Transdermal fentanyl. A review of its pharmacological properties and therapeutic efficacy in pain control

Parenteral analgesics for pain relief in acute pancreatitis: a systematic review

AIM

To assess the efficiency and safety of parenteral analgesics for pain relief in acute pancreatitis.

MATERIALS AND METHODS

We carried out an electronic search of PubMed, Cochrane Library, EMBASE, WEIPU, CNKI and CBM and a manual search for eligible studies. The methodological quality of included trials and quality of evidence were examined by the Cochrane Collaboration's tool for assessing risk of bias and GRADE, respectively. The data were mainly analyzed descriptively and some were pooled by Review manager 5.

RESULTS

Eight randomized controlled trials with a total of 356 patients were finally included in this systematic review. Compared with procaine, pentazocine led to lower pain severity: day 1, Mean Difference (MD), 95%CI: 40.0 [35.3, 44.7]; day 2, MD, 95%CI: 24.00 [20.88, 27.12]; day 3, MD, 95%CI: 5.00 [2.17, 7.83], and it decreased the requirement for additional analgesics, Relative Risk, 95%CI: 2.23 [1.63, 3.05]. The combination of fentanyl, atropine, droperidol and lidocaine rendered lower pain score: day 1, MD, 95%CI: -5.46 [-6.95, -3.97]; day 2, MD, 95%CI: -5.78 [-7.39, -4.17]. Patients treated with metamizole tended to had lower pain than those treated with morphine, MD, 95%CI: -2.60 [-2.95, -2.25]. Nausea, emesis and vomiting were the common adverse events reported and there was almost no significant difference between different agents on safety.

CONCLUSIONS

The systemic review showed that the randomized controlled trials comparing different analgesics were of low quality and did not favor clearly any particular analgesic for pain relief in acute pancreatitis.

Multicenter clinical study for evaluation of efficacy and safety of transdermal fentanyl matrix patch in treatment of moderate to severe cancer pain in 474 chinese cancer patients

OBJECTIVE

Although a new matrix formulation fentanyl has been used throughout the world for cancer pain management, few data about its efficacy and clinical outcomes associated with its use in Chinese patients have been obtained. This study aimed to assess the efficacy and safety of the new system in Chinese patients with moderate to severe cancer pain.

METHODS

A total of 474 patients with moderate to severe cancer pain were enrolled in this study and were treated with the new transdermal fentanyl matrix patch (TDF) up to 2 weeks. All the patients were asked to record pain intensity, side effects, quality of life (QOL), adherence and global satisfaction. The initial dose of fentanyl was 25 μg/h titrated with opioid or according to National Comprehensive Cancer Network (NCCN) guidelines. Transdermal fentanyl was changed every three days.

RESULTS

After 2 weeks. The mean pain intensity of the 459 evaluated patients decreased significantly from 5.63±1.26 to 2.03±1.46 (P<0.0001). The total remission rate was 91.29%, of which moderate remission rate 53.16%, obvious remission rate 25.49% and complete remission rate 12.64%. The rate of adverse events was 33.75%, 18.78% of which were moderate and 3.80% were severe. The most frequent adverse events were constipation and nausea. No fatal events were observed. The quality of life was remarkably improved after the treatment (P<0.0001).

CONCLUSION

The new TDF is effective and safe in treating patients with moderate to severe cancer pain, and can significantly improve the quality of life.

Opioid-induced bowel dysfunction: pathophysiology and management

Opioids are the most commonly prescribed medications to treat severe pain in the Western world. It has been estimated that up to 90% of American patients presenting to specialized pain centres are treated with opioids. Along with their analgesic properties, opioids have the potential to produce substantial side effects, such as nausea, cognitive impairment, addiction and urinary retention. In the gut, opioids exert their action on the enteric nervous system, where they bind to the myenteric and submucosal plexuses, causing dysmotility, decreased fluid secretion and sphincter dysfunction, which all leads to opioid-induced bowel dysfunction (OIBD). In the clinic, this is reported as nausea, vomiting, gastro-oesophageal reflux-related symptoms, constipation, etc. One of the most severe symptoms is constipation, which can be assessed using different scales for subjective assessment. Objective methods such as radiography and colonic transit time can also be used, together with manometry and evaluation of anorectal function to explore the pathophysiology. Dose-limiting adverse symptoms of OIBD can lead to insufficient pain treatment. Even though several treatment strategies are available, the side effects are still a major challenge. Traditional laxatives are normally prescribed but they are often insufficient to alleviate symptoms, especially those from the upper gastrointestinal tract. Newer prokinetics, such as prucalopride and lubiprostone, may be more effective in alleviating OIBD. Another treatment approach is co-administration of opioid antagonists, which either cannot cross the blood-brain barrier or selectively target opioid receptors in the gastrointestinal tract. However, although these new agents have proved to be more efficacious than placebo, clinical trials still need to prove their superiority to standard co-prescribed laxative regimes.

MicroRNAs in opioid pharmacology

MicroRNAs (miRNA), a class of ~22-nucleotide RNA molecules, are important gene regulators that bind to the target sites of mRNAs to inhibit the gene expressions either through translational inhibition or mRNA destabilization. There are growing evidences that miRNAs have played several regulatory roles in opioid pharmacology. Like other research fields such as cancer biology, the area where numerous miRNAs are found to be involved in gene regulation, we assume that in opioid studies including research fields of drug additions and opioid receptor regulation, there may be more miRNAs waiting to be discovered. This review will summarize our current knowledge of miRNA functions on opioids biology and briefly describe future research directions of miRNAs related to opioids.

