequate for individual patients in extremis with palliative, hospice or cancer pain, we used broad, structured inclusion criteria to retrieve articles.

Results

We retrieved 12,100 articles; after screening, we had 39 reports addressing 19 different topical agents out of the 32 chemical entities. Our scoping review disclosed evidence about agents that might not have met inclusion criteria for clinical practice guidelines.

Discussion

Although generally considered lower quality evidence, case reports or series present suggestions for diverse topical medications to manage pain in challenging circumstances when high-quality evidence for agents and routes of administration is lacking.

Conclusion

Patients with the greatest need for evidence to identify and guide lesser-used agents during aggressive pain management are the most difficult to enroll and follow in standardized, controlled and/or blinded clinical trials. This scoping review identifies medications, dosages, and routes of topical agents reported to be effective in these often-challenging circumstances. Until larger and higher quality studies are completed, we must rely on the best available evidence even if of lower quality.

Topical Treatments and Their Molecular/Cellular Mechanisms in Patients with Peripheral Neuropathic Pain-Narrative Review

Neuropathic pain in humans results from an injury or disease of the somatosensory nervous system at the peripheral or central level. Despite the considerable progress in pain management methods made to date, peripheral neuropathic pain significantly impacts patients' quality of life, as pharmacological and non-pharmacological methods often fail or induce side effects. Topical treatments are gaining popularity in the management of peripheral neuropathic pain, due to excellent safety profiles and preferences. Moreover, topical treatments applied locally may target the underlying mechanisms of peripheral sensitization and pain. Recent studies showed that peripheral sensitization results from interactions between neuronal and non-neuronal cells, with numerous signaling molecules and molecular/cellular targets involved. This narrative review discusses the molecular/cellular mechanisms of drugs available in topical formulations utilized in clinical practice and their effectiveness in clinical studies in patients with peripheral neuropathic pain. We searched PubMed for papers published from 1 January 1995 to 30 November 2020. The key search phrases for identifying potentially relevant articles were "topical AND pain", "topical AND neuropathic", "topical AND treatment", "topical AND mechanism", "peripheral neuropathic", and "mechanism". The result of our search was 23 randomized controlled trials (RCT), 9 open-label studies, 16 retrospective studies, 20 case (series) reports, 8 systematic reviews, 66 narrative reviews, and 140 experimental studies. The data from preclinical studies revealed that active compounds of topical treatments exert multiple mechanisms of action, directly or indirectly modulating ion channels, receptors, proteins, and enzymes expressed by neuronal and non-neuronal cells, and thus contributing to antinociception. However, which mechanisms and the extent to which the mechanisms contribute to pain relief observed in humans remain unclear. The evidence from RCTs and reviews supports 5% lidocaine patches, 8% capsaicin patches, and botulinum toxin A injections as effective treatments in patients with peripheral neuropathic pain. In turn, single RCTs support evidence of doxepin, funapide, diclofenac, baclofen, clonidine, loperamide, and cannabidiol in neuropathic pain states. Topical administration of phenytoin, ambroxol, and prazosin is supported by observational clinical studies. For topical amitriptyline, menthol, and gabapentin, evidence comes from case reports and case series. For topical ketamine and baclofen, data supporting their effectiveness are provided by both single RCTs and case series. The discussed data from clinical studies and observations support the usefulness of topical treatments in neuropathic pain management. This review may help clinicians in making decisions regarding whether and which topical treatment may be a beneficial option, particularly in frail patients not tolerating systemic pharmacotherapy.

Systematic review of antimicrobials, mucosal coating agents, anesthetics, and analgesics for the management of oral mucositis in cancer patients and clinical practice guidelines

PURPOSE

To update the clinical practice guidelines for the use of antimicrobials, mucosal coating agents, anesthetics, and analgesics for the prevention and/or treatment of oral mucositis (OM).

METHODS

A systematic review was conducted by the Mucositis Study Group of the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO). The body of evidence for each intervention, in each cancer treatment setting, was assigned an evidence level. The findings were added to the database used to develop the 2014 MASCC/ISOO clinical practice guidelines. Based on the evidence level, the following guidelines were determined: Recommendation, Suggestion, and No Guideline Possible.

