Switching from reservoir to matrix systems for the transdermal delivery of fentanyl: a prospective, multicenter pilot study in outpatients with chronic pain

Long-acting transdermal drug delivery formulations: Current developments and innovative pharmaceutical approaches

Transdermal administration remains an active research and development area as an alternative route for long-acting drug delivery. It avoids major drawbacks of conventional oral (gastrointestinal side effects, low drug bioavailability, and need for multiple dosing) or parenteral routes (invasiveness, pain, and psychological stress and bio-hazardous waste generated from needles), thereby increasing patient appeal and compliance. This review focuses on the current state of long-acting transdermal drug delivery, including adhesive patches, microneedles, and molecularly imprinted polymeric systems. Each subsection describes an approach including key considerations in formulation development, design, and process parameters with schematics. An overview of commercially available conventional (adhesive) patches for long-acting drug delivery (longer than 24 h), the reservoir- and matrix-type systems under preclinical evaluation, as well as the advanced transdermal formulations, such as the core-shell, nanoformulations-incorporated and stimuli-responsive microneedles, and 3D-printed and molecularly imprinted polymers that are in development, is also provided. Finally, we elaborated on translational aspects, challenges in patch formulation development, and future directions for the clinical advancement of new long-acting transdermal products.

Establishment and Validation of a Transdermal Drug Delivery System for the Anti-Depressant Drug Citalopram Hydrobromide

To enhance the bioavailability and antihypertensive effect of the anti-depressant drug citalopram hydrobromide (CTH) we developed a sustained-release transdermal delivery system containing CTH. A transdermal diffusion meter was first used to determine the optimal formulation of the CTH transdermal drug delivery system (TDDS). Then, based on the determined formulation, a sustained-release patch was prepared; its physical characteristics, including quality, stickiness, and appearance, were evaluated, and its pharmacokinetics and irritation to the skin were evaluated by applying it to rabbits and rats. The optimal formulation of the CTH TDDS was 49.2% hydroxypropyl methyl cellulose K100M, 32.8% polyvinylpyrrolidone K30, 16% oleic acid-azone, and 2% polyacrylic acid resin II. The system continuously released an effective dose of CTH for 24 h and significantly enhanced its bioavailability, with a higher area under the curve, good stability, and no skin irritation. The developed CTH TDDS possessed a sustained-release effect and good characteristics and pharmacokinetics; therefore, it has the potential for clinical application as an antidepressant.

Case Reports of Transdermal Fentanyl Patch Administration Difficulties in Cancer Patients with Excess Sweating

(Case 1) A 45-year-old male was diagnosed with prostate cancer. Treatment was administered using bicalutamide and leuprorelin acetate, while a transdermal fentanyl (TDF) was applied for pain relief. However, TDF continued to peel off owing to excessive sweating, even when reinforced by a protective layer. As such, TDF was discontinued and pain control was initiated using other medicines. Sweating occurred irregularly because of hot flashes, approximately four to five times per day. (Case 2) A 37-year-old male was diagnosed with a malignant thymoma and sacral metastasis. For analgesic control, etodolac tablets, carbamazepine tablets, and TDF were administered. Subsequently, the dose of the TDF was gradually increased, but the analgesic effect was low; thus, fentanyl blood concentration was measured. The measurements showed that even higher TDF doses did not increase fentanyl blood levels. During this period, full body sweating began to occur to a large extent due to unknown causes, and it was thought that the absorption of fentanyl decreased. When using a TDF, it is necessary to monitor patients for any sweating during treatment, while also considering changes in medication in some cases. This should promote the maintenance and improvement of the quality of life of the affected patients.

Glucose-insulin-potassium alleviates uterine cramping pain following cesarean delivery: A randomized, controlled trial

Objectives

To explore the effect of glucose-insulin-potassium (GIK) therapy on uterine cramping pain (UCP) following cesarean delivery (CD).

Design

Single-center, randomized controlled study.

Setting

Second Affiliated Hospital of Army Medical University, Chongqing, China.

Participants

A total of 140 women, aged 20-40 years, who underwent CD with a transverse incision were randomly assigned to the GIK (P) or control (C) groups in a 1:1 ratio.

Interventions

GIK was intravenously administered to patients in Group P. Patients in Group C received normal saline (NS). After umbilical cord clamping, oxytocin was administered intravenously. The same GIK and NS regimens were administered on postoperative days 1 and 2, followed by oxytocin 10 min later.