MicroRNA 339 down-regulates μ-opioid receptor at the post-transcriptional level in response to opioid treatment

μ-Opioid receptor (MOR) level is directly related to the function of opioid drugs, such as morphine and fentanyl. Although agonist treatment generally does not affect transcription of mor, previous studies suggest that morphine can affect the translation efficiency of MOR transcript via microRNAs (miRNAs). On the basis of miRNA microarray analyses of the hippocampal total RNA isolated from mice chronically treated with μ-opioid agonists, we found a miRNA (miR-339-3p) that was consistently and specifically increased by morphine (2-fold) and by fentanyl (3.8-fold). miR-339-3p bound to the MOR 3'-UTR and specifically suppressed reporter activity. Suppression was blunted by adding miR-339-3p inhibitor or mutating the miR-339-3p target site. In cells endogenously expressing MOR, miR-339-3p inhibited the production of MOR protein by destabilizing MOR mRNA. Up-regulation of miR-339-3p by fentanyl (EC(50)=0.75 nM) resulted from an increase in primary miRNA transcript. Mapping of the miR-339-3p primary RNA and its promoter revealed that the primary miR-339-3p was embedded in a noncoding 3'-UTR region of an unknown host gene and was coregulated by the host promoter. The identified promoter was activated by opioid agonist treatment (10 nM fentanyl or 10 μM morphine), a specific effect blocked by the opioid antagonist naloxone (10 μM). Taken together, these results suggest that miR-339-3p may serve as a negative feedback modulator of MOR signals by regulating intracellular MOR biosynthesis.

Fatal overdose after ingestion of a transdermal fentanyl patch in two non-human primates

CASE HISTORY AND PRESENTATION: Two non-human primates (Macaca fascicularis), weight 3.5 kg, enrolled in an experimental protocol received a 25 μg hour(-1) transdermal fentanyl patch for postoperative analgesia. The following day both animals were clinically normal, but after a new induction of anaesthesia with ketamine, they developed severe and prolonged respiratory distress, profound coma and myosis. MANAGEMENT AND FOLLOW-UP: Attempted reversal with naloxone was ineffective. After several hours of ventilation, both primates eventually died, 7 and 15 hours after ketamine injection, respectively. In both cases, the patch was discovered in the animal's cheek pouch. Subsequent fentanyl serum concentration measurements (8.29 and 14.80 μg L(-1) ) confirmed fentanyl overdose.

CONCLUSIONS

This report of two fatal intoxications in non-human primates secondary to ingestion of a transdermal fentanyl patch demonstrates that this method of analgesia is inappropriate for non-human primates, because of their tendency to chew almost anything they can reach.

Transdermal fentanyl for chronic low back pain

PURPOSE

Chronic low back pain is a common clinical problem. As medication, non-steroidal anti-inflammatory drugs are generally used; however, they are sometimes non-effective. Recently, opioids have been used for the treatment of chronic low back pain, and since 2010, transdermal fentanyl has been used to treat chronic non-cancer pain in Japan. The purpose of the current study was to examine the efficacy of transdermal fentanyl in the treatment of chronic low back pain.

MATERIALS AND METHODS

This study included patients (n=62) that suffered from chronic low back pain and were non-responsive to non-steroidal anti-inflammatory drugs. Their conditions consisted of non-specific low back pain, multiple back operations, and specific low back pain awaiting surgery. Patients were given transdermal fentanyl for chronic low back pain. Scores of the visual analogue scale and the Oswestry Disability Index, as well as adverse events were evaluated before and after therapy.

RESULTS

Overall, visual analogue scale scores and Oswestry Disability Index scores improved significantly after treatment. Transdermal fentanyl (12.5 to 50 μg/h) was effective in reducing low back pain in 45 of 62 patients; however, it was not effective in 17 patients. Patients who experienced the most improvement were those with specific low back pain awaiting surgery. Adverse events were seen in 40% of patients (constipation, 29%; nausea, 24%; itching, 24%).

CONCLUSION

Transdermal fentanyl significantly improved visual analog scale scores and Oswestry Disability Index scores in 73% of patients, especially those with specific low back pain awaiting surgery; however, it did not decrease pain in 27% of patients, including patients with non-specific low back pain or multiple back operations.

Effect of transdermal opioids in experimentally induced superficial, deep and hyperalgesic pain

BACKGROUND AND PURPOSE

Chronic pain and hyperalgesia can be difficult to treat with classical opioids acting predominately at the µ-opioid receptor. Buprenorphine and its active metabolite are believed to act through µ-, κ- and δ-receptors and may therefore possess different analgesic and anti-hyperalgesic effects compared with pure µ-receptor agonists, for example, fentanyl. Here, we have compared the analgesic and anti-hyperalgesic effects of buprenorphine and fentanyl.

EXPERIMENTAL APPROACH

Twenty-two healthy volunteers were randomized to treatment with transdermal buprenorphine (20 µg·h(-1), 144 h), fentanyl (25 µg·h(-1), 72 h) or placebo patches in a double-blind, cross-over experimental pain study. The experimental pain tests (phasic pain, sensitization) involved pressure at the tibial bone, cutaneous electrical and thermal stimulation, intramuscular nerve growth factor, UVB light burn injury model and intradermal capsaicin-induced hyperalgesia. Pain testing was carried out at baseline, 24, 48, 72 and 144 h after application of the drugs.

KEY RESULTS

Compared with placebo, buprenorphine, but not fentanyl, significantly attenuated pressure at the tibial bone as well as pressure pain in the primary hyperalgesic area induced by UVB light The two drugs were equipotent and better than placebo against cutaneous thermal pain stimulation), but failed to show significant analgesic effect to cutaneous electrical stimulation, nerve growth factor-induced muscle soreness and to capsaicin-induced hyperalgesia.