RESULTS

A total of 9 new papers were identified within the scope of this section, adding to the 62 papers reviewed in this section previously. A new Suggestion was made for topical 0.2% morphine for the treatment of OM-associated pain in head and neck (H&N) cancer patients treated with RT-CT (modification of previous guideline). A previous Recommendation against the use of sucralfate-combined systemic and topical formulation in the prevention of OM in solid cancer treatment with CT was changed from Recommendation Against to No Guideline Possible. Suggestion for doxepin and fentanyl for the treatment of mucositis-associated pain in H&N cancer patients was changed to No Guideline Possible.

CONCLUSIONS

Of the agents studied for the management of OM in this paper, the evidence supports a Suggestion in favor of topical morphine 0.2% in H&N cancer patients treated with RT-CT for the treatment of OM-associated pain.

Management of Malignant Rectal Pain and Tenesmus: A Systematic Review

Background: Malignant rectal pain (MRP) and tenesmus cause significant morbidity for cancer patients at all stages of disease. There is little evidence to guide management of these symptoms. Objective: The objective of this review was to summarize the existing evidence base for palliative management of MRP and tenesmus outside of standard oncologic or surgical management. Design: A systematic review of PubMed and Embase was conducted according to PRISMA guidelines using preselected search terms for publications between 1980 and January 2017. Setting/Subjects: Studies that described management for patients with tenesmoid pain from malignant tumors of the rectum, anus, or perineum were identified. Measurements: The primary outcome was response of pain to treatment. Results: The search produced 1412 titles. Twenty articles met criteria for inclusion in the review, including 11 case series and 9 case reports. A variety of treatments were found with most patients receiving interventional procedures, but overall evidence to support any particular intervention is limited and of poor quality. Conclusions: This review highlights the limited current evidence base for medical and interventional treatments for MRP and tenesmus. Further study is needed to clarify the best approach to managing these challenging symptoms.

Transdermal and Topical Drug Administration in the Treatment of Pain

The comprehensive treatment of pain is multidimodal, with pharmacotherapy playing a key role. An effective therapy for pain depends on the intensity and type of pain, the patients' age, comorbidities, and appropriate choice of analgesic, its dose and route of administration. This review is aimed at presenting current knowledge on analgesics administered by transdermal and topical routes for physicians, nurses, pharmacists, and other health care professionals dealing with patients suffering from pain. Analgesics administered transdermally or topically act through different mechanisms. Opioids administered transdermally are absorbed into vessels located in subcutaneous tissue and, subsequently, are conveyed in the blood to opioid receptors localized in the central and peripheral nervous system. Non-steroidal anti-inflammatory drugs (NSAIDs) applied topically render analgesia mainly through a high concentration in the structures of the joint and a provision of local anti-inflammatory effects. Topically administered drugs such as lidocaine and capsaicin in patches, capsaicin in cream, EMLA cream, and creams containing antidepressants (i.e., doxepin, amitriptyline) act mainly locally in tissues through receptors and/or ion channels. Transdermal and topical routes offer some advantages over systemic analgesic administration. Analgesics administered topically have a much better profile for adverse effects as they relieve local pain with minimal systemic effects. The transdermal route apart from the above-mentioned advantages and provision of long period of analgesia may be more convenient, especially for patients who are unable to take drugs orally. Topically and transdermally administered opioids are characterised by a lower risk of addiction compared to oral and parenteral routes.

Provider Perspectives on Topical Analgesics

Topical analgesics are effective and alternative means to systemic therapy, often minimizing the adverse drug effects and complications of systemic analgesic use. Despite the number of available topical analgesics, there is little direction provided in practice guidelines on their appropriate use and little is known about patterns of their prescribing. To begin understanding these knowledge gaps, we sought provider perspectives on topical analgesic use at a large academic medical center. This electronic survey seeks to explore the perceptions and prescription patterns of topical analgesics among prescribers in a large academic medical center, where the availability of topical analgesics varies. Among topical analgesics, lidocaine (78%) is prescribed more frequently than nonsteroidal anti-inflammatory drugs (NSAIDs; 41%) or morphine (3%). Formulations and indications of use varied between faculty physicians and nonfaculty providers. Reasons for prescribing were largely based on anecdotal experience. Based on the survey results, it is clear that more topical agents are needed to manage pain; however, so too is guidance on appropriate prescribing.

Evaluation of the percutaneous absorption of chlorpromazine from PLO gels across porcine ear and human abdominal skin

OBJECTIVE

The overall objective of this work is to determine the percutaneous absorption of chlorpromazine hydrochloride from pluronic lecithin organogels (PLO gels) and verify the suitability of topically applied chlorpromazine hydrochloride PLO gels for use in hospice patients for relieving symptoms such as vomiting and nausea during the end stages of life.