Primary and secondary outcome measures

Following oxytocin administration, UCP was assessed using the visual analog scale (VAS), and the maximum VAS score (primary outcome) was recorded.

Results

Patients in Group P had significantly lower maximum VAS scores than those in Group C on postoperative days 1 (38.4 ± 21.1 vs. 52.3 ± 20.8, p < 0.001) and 2 (10 [0,30] vs. 30.5 [8.75,50], p < 0.001). Group P patients also had shorter pain duration on postoperative day 1 (39.6 ± 19.5 min vs. 50.6 ± 18.2 min, p = 0.001). Group P patients had a lower incidence of inadequate analgesia of UCP than Group C on days 1 (45.5% vs. 74.2%, p < 0.001) and 2 (10.6% vs. 47.0%, p < 0.001); the RRs for experiencing inadequate analgesia for UCP postpartum in Group P patients was 0.612 (95% CI: 0.454-0.826, p < 0.001) on day 1 and 0.226 (95% CI: 0.107-0.476, p < 0.001) on day 2. The absolute risk reduction (ARR) was 28.7%; thus number needed to treat (NNT) was 3 after rounding up. A subgroup analysis demonstrated that Group P patients undergoing repeat CD had lower maximum VAS scores for UCP on both postoperative days 1 and 2.

Conclusion

Our findings suggest that GIK can relieve UCP and shorten its duration. Our results provide information to facilitate the development of novel approaches for managing UCP.Clinical Trial Registration: This study was approved by the Medical Ethics Committee of Second Affiliated Hospital of Army Medical University (2020-109-01, 19/11/2020) and registered in the Chinese Clinical Trial Registry (http://www.chictr.org.cn, ChiCTR2100041607,01/01/2021).

Impact of expanded strong opioid availability on opioid prescription patterns in patients with cancer: A population-wide cohort study in Taiwan

Background One of the major barriers to adequate cancer pain management in Taiwan is the limited prescription options regarding strong opioids. Internationally recommended strong opioids, including oxycodone and hydromorphone, were not introduced in Taiwan until late 2014. We analysed the patterns in opioid prescription for cancer pain management, after the introduction of new opioid options. Methods All inpatient and outpatient clinical visits from January 1, 2012, to December 31, 2017, with the diagnosis of cancer and the analgesic prescriptions were collected from the database of National Health Insurance, Taiwan, and analysed. Opioids were grouped into strong opioids, weak opioids, and guideline non-recommended opioids. Findings A total of 1, 292, 905 patients with cancers were included. Approximately 50% of patients used analgesics, 50% of which were opioids; the proportions were stable during the study period. The annual cumulative opioid use per patient (defined daily dose, DDD) significantly decreased from 36•41±102•59 (Mean±SD) in 2012 to 32•42±100•99 in 2017 (p < •001). The annual cumulative strong opioid use per patient increased significantly from 17•54±89•23 in 2012 to 19•28±94•97 in 2017 (+9•90%, p < •001). In parallel, the annual cumulative weak opioids use per patient decreased from 18•64±40•81 in 2012 to 13•04±26•79 in 2017 (-30•04%, p < •001). Among extended-release strong opioids, the use of transdermal fentanyl significantly decreased after oxycodone and hydromorphone were introduced (p < •001). Interpretation Increased therapeutic options in strong opioid prescriptions led opioid prescription patterns to evolve towards international cancer pain management guidelines. In addition, increased accessibility to a wider range of different strong opioids may facilitate more efficient opioid titration and rotation - and thus decrease, not increase, the opioid usage. Funding This study was supported by Ministry of Science and Technology, Taiwan (MOST-106-2314-B-002-213 and MOST-108-2314-B-002-072-MY3), Ministry of Health and Welfare, Taiwan (MOHW109-TDU-B-211-114002), National Taiwan University Hospital, Taipei, Taiwan (NTUH-103-002314 and NTUH. 105-S2954), and National Center of Excellence for Clinical Trial & Research, National Taiwan University Hospital, Taipei, Taiwan (NCTRC201208 and NCTRC201603).