CONCLUSIONS AND IMPLICATIONS

Buprenorphine, but not fentanyl, showed analgesic effects against experimentally induced, bone-associated pain and primary hyperalgesia compared with placebo. These tissue- and modality-differentiated properties may reflect the variable effects of opioid drugs observed in individual patients.

Pharmacist Documentation of Fentanyl Patch Orders in an Academic Medical Center

Purpose

The fentanyl transdermal patch label carries a boxed warning indicating that it should only be used in opioid-tolerant patients. Both prescribers and pharmacists must adhere to these recommendations to ensure safe use of the patches. Our goal was to determine the fentanyl patch documentation rate at our institution and evaluate the quality of documentation, and to make recommendations for improvement if appropriate to ensure patient safety.

Methods

We conducted a retrospective data analysis to determine pharmacist adherence rate to medical center documentation practices for fentanyl patch orders at UC San Diego Medical Center between July 2009 and July 2010.

Results

A total of 296 adult fentanyl patch orders were prescribed during the study period. Sixty-four of these orders were new initiations and 232 orders were continued from outpatient regimens. Overall, pharmacist documentation rate, without regard to completeness of notation, was 97.0%, with no difference between new and continuing orders. Evaluation of the quality of documentation showed that the most important factor lacking in the majority of documentations was duration of previous opioid therapy.

Conclusion

Examination of fentanyl patch documentation data suggests that the existing pharmacy notation system can be improved. We believe that a revised documentation template that includes source of information, chronic pain indication, opioid regimen, duration, daily oral morphine equivalent, pain assessment, and final patch plan will help to ensure the safety of prescribed patches and completeness of documentation. These findings can be used to develop policies and procedures to achieve complete adherence to transdermal fentanyl's boxed warning at any institution.

Three-cycle fentanyl patch system contributes to stable control of plasma fentanyl concentration in gynecologic cancer pain patients

OBJECTIVE

Pain affects many cancer patients in advancing stages, lowering the level of their quality of life. Morphine has long been the "gold standard" for the treatment of cancer pain; however, its side effects, particularly sedation and cognitive impairment at high doses, have encouraged the use of "opioid rotation". The transdermal fentanyl patch has advantages over oral morphine, with reduced side effects and increased convenience in practical usage. The side effects were reduced in patients who changed to the fentanyl patch, but rescue analgesia was often needed because of the decrease of fentanyl release from the patch, especially on patch replacement day. To maintain a stable fentanyl plasma level before patch replacement, we have established a three-cycle fentanyl patch system and reported that it provided appropriate pain control. The objective of this study was to investigate the individual variability of plasma fentanyl concentration in a three-cycle fentanyl patch system.

CASE REPORT

The gynecologic cancer patients were treated using the three-cycle fentanyl patch system. Blood samples were taken from the patients and plasma fentanyl concentration was analyzed. A stable plasma fentanyl level was observed, and good pain control was achieved in each patient using the three-cycle fentanyl patch system. A stable plasma fentanyl level was maintained the day before the conventional patch replacement day.

DISCUSSION

The three-cycle fentanyl patch system provided a stable plasma fentanyl concentration and excellent pain relief and should be considered for pain control in cancer patients.

The impact of fentanyl matrix on pain and function in spinal disorder-related chronic pain: an open label trial in Korea

Study Design

This is a multicenter, open-label prospective, non interventional study.

Purpose

We wanted to evaluate the impact of fentanyl matrix on the pain and function of patients with spinal disorder-related chronic, non-malignant pain.

Overview of Literature

Patients with severe non-malignant chronic low back pain may require opioid analgesics for effective pain management.

Methods

A total of 1,576 patients with severe pain (numeric rating scale = 7) were evaluated for their pain intensity at the initial visit and at weeks 4 and 8 (Visits 1, 2, and 3, respectively). Disturbances in sleep, daily living and social activities, the Oswestry Disability Index (ODI), the researchers' and patients' global assessment and the patients' treatment preference were also assessed.

Results

The pain intensity score significantly decreased from 8.1 at Visit 1 to 5.4 and 4.4 at Visits 2 and 3, respectively. Sleep disturbance also significantly decreased and the extent of disturbance of daily and social activities was also significantly improved. The ODI significantly decreased from 61.9% to 45.8% and 38.2% at Visits 1, 2, and 3, respectively. Adverse events were reported by 197 (12.5%) patients and severe adverse events were reported by 12 (0.76%) patients. Overall, 76.3% of the patients and 78.4% of the investigators rated the test drug as effective.

Conclusions

The fentanyl matrix is believed to be effective for the treatment of pain, sleep disturbance and the impact upon daily and social activities, yet physicians should pay attention to the risks of abuse and the adverse events.

Fentanyl sublingual: in breakthrough pain in opioid-tolerant adults with cancer

Fentanyl is a potent opioid with a short duration of action. Fentanyl sublingual has been formulated as a rapidly disintegrating tablet that is quickly absorbed, producing a fast onset of analgesia. In two randomized, double-blind clinical trials, fentanyl sublingual as single fixed or titrated doses reduced pain intensity during breakthrough pain episodes to a significantly greater extent than placebo in opioid-tolerant cancer patients. In a fixed-dose phase II trial and a titrated-dose phase III trial, fentanyl sublingual (as a single 400 μg dose and as titrated doses) reduced mean pain intensity difference (PID) to a significantly greater extent than placebo over the entire treatment period (up to 60 minutes), reaching statistical significance 15 minutes post-dose. In the titrated-dose study, the mean sum of PID (area under the PID vs time curve) at 30 minutes post-dose was significantly greater with fentanyl sublingual than placebo, with significant improvements in PID seen at 10 minutes maintained at 60 minutes post-dose. In the phase III study, patients receiving fentanyl sublingual were more satisfied with their treatment than patients receiving placebo (measured using the Patient Global Evaluation of Medication score), and almost half of all fentanyl sublingual recipients were satisfied or very satisfied with their treatment. Fentanyl sublingual was generally well tolerated in the two trials and most adverse events were mild to moderate in intensity.