METHODS

PLO gels of chlorpromazine hydrochloride were prepared using isopropyl palmitate (IPP) or ricinoleic acid (RA) as oil phase. In vitro percutaneous absorption of chlorpromazine hydrochloride was assessed through porcine ear and human abdominal skin. Further, the theoretical steady state plasma concentration (Css) of chlorpromazine was calculated from the flux values.

RESULTS

The pH, viscosity, and stability of both PLO gels prepared with IPP and RA were comparable. The thixotropic property of RA PLO gel was found to be better than that of IPP PLO gel. The permeation of chlorpromazine hydrochloride was higher from RA PLO gel than from IPP PLO gel and pure drug solution. Theoretical Css of chlorpromazine from pure drug solution, IPP PLO gel and RA PLO gel were found to be 1.05, 1.20, and 1.50 ng/ml, respectively. PLO gels only marginally increased the flux and theoretical Css of chlorpromazine.

CONCLUSION

From this study, it is clearly evident that PLO gels fail to achieve required systemic levels of chlorpromazine following topical application. Chlorpromazine PLO gel may not be effective in treating nausea and vomiting for hospice patients with swallowing difficulties.

Topical morphine gel for pain management in head and neck cancer patients

Pain is common in head and neck cancer patients. Regardless of the cause, pain management is essential in supportive care. Recent research has suggested that opioid receptors on peripheral nerve terminals may play an important role in pain modulation. A number of publications have reported the use of topical morphine for painful ulcers that occur because of a variety of medical conditions. To the best of our knowledge, there are no reports in the literature regarding the use of morphine gel in head and neck cancer patients. We present two cases treated with morphine gel therapy for cutaneous pain resulting from radiation-induced dermatitis and tumor infiltration. We obtained good pain control in both cases without side effects. In one case, the use of the gel allowed a decrease in systemic opioid medication, and adverse effects of systemic opioid administration were resolved. Our experience suggests that this treatment presents great potential for selected head and neck cancer patients, especially those with prominent pain limited to the body surface.

Systematic review of antimicrobials, mucosal coating agents, anesthetics, and analgesics for the management of oral mucositis in cancer patients

PURPOSE

The aim of this project was to develop clinical practice guidelines on the use of antimicrobials, mucosal coating agents, anesthetics, and analgesics for the prevention and management of oral mucositis (OM) in cancer patients.

METHODS

A systematic review of the available literature was conducted. The body of evidence for the use of each agent, in each setting, was assigned a level of evidence. Based on the evidence level, one of the following three guideline determinations was possible: recommendation, suggestion, or no guideline possible.

RESULTS

A recommendation was developed in favor of patient-controlled analgesia with morphine in hematopoietic stem cell transplant (HSCT) patients. Suggestions were developed in favor of transdermal fentanyl in standard dose chemotherapy and HSCT patients and morphine mouth rinse and doxepin rinse in head and neck radiation therapy (H&N RT) patients. Recommendations were developed against the use of topical antimicrobial agents for the prevention of mucositis. These included recommendations against the use of iseganan for mucositis prevention in HSCT and H&N RT and against the use of antimicrobial lozenges (polymyxin-tobramycin-amphotericin B lozenges/paste and bacitracin-clotrimazole-gentamicin lozenges) for mucositis prevention in H&N RT. Recommendations were developed against the use of the mucosal coating agent sucralfate for the prevention or treatment of chemotherapy-induced or radiation-induced OM. No guidelines were possible for any other agent due to insufficient and/or conflicting evidence.

CONCLUSION

Additional well-designed research is needed on prevention and management approaches for OM.

Novel patch for transdermal administration of morphine

CONTEXT

Transdermal absorption of morphine into the systemic circulation through intact skin has not been reported.

OBJECTIVES

To describe a novel transdermal formulation for a morphine hydrochloride patch consisting of polyethylene sponge foam as the retaining agent and adjusted proportions of morphine hydrochloride and adjunctive drugs.

METHODS

In this study, the transdermal morphine hydrochloride patch was administered to intact skin in five subjects and the plasma concentrations of morphine and its metabolites were examined.