Pain Management and Symptom-Oriented Drug Therapy in Palliative Care

SUMMARY: Patients with advanced life-limiting disease often suffer from symptoms that considerably impair their quality of life and that of their families. Palliative care aims to alleviate these symptoms by a multidimensional approach. Pharmacotherapy is an essential component. The objective of this review is to give an overview of symptom-oriented drug therapy for the most important symptoms in palliative care. Leading symptoms that affect quality of life include pain, dyspnea, nausea and emesis, weakness and disorientation. Careful examination and history taking help to understand the individual mechanisms underlying these symptoms. Specific pharmacotherapy provides an efficient way to achieve symptom control in the context of palliative care.

Oral-parenteral conversion factor for morphine in palliative cancer care: a prospective randomized crossover pilot study

Objective. This pilot study clinically tests whether a conversion factor of 2 to 1 is appropriate when changing from oral to parenteral morphine administration in the treatment of cancer-related nociceptive pain and calculates the size of an adequately powered future study. Methods. Eleven outpatients with incurable cancer and well-controlled nociceptive pain were randomly assigned to either intravenous or subcutaneous morphine using half the previous oral 24-hour dose. Each group crossed over after the first three-day period. Serum concentrations of morphine and its metabolites were monitored as well as intensity of pain. Results. Oral to subcutaneous and oral to intravenous quotas of morphine concentrations were approximately 0.9. Subcutaneous to intravenous morphine quotas were 1. Conclusions. The conversion factor of 2 to 1 seems to be a reasonable average but with an obvious need for individual adjustments. Concurrent medications and substantially higher doses of morphine could potentially affect the appropriate conversion factor. An adequately powered study to validate these findings would need at least 121 patients.

Fentanyl Transdermal Therapy System (TTS-Patch) for Post-Traumatic Blunt Chest Injury

Proper post-extubation pain control in traumatic blunt chest injury represents a challenge to provide adequate analgesia for proper lung inflation and to prevent re-intubation. In this case, the average opioid (Remifentanil) infusion drip in a traumatic blunt chest injury patient in the 48 hours prior to extubation was calculated and converted to the equivalent analgesic one of the Fentanyl Transdermal Therapeutic System (Fentanyl TTS Patch). The analgesic gap before the onset of action for the applied fentanyl patch was covered by frequent injections of tramadol. Evaluation of the Fentanyl TTS effect through the post-extubation period was carried out by measuring the analgesic effect on a visual analogue scale, the alertness status by simple sedation score, while the respiratory performance was followed by the negative inspiratory force. The outcome in this case showed that Fentanyl Patch is a reliable, favorable, safe and non-invasive method that produces a good analgesic effect and positive impaction on the post-extubation course of respiratory performance with a satisfactory outcome and no side effects.

Formulations of fentanyl for the management of pain

Fentanyl is an opioid initially developed for parenteral administration. While oral administration is not an option due to a high first-pass metabolism, its high potency and lipophilicity have made a number of new routes of administration feasible. The transdermal therapeutic system offers an excellent option for long-term treatment of cancer and chronic pain, achieving stable plasma concentrations over the treatment period. The recent change from reservoir to matrix systems has made these systems more convenient to wear and safer to use, while being bioequivalent. In contrast, the patient-controlled iontophoretic transdermal system has been developed to enable on-demand delivery of transdermal bolus doses of fentanyl to treat postoperative pain. It offers a needle-free system to provide patient-controlled analgesia otherwise offered by intravenous pumps. However, due to technical difficulties the system is currently not clinically available. Oral transmucosal fentanyl utilizes the rapid uptake through the buccal mucosa to achieve high plasma concentrations rapidly and is indicated to treat breakthrough pain in patients who are not opioid-naive. The recently introduced fentanyl buccal tablets offer slightly better pharmacokinetics for the same indication. The intranasal route is another option to achieve rapid uptake of fentanyl, and is currently being investigated to provide acute and breakthrough pain relief. Transpulmonary administration of fentanyl remains experimental and this route of administration is not yet in clinical use. Overall, the specific pharmacological and physicochemical properties of fentanyl have made this compound highly suitable for novel routes of administration in a range of clinical indications.

Transdermal fentanyl: pharmacology and toxicology

OBJECTIVE

To evaluate the underlying pharmacology, safety, and misuse/abuse of transdermal fentanyl, one of the cornerstone pharmacotherapies for patients with chronic pain.

METHODS

Literature was identified through searches of Medline (PubMed) and several textbooks in the areas of pharmacology, toxicology, and pain management. A bibliographical review of articles identified by these searches was also performed. Search terms included combinations of the following: fentanyl, transdermal, patch, pharmacology, kinetics, toxicity, and poisoning. All pertinent clinical trials, retrospective studies, and case reports relevant to fentanyl pharmacology and transdermal fentanyl administered by any route and published in English were identified. Each was reviewed for data regarding the clinical pharmacology, abuse, misuse, and safety of transdermal fentanyl. Data from these studies and information from review articles and pharmaceutical prescribing information were included in this review.

RESULTS

Fentanyl is a high-potency opioid that has many uses in the treatment of both acute and chronic pain. Intentional or unintentional misuse, as well as abuse, may lead to significant clinical consequences, including death. Both the US Food and Drug Administration (FDA) and Health Canada have warned of potential pitfalls associated with transdermal fentanyl, although these have not been completely effective in preventing life-threatening adverse events and fatalities related to its inappropriate use.

CONCLUSIONS

Clinically consequential adverse effects may occur unexpectedly with normal use of transdermal fentanyl, or if misused or abused. Misuse and therapeutic error may be largely preventable through better education at all levels for both the prescriber and patient. The prevention of intentional misuse or abuse may require regulatory intervention.

The use of transdermal fentanyl in cancer pain--a compliance study of outpatients in Taiwan

The aim of this study is to investigate cancer patients' response and side effects associated with transdermal therapeutic fentanyl (TTS-F), whose pain was hardly controlled by nonweak/weak opioids in Taiwan. From 2005 to 2006, 822 outpatients received TTS-F to collect pain assessment forms and diaries for 4 weeks. Most (78.7%) patients were initially prescribed 25 microg/h TTS-F. Doses were adjusted weekly at clinicians' discretion, according to pain assessment and side effects. Patients receiving 50 microg/h, 75 microg/h, and > 75 microg/h TTS-F had increased from 17.5% to 32.1%, 1.8% to 3.4%, and 1.9% to 2.2%, respectively, by week 2; further small increases were found in weeks 3 and 4. Pain palliation improved from 60.6% during week 1 to 78.6% at week 4. The common adverse effects were nausea/vomiting. Patient's compliance was >90%. This study found that the TTS-F is effective and well tolerated.

A One Year Health Economic Model Comparing Transdermal Fentanyl with Sustained-Release Morphine in the Treatment of Chronic Noncancer Pain

A Markov model was constructed to simulate the resource use and health outcomes of one year of treatment comparing the fentanyl transdermal therapeutic system (fentanyl-TTS) with oral sustained-release (SR) morphine in outpatients with noncancer pain in Denmark. Effectiveness was assessed in terms of days of good pain control and days on initial treatment. Costs included those of baseline pain management, including breakthrough pain; co-medication costs; and control of adverse events. Fentanyl-TTS was more effective than SR-morphine in achieving good pain control (99 vs. 64 days, respectively) and the incremental cost-effectiveness of fentanyl-TTS was US dollars 10.26 per extra day of good pain control. Patients treated with fentanyl-TTS remained considerably longer on initial treatment compared with those treated with SR-morphine (166 days vs. 117 days, respectively). The results of this study suggest that fentanyl-TTS is a competitive therapeutic and economic choice for the treatment of chronic noncancer pain.

Pain syndromes in sickle cell disease: an update

OBJECTIVE

Pain has a critical role in the management of sickle cell disease (SCD). Patients may suffer from several pain syndromes, which may be or not may be associated with other clinical complications, such as anemia, organ failures, and infections.

DESIGN

Data for review were identified by using PubMed to search MEDLINE, limiting the search to abstract/articles in English, Italian, French, and Dutch. The key words pain, sickle cell disease, anemia, hemoglobin, hemoglobinopathy, analgesics, opioids, morphine, acetaminophen, paracetamol, nonsteroidal anti-inflammatory drugs, hematology, and quality of life were variously combined in the title, abstract, and key word search list. The abstract database of most hematological congresses and the bibliographies of most relevant articles were also considered.

RESULTS

There are two major types of SCD pain: acute and chronic. Sometimes, mixed and neuropathic pain can be also observed. Acute pain is mostly related to vaso-occlusion. Chronic pain may be due to some SCD complications, such as leg ulcers and avascular necrosis.

CONCLUSIONS

Pain management in the SCD setting needs multidisciplinary approaches, given the several syndromes and the pathogenic mechanisms that are likely involved. Pain management is not standardized and often difficult, so that many patients with SCD are still poorly treated. Further efforts to develop care plans and treatment protocols as well as management guidelines are required.

Multiscale modeling framework of transdermal drug delivery

This study addresses the modeling of transdermal diffusion of drugs to better understand the permeation of molecules through the skin, especially the stratum corneum, which forms the main permeation barrier to percutaneous permeation. In order to ensure reproducibility and predictability of drug permeation through the skin and into the body, a quantitative understanding of the permeation barrier properties of the stratum corneum (SC) is crucial. We propose a multiscale framework of modeling the multicomponent transdermal diffusion of molecules. The problem is divided into subproblems of increasing length scale: microscopic, mesoscopic, and macroscopic. First, the microscopic diffusion coefficient in the lipid bilayers of the SC is found through molecular dynamics (MD) simulations. Then, a homogenization procedure is performed over a model unit cell of the heterogeneous SC, resulting in effective diffusion parameters. These effective parameters are the macroscopic diffusion coefficients for the homogeneous medium that is "equivalent" to the heterogeneous SC, and thus can be used in finite element simulations of the macroscopic diffusion process. The resulting drug flux through the skin shows very reasonable agreement to experimental data.

Efficacy and safety of transdermal fentanyl for treatment of oral mucositis pain caused by chemotherapy

BACKGROUND/OBJECTIVE

We investigated the efficacy and safety of transdermal fentanyl for severe mucositis pain caused by chemotherapy.

METHODS

Thirty-two patients who had moderate to severe pain using the Numeric Rating Scale (NRS) were enrolled in this study. The analgesic effect, quality of life and side effects were evaluated after the administration of transdermal fentanyl.