RESULTS

Morphine was absorbed systemically, producing plasma morphine concentrations above the assay detection limit by at least 24 hours after attachment of patches containing a total dose of 180mg of morphine. The levels gradually increased in a time-dependent manner without serious events. The area under the concentration-time curve from 0 to 72 hours (AUC(0-72)) values for morphine, morphine-6-glucuronide, and morphine-3-glucuronide were 60.4±13.4, 133.7±17.4, and 861.5±126.7ng·h/mL, respectively. The mean plasma area under the concentration-time curve from 0 to 72 hours ratio for morphine-6-glucuronide relative to morphine was 2.64.

CONCLUSION

These data provide useful information for developing a transdermal morphine system.

Topical morphine gel in the treatment of painful leg ulcers, a double-blind, placebo-controlled clinical trial: a pilot study

Chronic painful wounds, a major health problem, have a detrimental impact on the quality of life due to associated pain. Some clinical reports have suggested that local administration of morphine could be beneficial. The aim of this study was to evaluate the analgesic effect of topically applied morphine on chronic painful leg ulcers. Twenty-one patients were randomly assigned to receive either morphine or placebo in a randomised, placebo-controlled, crossover pilot study. Each patient was treated four times in total. Pain was measured by the visual analogue score (VAS) before application of gel, directly after and after 2, 6, 12 and 24 hours. Although an overall, clinically relevant, reduction of pain was observed upon treatment with morphine, the difference was not statistically significant. Morphine reduced pain scores more than placebo on treatment occasions 1 and 2. The difference was statistically significant only 2 hours after dressing on the first treatment occasion. Thus, our study did not demonstrate a consistent and globally significant difference in nociception in patients treated with morphine. However, the relatively small number of patients included in our study and other methodological limitations makes it difficult for us to draw general conclusions regarding efficacy of topically applied morphine as an effective treatment for some painful ulcers. Further studies are warranted to evaluate the value of topically applied morphine in the treatment of patients with chronic painful leg ulcers.

Should topical opioid analgesics be regarded as effective and safe when applied to chronic cutaneous lesions?

Objectives

The induction of analgesia for many chronic cutaneous lesions requires treatment with an opioid analgesic. In many patients suffering with these wounds such drugs are either contraindicated or shunned because of their association with death. There are now case reports involving over 100 patients with many different types of chronic superficial wounds, which suggest that the topical application of an opioid in a suitable gel leads to a significant reduction in the level of perceived pain.

Key findings

Some work has been undertaken to elucidate the mechanisms by which such a reduction is achieved. To date there have been no proven deleterious effects of such an analgesic system upon wound healing. Although morphine is not absorbed through the intact epidermis, an open wound provides no such barrier and for large wounds drug absorption can be problematic. However, for most chronic cutaneous lesions, where data has been gathered, the blood levels of the drug applied ranges from undetectable to below that required for a systemic effect.

Summary

If proven, the use of opioids in this way would provide adequate analgesia for a collection of wounds, which are difficult to treat in patients who are often vulnerable. Proof of this concept is now urgently required.

Management of cancer-related pain

Patients and families struggling with cancer fear pain more than any other physical symptom. There are also significant barriers to optimal pain management in the emergency setting, including lack of knowledge, inexperienced clinicians, myths about addiction, and fears of complications after discharge. In this article, we review the assessment and management options for cancer-related pain based on the World Health Organization (WHO) 3-step approach.

Pain management in epidermolysis bullosa

Pain is an unfortunate constant in the lives of most patients with epidermolysis bullosa (EB), especially for those with the more severe types of EB. Patients with EB have a broad spectrum of need for pain treatment, varying with the type of EB, the severity within that type, and the particular physical, emotional, and psychological milieu of each individual. Prevention of situations that precipitate trauma to the skin or exacerbate other pain-inducing complications of this multifaceted disorder is the primary goal of the treating physician. The approach to pain management is different in daily life, during intermittent exacerbations or injuries, or when hospitalizations or operative procedures occur.

Management of cancer-related pain

Patients and families struggling with cancer fear pain more than any other physical symptom. There are also significant barriers to optimal pain management in the emergency setting, including lack of knowledge, inexperienced clinicians, myths about addiction, and fears of complications after discharge. In this article, we review the assessment and management options for cancer-related pain based on the World Health Organization (WHO) 3-step approach.

Effectiveness of topical administration of opioids in palliative care: a systematic review

The discovery of peripheral opioid receptors has become the scientific basis for topical use of opioids in malignant and nonmalignant ulcers and oropharyngeal mucositis. This systematic review aimed to assess the quality of published literature and to examine whether topical opioids are effective in controlling pain in palliative care settings. After a systematic literature review, 19 studies (six randomized controlled trials [RCTs] and 13 case reports) met the inclusion criteria for the review. Eighteen studies favored topical opioids in pain relief, as evidenced by reductions in post-treatment pain scores, but time to onset and duration of analgesia varied widely. Because of the heterogeneity of the studies, meta-analysis was not possible. Despite clear clinical benefits described in small RCTs, there is a deficiency of higher-quality evidence on the role of topical opioids, and more robust primary studies are required to inform practice recommendations. N-of-1 trials should be encouraged for specific clinical circumstances.

Topical dressings to manage pain in venous leg ulceration

The pain experienced by patients with venous leg ulceration can be severe, disabling and have an impact on their quality of life. Pain assessment should be an integral part of leg ulcer assessment, since unless pain is successfully managed, the patient may not be able to comply with compression bandaging or exercise and elevation, all of which are crucial components in the successful management of venous leg ulceration. Neuropathic pain can be difficult to identify for both patient and healthcare professional, if it is unrecognized and untreated the patient's ulceration may persist due to an inability to tolerate dressings or bandaging.

Topical fentanyl in a randomized, double-blind study in patients with corneal damage

OBJECTIVES

Corneal damage causes severe pain. This study investigated whether peripheral opioid receptors are present in the human cornea and assessed the efficacy of topical fentanyl in patients with corneal erosion.

METHODS

Immunohistochemical staining experiments were performed to examine the presence of both mu and delta-receptors on peripheral nerve fibers within human corneal tissue. In a randomized, double-blind clinical trial dexpanthenol (n=20) or dexpanthenol plus 10 microg fentanyl (n=20) were topically applied every 4 hours to the eye of patients with a surgical intervention of corneal damage and subjective pain intensity was determined by a numerical rating scale.

RESULTS

Immunohistochemical staining identified peripheral nerve fibers in human cornea expressing both mu and delta-opioid receptors. In patients with corneal damage the ophthalmic intervention in local anesthesia decreased the subjective pain intensity significantly. At 4-hour intervals after the ophthalmic intervention, moderate pain intensity levels were not altered by the application of dexpanthenol with or without fentanyl. At 24 hours pain intensity dropped significantly, most likely owing to a natural decrease in pain, because the erosion was almost healed.

DISCUSSION

Both mu and delta-receptors are localized on nerve fibers within the cornea, which are accessible for topical opioid treatment. However, our formulation and dose of topical fentanyl in combination with dexpanthenol did not show any benefit in relieving pain from corneal erosion. Future studies are planned to determine the optimal protocol and dose of topical opioid treatment.

Doxepin rinse for management of mucositis pain in patients with cancer: one week follow-up of topical therapy

This study assessed the effectiveness of oral doxepin rinse for mucositis-related pain management in patients following 1 week of repeated dosing. Patients with oral mucositis due to head and neck radiation therapy or hematopoietic stem cell transplant (HSCT) were recruited to participate in a 1-week follow-up study. Subjects who gave informed consent rinsed with doxepin (5 ml) during the initial visit and were then told to use doxepin rinse over the next week as needed, three to six times per day, and return for a follow-up visit. At each visit, mucositis was scored using the Oral Mucositis Assessment Scale and oral pain was assessed using a visual analogue scale before and after rinsing. The use of a systemic analgesic was recorded, and side effects were documented. At the follow-up visit, subjects were also asked to retrospectively report average pain scores they experienced over the past week, 5 and 15 minutes following rinse. Nine subjects were enrolled in the study. Statistically significant reductions in pain scores were reported for 2 hours following doxepin rinse during the initial visit (p < .05). Patients recalled that their pain significantly dropped within 5 minutes of rinsing over the week of repeated dosing (p < .05). At the follow-up visit, subjects reported statistically significant pain reduction 5 minutes after doxepin rinsing (p < .05). These results indicate that doxepin rinsing continues to produce reduced intensity of pain levels over a 1-week span of repeated dosing.