RESULTS

The median NRS score was reduced from 6 (range 4 - 9) before treatment to 4 (range 0 - 9), 2.5 (range 0 - 8), 2 (range 0 - 8), 2 (range 0 - 6) and 0 (range 0 - 5) on days 3, 5, 7, 10 and 15, respectively, after treatment (p < 0.001). The patients' quality of life also improved significantly (p < 0.01). The side effects of treatment were mild, and disappeared within several days.

CONCLUSIONS

Transdermal fentanyl is an effective, convenient and well-tolerated treatment for severe mucositis pain caused by chemotherapy that can improve patients' quality of life.

Fentanyl transdermal matrix patch (Durotep MT patch; Durogesic DTrans; Durogesic SMAT): in adults with cancer-related pain

The fentanyl transdermal matrix patch is approved in Japan for the management of moderate to severe cancer-related pain in adults. Bioequivalence, in terms of exposure and the maximum and minimum serum concentrations, has been established between the fentanyl transdermal matrix patch 16.8 mg (100microg/h) and the fentanyl transdermal reservoir patch 10 mg (100microg/h) after single and multiple applications. The fentanyl transdermal matrix patch 2.1-8.4 mg (12.5-50microg/h) effectively managed chronic cancer-related pain in adults in a noncomparative, multicentre, phase II study; 89.4% of recipients rated their global assessment of pain as 'very satisfied', 'satisfied' or 'neither satisfied nor dissatisfied'. Adults with cancer- or non-cancer-related chronic pain were switched from fentanyl transdermal reservoir patch to fentanyl transdermal matrix patch therapy without compromising efficacy; no differences in pain intensity or sleep interference scores were seen between the two formulations in an nonblind, multicentre, switching pilot study. Given the nature of the therapy, the tolerability profile of the fentanyl transdermal matrix patch was generally acceptable. Topical adverse events included erythema, application-site irritation and pruritus. In general, patients and physicians preferred the fentanyl transdermal matrix patch over the fentanyl transdermal reservoir patch in the pilot study.

Transdermal matrix fentanyl membrane patch (matrifen): in severe cancer-related chronic pain

The matrix fentanyl membrane patch is a new transdermal patch designed with a reduced drug load compared with established reservoir and matrix fentanyl patches. The drug is contained within a silicone matrix with a rate-controlling membrane designed to maintain constant serum fentanyl concentrations over the 72-hour application period. The matrix fentanyl membrane patch was equivalent to the reservoir fentanyl patch in terms of transdermal delivery of fentanyl, as demonstrated after both single (100 microg/h) and multiple (50 microg/h) applications by the peak serum fentanyl concentration and the area under the serum concentration-time curve over 72 hours. In a randomized, nonblind, multicentre trial, the transdermal matrix fentanyl membrane patch was noninferior to standard opioid therapy (transdermal reservoir or matrix fentanyl patch or an oral opioid) in terms of analgesic efficacy over 30 days in patients with cancer-related chronic pain requiring long-term opioid use. The transdermal matrix fentanyl membrane patch was as well tolerated as standard opioid therapy; patient-rated tolerability scores for constipation, nausea, daytime drowsiness and sleep disturbance were similar between treatments.

Opioid-induced immunosuppression

PURPOSE OF REVIEW

This review provides an overview of the immunological effects of commonly used analgesic opioid drugs with particular emphasis on human studies, with the final aim to highlight their potential clinical relevance.

RECENT FINDINGS

The immunomodulatory effects of morphine have been characterized in animal and human studies. Morphine decreases the effectiveness of several functions of both natural and acquired immunity, interfering with important intracellular pathways involved in immune regulation. Mainly from animal studies, however, it has emerged that not all opioids induce the same immunosuppressive effects and evaluating each opioid's profile is important for appropriate analgesic selection. The potent opioid fentanyl also exerts a relevant immunosuppression, while the partial agonist buprenorphine appears to have a more favourable immune profile. The impact of the opioid-mediated immune effects could be particularly dangerous in selective vulnerable populations, such as the elderly or immunocompromised patients.

SUMMARY

The impact of opioid drug treatment on immunity may be a new safety concern for the physician. Although many advances have been made in understanding the effects of opioid drugs on immune responses, their relevance is not completely clear. The scientific community must be aware that it is about time to perform well designed clinical studies in order to assess the importance of opioid-induced immune suppression.

Efficacy, safety and pharmacokinetic study of a novel fentanyl-containing matrix transdermal patch system in Japanese patients with cancer pain

BACKGROUND AND OBJECTIVES

A novel transdermal matrix patch delivery system for fentanyl has been developed to deliver improved management of cancer pain compared with that obtained using current fentanyl reservoir patches. This study was carried out to assess the efficacy, safety and pharmacokinetic profiles of a 12.5 microg/h transdermal matrix fentanyl patch administered with the objective of replacing morphine, oral oxycodone or fentanyl injection formulations. The study also evaluated how the pharmacokinetic profiles of higher dose fentanyl patches (25, 37.5 and 50 microg/h) changed following dose adjustments to optimize management of cancer pain.

METHODS

This open-label, multicentre study involved 87 patients of both sexes (> or =20 years) with a confirmed diagnosis of cancer. Patients were receiving any one of the following at the time of enrollment for the management of their cancer pain: (a) morphine <45 mg/day orally, <30 mg/day as suppositories, or <15 mg/day by injection; (b) oral oxycodone <30 mg/day; or (c) fentanyl injectable preparations <0.3 mg/day. The patients were administered a 3-day course of fentanyl transdermal matrix patch application three times. The initial dose was 12.5 microg/h, which could be increased when a new patch was applied if the physician deemed this to be appropriate based on pain intensity ratings and use of rescue medications. Efficacy outcomes included patients' global assessment scores (primary efficacy endpoint) measured on a five-step scale and dichotomous scores for physicians' global assessment. The occurrence of adverse events and changes in laboratory tests were evaluated as safety variables. Serum fentanyl levels were measured immediately after removal of the old patch on days 4, 7 and 10 to obtain data on trough serum concentrations.