Morphine bioavailability from a topical gel formulation in volunteers

Although available therapies provide relief to many patients with cancer-related pain, swallowing difficulties or intestinal obstruction may preclude oral analgesic delivery in some. Topical morphine might provide an alternate delivery form but morphine bioavailability from a topical gel formulation has not been reported in humans. We conducted a randomized, placebo-controlled, double-blind, crossover study of five volunteers after they provided institutionally-approved, written, informed consent. They were admitted to the Northwestern University General Clinical Research Center twice, being randomly assigned to receive either 1mL of morphine compounded at 10mg/mL in pluronic lecithin organogel (PLO) base applied to the wrist and 1mL of normal saline administered subcutaneously, or 1mL of topical drug-free PLO base and 1mL of subcutaneous morphine, 3mg/mL, the first time and the opposite combination the second. Seventeen blood samples were collected from 5minutes to 10hours after dose administration for morphine concentration determination. Plasma samples were prepared by solid-phase extraction and morphine concentrations measured by a mass spectrometric technique with a linear range of 0.5-500ng/mL. Bioavailability of the topical formulation relative to the subcutaneous dose was to be estimated from doses and the plasma morphine concentration versus time relationships. Because morphine was seldom detected in plasma samples after topical administration and was unquantifiable when it was, the low bioavailability of topical morphine was unquantifiable. These results suggest that topical administration of morphine compounded in a PLO base for transdermal drug delivery is unlikely to provide relief of cancer-related pain.

Topical analgesics

Historically, analgesics were applied by the topical route of administration. With the advent of oral formulations of drugs, topical application became less popular among physicians, although patients still rated this method of drug delivery as efficacious and practical. We now appreciate that peripheral mechanisms of actions of a variety of preparations rationalizes their topical application and gives further opportunity to target peripheral receptors and neural pathways that previously required systemic administration to achieve therapeutic effect. Therefore, a peripheral effect can be generated by using locally applied drug and, consequently, systemic concentrations of that drug may not reach the level at which systemic side effects can occur.

Endogenous opioid peptides, endomorphin-1 and -2 and deltorphin I, stimulate angiogenesis in the CAM assay

The opioid peptides modulate extensive bioactivities, including pain, cardiovascular response, development and so on. The effects of endogenous opioid peptides on angiogenesis were evaluated in the chick embryo chorioallantoic membrane (CAM) assay for the first time in the present study. Endomorphin-1, endomorphin-2 and deltorphin I at the dosage of 1, 10, 100 nmol/embryo could stimulate angiogenesis dose-dependently, respectively. Naloxone, the nonselective opioid receptor antagonist, did not influence angiogenesis alone; but it could antagonize the stimulative effects of the opioid peptides on angiogenesis when it was administrated in combination with the opioid peptides. Taken altogether, the results suggested that endogenous opioid peptides (endomorphin-1 and -2 and deltorphin I) stimulated angiogenesis in the CAM assay, and these effects were modulated with the opioid receptors. These data are important for potential future clinical implementation.

A randomised controlled trial to test the analgesic efficacy of topical morphine on minor superficial and partial thickness burns in accident and emergency departments

OBJECTIVES

To test the analgesic efficacy of topical morphine on superficial burns within the emergency department by comparing pain scores, comfort ratings and analgesia taken by participants.

METHOD

A placebo-controlled three-treatment randomised controlled trial was undertaken. 59 participants were randomly allocated to receive a dressing containing Intrasite gel and morphine sulphate, Intrasite gel and water or the conventional Jelonet dressing. The study design enabled double-blinding between the two Intrasite gel treatments.

RESULTS

49 participants were included in the final analysis as 10 were lost to follow-up. No significant differences were observed between the pain scores or comfort ratings of the three treatments. Participants receiving Jelonet and the placebo reduced their pain scores by the greatest amount overall. However, participants receiving morphine were the only group to reduce pain scores by >20 mm on two consecutive time intervals (2 and 6 h). At 12 h the morphine group reported the highest pain scores. Only 4/15 participants receiving topical morphine administered additional analgesia compared with 12/17 receiving the Jelonet dressing and 6/17 receiving Intrasite and water (p = 0.055). However, when all analgesia was taken into account, the morphine group was administered the greatest amount. Overall, the placebo group reported their dressings to be the most comfortable and took the least amount of analgesia. Minor adverse reactions included itching, burning and a rash. No serious adverse reactions were reported.

CONCLUSIONS

Topical morphine sulphate does not seem to be as effective when used for the pain associated with superficial burns as when used for the pain associated with chronic inflammatory wounds. (The European Clinical Trials Database number for this study is 2005-003285-42.).