RESULTS

The percentage of patients in category 3 or higher (very satisfied, satisfied, or neither satisfied nor dissatisfied) for the patient's global assessment score was 89.4% (76/85), indicating high patient satisfaction and attainment of sufficient pain control after patients switched from their previously used opioid analgesics. Similar findings were obtained on physicians' global assessment scores. A total of 316 adverse events occurred in 78 (90.7%) of 86 patients who were administered at least one patch. These included nausea (31 [36.0%]), somnolence (26 [30.2%]), vomiting (22 [25.6%]), diarrhoea (17 [19.8%]), constipation (14 [16.3%]), pyrexia (11 [12.8%]) and insomnia (9 [10.5%]). The mean (+/- SD) serum fentanyl concentration determined on day 4 was 169.9 +/- 103.4 pg/mL (n = 83). Serum fentanyl measurement results indicated that the same fentanyl patch dose resulted in similar serum fentanyl levels, while increased doses produced higher serum fentanyl concentrations.

CONCLUSION

The fentanyl matrix transdermal patch formulation employed in this study demonstrated sufficient cancer pain control for patients switching from morphine or oral oxycodone preparations. The patch tested was well tolerated and its use did not result in any increased incidence of adverse drug reactions over those commonly found with opioid analgesics.

A randomized, open, parallel group, multicenter trial to investigate analgesic efficacy and safety of a new transdermal fentanyl patch compared to standard opioid treatment in cancer pain

A new 72-hour transdermal fentanyl matrix patch has been designed, which has a 35%-50% reduction of the absolute fentanyl content compared with other currently available transdermal fentanyl patches that are using the matrix technology. The new patch has previously been shown to be pharmacokinetically bioequivalent to the marketed fentanyl patch. To determine noninferiority in efficacy in cancer patients and to compare safety, a clinical trial comparing the new fentanyl patch with standard oral or transdermal opioid treatment was planned. The design was an open, parallel group, multicenter trial, in which 220 patients were randomized to receive either the fentanyl patch or standard opioid treatment for 30 days. The primary efficacy variable, pain intensity (PI) on a 0-10-point numerical rating scale, was recorded once daily. The primary endpoint was the relative area under the curve of PI expressed as a percentage of the maximum possible PI area under the curve. Any adverse events were recorded; four tolerability endpoints, constipation, nausea, daytime drowsiness, and sleeping disturbances, were assessed daily. Noninferiority was shown; the upper 95% confidence interval limits of the mean difference in relative PI area under the curve between the fentanyl patch and standard opioid treatment were less than 10% for both the intention-to-treat and per-protocol populations. Scores for the tolerability endpoints were similar in the treatment groups. The new fentanyl matrix patch with a lower drug load was found noninferior and as safe as established standard oral and transdermal opioid treatment.

Current concepts in pain management: pharmacologic options for the pediatric, geriatric, hepatic and renal failure patient

This article provides a review for current practice. Strict guidelines are not available on some topics, and they may never be drafted because pain is such a unique individual experience. It is recommended to coordinate care with other medical specialties when patients present with organ dysfunctions or are at the extremes of age. More data are required in the field of pain management, particularly with regard to renal and hepatic dysfunction. In turn, these data serve as a foundation for physicians making practice decisions based on current evidence. Until this is achieved, clinicians must rely on anecdotal evidence and the experiences of others to treat a complex issue: pain.

Advanced formulation design: improving drug therapies for the management of severe and chronic pain

Chronic pain is a condition affecting a vast patient population and resulting in billions of dollars in associated health care costs annually. Sufferers from severe chronic pain often require [correction of requite] twenty-four hour drug treatment through intrusive means and/or repeated oral dosing. Although the oral route of administration is most preferred, conventional immediate release oral dosage forms lead to inconvenient and suboptimal drug therapies for the treatment of chronic pain. Effective drug therapies for the management of chronic pain therefore require advanced formulation design to optimize the delivery of potent analgesic agents. Ideally, these advanced delivery systems provide efficacious pain therapy with minimal side effects via a simple and convenient dosing regime. In this article, currently commercialized and developing drug products for pain management are reviewed with respect to dosage form design as well as clinical efficacy. The drug delivery systems reviewed herein represent advanced formulation designs that are substantially improving analgesic drug therapies.

Clinical experience with transdermal and orally administered opioids in palliative care patients--a retrospective study

BACKGROUND

Transdermal fentanyl is a widely used opioid for the treatment of cancer pain. Simplicity of use and high patient compliance are the main advantages of this opioid. However, based on our clinical experience, transdermal fentanyl is often not efficacious in terminally ill palliative care patients. We thus retrospectively examined the pain management and need for opioid switching in cancer patients admitted to our palliative care unit.

METHODS

Of 354 patients admitted to our palliative care unit from 2004 through 2005, 81 patients were pre-treated with transdermal fentanyl. Demographic and cancer-related data (diagnosis, symptoms, pain score on a numeric rating scale (NRS)), analgesic dose at admission and discharge were compared.

STATISTICS

mean +/- SD, ANOVA, Wilcoxon's test was used for inter-group comparisons, significance P < 0.05, adjusted for multiple testing. Pain scores are given in median (range).