Opioids

Opioids are the most effective and widely used drugs in the treatment of severe pain. They act through G protein-coupled receptors. Four families of endogenous ligands (opioid peptides) are known. The standard exogenous opioid analgesic is morphine. Opioid agonists can activate central and peripheral opioid receptors. Three classes of opioid receptors (mu, delta, kappa) have been identified. Multiple pathways ofopioid receptor signaling (e.g., G(i/o) coupling, cAMP inhibition, Ca++ channel inhibition) have been described. The differential regulation of effectors, preclinical pharmacology, clinical applications, and side effects will be reviewed in this chapter.

Topical analgesics

Our knowledge and understanding of the pathophysiology and treatment of pain is increasing; however, we should not lose sight of the simple opportunities that exist for intercepting pain at peripheral targets. Although systemic medication often has peripheral and central modes of action, the appeal for provision of medication close to where these peripheral targets exist should be high. If these sites can be attacked with relatively high concentrations of active drug while keeping systemic levels of that drug below the level at which systemic side effects become apparent, then this should lead to desirable outcomes. Even though the number of true topical agents with an indication for this use is small, a number of other topical agents are available that evidence suggests have the possibility of being effective. Given the increased understanding of pain, the likelihood of further topical agents becoming available is high.

Palliative management of pressure ulcers and malignant wounds in patients with advanced illness

BACKGROUND

Pressure ulcers and malignant wounds are prevalent in populations with advanced illness. In these populations, the goals of care may shift from a primary focus on healing to a focus on wound management, palliation and comfort. Many complications associated with these wounds must be palliated.

OBJECTIVE

This review explores the palliative approach to managing pressure ulcers and malignant wounds in patients with advanced illness.

DESIGN

A comprehensive search of MEDLINE, CINAHL, and Cochrane Databases for articles addressing wound management and palliation was performed. We also reviewed online wound care resources and textbooks related to the field.

CONCLUSIONS

The key to good wound care is prevention if possible, ongoing wound assessment, correct choice of dressing and use of available adjuvant therapies. The ultimate goals of palliative wound care are to control pain, to manage infection, odor, bleeding, and exudate, and to maintain a good quality of life for the patient and caregiver.

Oral doxepin rinse: the analgesic effect and duration of pain reduction in patients with oral mucositis due to cancer therapy

This research expands on our prior study, in which we assessed pain reduction after topical doxepin rinse in patients with oral mucositis resulting from cancer and cancer therapy. We continued to enroll patients with painful oral mucositis attributable solely to cancer therapy and performed further analysis on the duration of pain reduction. Fifty-one patients with oral mucositis were enrolled. Mucositis was scored and oral pain was assessed with a visual analog scale before doxepin oral rinse (5 mg/mL) and at regular intervals up to 4 h after rinsing. Of those who reported pain reduction, 95% did so within 15 min of rinsing with doxepin. In the total sample, the average patient reported a 70% maximum decrease in pain (P < 0.0001). Recurrence of pain was slow and at the conclusion of the study 19 patients (37%) still reported a reduction from baseline pain. With this censored data we used Cox-proportional hazards to determine what variables best explained longer duration of pain reduction. Our final model determined that more severe baseline pain, worse mucosal erythema score, or a larger relative maximum reduction in pain were all associated with a slower rate of pain recurrence after oral rinsing (all P < 0.01).

Opioids heal ischemic wounds in the rat

Opioids are sometimes used to treat pain in ulcerative wounds, and it is speculated that pain interferes with the healing process. Because the direct effect of opioids on this process remains unknown, we examined the effect of topically applied opioids on the healing of open ischemic wounds in rats. Topically applied opioids hastened wound closure, particularly in the first 4 days when no healing was initiated in phosphate buffered saline solution-treated wounds. After 1 week of application, fentanyl, hydromorphone, and morphine resulted in 66%, 55%, and 42% wound closure, respectively, as compared to only 15% in control wounds. Opioid-induced healing was accompanied by a 1.5- to 2.5-fold increase in nuclear density in the granulation tissue and 45-87% increase in angiogenesis as compared to phosphate buffered saline solution-treated wounds. Fentanyl showed significantly improved healing compared to morphine and hydromorphone (p < 0.05, fentanyl vs. others). Fentanyl-induced healing was inhibited by the opioid receptor antagonist naloxone, suggesting that peripheral opioid receptor(s) mediate the healing process. Opioids accelerate healing by up-regulating both endothelial and inducible nitric oxide synthase and the vascular endothelial-derived growth factor receptor Flk1 in the wounds. We envision that opioids can be used topically to accelerate wound healing in diverse clinical conditions ranging from surgical incisions to nonhealing ischemic ulcers in pathophysiological conditions and in hospice patients.

Topische Applikation von Morphingel bei entzündlichen Haut- und Schleimhautläsionen

AIM

The aim of this study was to demonstrate a peripheral local opioid effect using case examples involving inflammatory mucosal and cutaneous lesions.

METHODS

A 0.1% morphine gel, mixed in the hospital pharmacy, was applied several times daily to inflammatory mucosal lesions (oral, anogenital and in one patient to a skin ulcer). The effects and side effects were documented.

RESULT

All patients experienced a significant reduction in pain with the use of topical morphine gel and no side effects were seen.

CONCLUSION

Topical peripheral application of morphine gel is a simple, effective method that can be carried out by patients several times a day with few side effects.

Study to determine the efficacy of topical morphine on painful chronic skin ulcers

OBJECTIVE

To assess the efficacy of the topical application of morphine on painful chronic skin ulcers.

METHOD

A prospective bi-centric controlled double-blind randomised study was conducted involving 24 patients with painful chronic skin ulcers using topically applied morphine versus placebo. Ten milligrams of morphine hydrochloride with Intrasite Gel or Intrasite Gel with placebo were applied daily for five days. All patients were treated with a level II analgesic treatment. A numeric pain scale lower than 4/10 and no need for a 'rescue' treatment (morphine sulphate) indicated that the treatment was successful. Local and systemic tolerance of the treatments was analysed daily.

RESULTS

Twenty-four patients were included in the study, but only 18 started the protocol. Only 2/11 patients were completely relieved in the morphine group compared with 1/7 in the placebo group. Local and general tolerance of morphine was good. The peripheral efficacy of morphine is under discussion.

CONCLUSION

The results suggest that topical morphine cannot be an alternative to morphine administered by other routes (subcutaneously or orally) in painful chronic skin ulcers. Stimulation of peripheral morphine receptors by systemic morphine could explain the difference between these results and those of previous studies.

Analgesic effects of topical methadone: a report of four cases

Topical morphine has been used on open wounds for pain management, but has a variable duration of action not suitable for palliative dressing changes. The objective of this study is to find an opioid and delivery method that would provide long-lasting pain relief between dressing changes. Methadone powder (100 mg) was mixed in Stomahesive powder (10 g) and sprinkled on the open wound once daily at the time of dressing change. Four cases are presented with varying results using the methadone/Stomahesive mixture. Exudative wounds with exposed tissue work best, whereas dry wounds with eschar show less response. Topical methadone powder can be effective for pain relief in open, exudative wounds with little eschar. Further research questions are raised.

Stability of morphine sulphate and diamorphine hydrochloride in intrasite gel

Several studies have reported that opioids applied topically to painful ulcers produce an analgesic effect. It is unknown whether these opioids (usually mixed with hydrogels) are stable and, if so, for how long. We investigated the stability of morphine sulphate and diamorphine hydrochloride, each mixed with intrasite gel at a concentration of 1.25 mg/mL. Samples were prepared in the laboratory and then stored in plastic containers in the dark, at room temperature, in conditions of normal day/night at room temperature, and at 4 degrees C. Aliquots were collected from each container over a 28-day period and analysed using HPLC. No known degradation products were measured in the morphine-intrasite gel mixture stored for up to 28 days, irrespective of the temperature and whether or not samples were exposed to light, suggesting that morphine remains stable. Diamorphine, breaks down to morphine and no other degradation products are measurable.

Analgesia for patients with advanced disease: I

This series of two articles explores the challenge of managing pain in patients with advanced malignant and non-malignant disease. Pain is a common symptom in advanced disease. Despite guidance from organisations such as the World Health Organisation, cancer pain is often inadequately managed. Managing pain in non-malignant conditions, such as end stage cardiac failure, presents an even greater challenge to healthcare professionals. This first article discusses epidemiology, definitions, pathophysiology, assessment, non-pharmacological approaches, the analgesic "ladder", and opioids. The second article will examine the use of non-opioids, anaesthetic techniques, and analgesia in dying patients as well as discussing future directions.