RESULTS

Mean transdermal fentanyl dose at admission was 81.0 +/- 55.8 microg/h. In 79 patients transdermal fentanyl treatment was discontinued. In two patients, analgesic treatment according to WHO I provided sufficient pain relief. The other 77 patients were switched to other opioids: 33 patients to oral morphine and 44 to oral hydromorphone. In patients switched to morphine the dose at discharge (104.7 +/- 89.0 mg) was lower than at admission (165.5 mg morphine equivalence). In patients switched to hydromorphone the dose of 277.8 +/- 255.0 mg morphine equivalent was higher at discharge than at admission (218.2 +/- 131.4 mg morphine equivalence--considering an equianalgesic conversion ratio morphine: hydromorphone = 7.5: 1). Pain scores decreased significantly after opioid rotation (NRS at rest/on exertion: 4 (0-10)/7 (2-10) versus 1 (0-3)/2 (0-5); P < 0.001).

CONCLUSIONS

In the patient group switched to morphine, sufficient pain relief was achieved by lower equianalgesic morphine doses, compared with the doses at admission. In the patient group switched to hydromorphone, higher equianalgesic morphine doses were needed at discharge, considering an equianalgesic conversion ratio of morphine: hydromorphone = 7.5: 1. Patients with far advanced cancer often suffer from sweating and cachexia, which may have negative effects on the absorption of transdermal fentanyl. Opioid switching to oral morphine or hydromorphone was well tolerated and proved to be an efficacious option for cancer pain treatment.

Use of single-drop microextraction for determination of fentanyl in water samples

Fentanyl is a very potent synthetic narcotic analgesic. Because of its strong sedative properties, it has become an analogue of illicit drugs such as heroin. Its unambiguous detection and identification in environmental samples can be regarded as strong evidence of its illicit preparation. In this paper we report application of single-drop microextraction (SDME) for analysis of water samples spiked with fentanyl. Experimental conditions which affect the performance of SDME, for example the nature of the extracting solvent, sample stirring speed, extraction time, ionic strength, and solution pH, were optimized. The method was found to be linear in the concentration range 0.10-10 ng mL(-1). The limits of quantitation and detection of the method were 100 pg mL(-1) and <75 pg mL(-1), respectively. This technique is superior to other sample-preparation techniques because of the simple experimental set-up, short analysis time, high sensitivity, and minimum use of organic solvent.

Fentanyl HCl iontophoretic transdermal system (ITS): clinical application of iontophoretic technology in the management of acute postoperative pain

The fentanyl HCl iontophoretic transdermal system (fentanyl ITS) is a novel patient-controlled analgesia (PCA) system that has been approved in the USA and Europe for the management of acute, moderate-to-severe postoperative pain. This system extends the applicability of transdermal drug delivery to acute pain management, allowing patients to self-administer pre-programmed doses of fentanyl non-invasively through the use of iontophoretic technology. Iontophoresis is the process by which an electric current is used to drive ionized drug molecules across the skin and into the systemic circulation. Results of a recent US clinical trial found the fentanyl ITS to provide pain control equivalent to a standard regimen of morphine i.v. PCA, with a similar incidence of opioid-related adverse events. The fentanyl ITS may offer a number of clinical advantages over existing PCA modalities. Its method of drug delivery avoids the risk of complications from needle-related injuries and infection, and its pre-programmed electronics eliminate the potential for manual programming errors and excessive dosing. In addition, the compact size of the system could enable greater patient mobility following surgery. The fentanyl ITS has the potential to become a valuable option in the management of acute postoperative pain.

Three-cycle fentanyl patch system significantly improves pain control in gynecologic cancer

Pain affects many cancer patients, and in advanced stages of the disease it can significantly affect the quality of their lives. Morphine has long been the 'gold standard' for the treatment of cancer pain. However, its side-effects, particularly sedation and cognitive impairment at high doses, have encouraged the use of 'opioid rotation'. The transdermal fentanyl patch has advantages over oral morphine, with reduced side-effects and increased convenience in practical usage. The side-effects were reduced in patients who changed to the fentanyl patch, but rescue analgesia was often needed because of the decrease of fentanyl release from the patch, especially on the patch replacement day. We have developed a three-cycle fentanyl patch system that provided an appropriate pain control, and this system should be considered for pain relief in cancer patients.

Toward evidence-based prescribing at end of life: a comparative analysis of sustained-release morphine, oxycodone, and transdermal fentanyl, with pain, constipation, and caregiver interaction outcomes in hospice patients

OBJECTIVE

The primary goal of this investigation was to examine selected outcomes in hospice patients who are prescribed one of three sustained-release opioid preparations. The outcomes examined include: pain score, constipation severity, and ability of the patient to communicate with caregivers.

PATIENTS AND SETTINGS

This study included 12,000 terminally ill patients consecutively admitted to hospices and receiving pharmaceutical care services between the period of July 1 and December 31, 2002.

DESIGN

We retrospectively examined prescribing patterns of sustained-release morphine, oxycodone, and transdermal fentanyl. We compared individual opioids on the aforementioned outcome markers, as well as patient gender, terminal diagnosis, and median length of stay.

RESULTS

Patients prescribed a sustained-release opioid had similar average ratings of pain and constipation severity, regardless of the agent chosen. Patients prescribed transdermal fentanyl were reported to have more difficulty communicating with friends and family when compared with patients prescribed either morphine or oxycodone. On average, patients prescribed transdermal fentanyl had a shorter length of stay on hospice as compared with those receiving morphine or oxycodone.

CONCLUSION

There was no difference in observed pain or constipation severity among patients prescribed sustained-release opioid preparations. Patients receiving fentanyl were likely to have been prescribed the medication due to advanced illness and associated dysphagia. Diminished ability to communicate with caregivers and a shorter hospice course would be consistent with this profile. Further investigation is warranted to examine the correlation between a patient's ability to interact with caregivers and pain control achieved.