The use of rotation to fentanyl in cancer-related pain

Pain is commonly diagnosed with respect to cancer and heart diseases, being a major symptom in most neoplastic diseases. Uncontrolled pain leads to a decrease in the quality of life and an increase in the morbidity of the patient. Opioids represent the best analgetic supportive therapy and are frequently used in patients suffering from cancer and experiencing a high level of pain. Opioid treatment starts with a gradual titration of the dose until the minimum effective dose and the maximum tolerated dose are determined. Opioid rotation refers to the switch from one opioid to another in order to get a better response to analgetic therapy and reduce side effects. Fentanyl therapy is recommended to be continued during chemotherapy, radiotherapy, or in the case of surgical intervention. Rotation to fentanyl patches is an efficient and elegant solution for cancer patients, with reduced side effects. Opioid rotation, especially to fentanyl, was shown to increase the quality of life in patients with malignant disease. Finally, rotation to fentanyl is also advantageous from an economic point of view.

Using skin for drug delivery and diagnosis in the critically ill

Skin offers easy access, convenience and non-invasiveness for drug delivery and diagnosis. In principle, these advantages of skin appear to be attractive for critically ill patients given potential difficulties that may be associated with oral and parenteral access in these patients. However, the profound changes in skin physiology that can be seen in these patients provide a challenge to reliably deliver drugs or provide diagnostic information. Drug delivery through skin may be used to manage burn injury, wounds, infection, trauma and the multisystem complications that rise from these conditions. Local anaesthetics and analgesics can be delivered through skin and may have wide application in critically ill patients. To ensure accurate information, diagnostic tools require validation in the critically ill patient population as information from other patient populations may not be applicable.

Serum concentration of fentanyl during conversion from intravenous to transdermal administration to patients with chronic cancer pain

BACKGROUND

To the best of our knowledge, there have been no reports on the pharmacokinetics and pharmacodynamics during the conversion from continuous intravenous infusion (CII) to transdermal fentanyl administration. The primary objective of the present study was to clarify the pharmacokinetic characteristics during this conversion. A secondary objective was to identify an association between serum albumin and the absorption of fentanyl from the transdermal patch.

METHODS

A prospective study was conducted from February 2010 to August 2011 that enrolled 19 patients with chronic cancer pain. Patients were classified into 2 study groups according to body mass index and albumin level. All patients received the conversion from CII to transdermal fentanyl using a 2-step taper of CII over 6 hours. Comparisons of efficacy, toxicity, and serum fentanyl concentrations between study groups were analyzed at baseline, 3, 6, 9, 12, 15, 18, and 24 hours after initiation of the conversion.

RESULTS

The dose-adjusted serum fentanyl concentrations for all patients were significantly decreased at 15 to 24 hours after conversion compared with baseline, although pain intensity and the number of rescue events remained stable during the conversion. The dose-adjusted serum fentanyl concentrations at 9 to 24 hours were significantly reduced in the low albumin group compared with the normal albumin group (P<0.05).

CONCLUSIONS

Our study demonstrated that the dose-adjusted serum fentanyl concentrations remained relatively stable, and pain intensity and the number of rescue events remained stable during conversion. Hypoalbuminemia was strongly associated with poor absorption of transdermally administered fentanyl.

Assessment of extended-release opioid analgesics for the treatment of chronic pain

Approximately 3.8 million patients annually receive extended-release (ER) or long-acting opioid prescriptions in the outpatient setting, around half of which are written by primary care physicians. Compared with short-acting, immediate-release (IR) formulations, ER and oral long-acting opioid analgesics are associated with clinical advantages, such as extended periods of time during which drug plasma levels are within the therapeutic range, decreased peak-to-trough fluctuations, and prolonged analgesia over the dosing period. Additionally, ER opioids offer a more convenient, less frequent dosing regimen to chronic pain patients who are often taking several concomitant medications. The increased utilization of ER opioids has been accompanied by a rise in the misuse and abuse of these formulations. Certain pharmacokinetic parameters (e.g., longer time to maximum drug plasma concentration, lower maximum drug plasma concentration) may decrease the abuse potential of intact ER opioids by limiting the positive subjective and reinforcing effects relative to IR formulations. Putative abuse-deterrent formulations have also recently been introduced to impede physical manipulation of these formulations, or reduce the harm resulting from such behavior. Such formulations may represent an incremental advance to reduce non-oral forms of abuse. This article reviews the pharmacokinetic profiles and abuse-deterrent features of newer ER opioid analgesics for the treatment of moderate to severe chronic pain.

Pharmacokinetics, Tolerability, and Performance of a Novel Matrix Transdermal Delivery System of Fentanyl Relative to the Commercially Available Reservoir Formulation in Healthy Subjects

A novel transdermal formulation of fentanyl-containing dipropylene glycol droplets dispersed in a silicone matrix with a rate-controlling membrane was developed. Healthy male subjects (n = 24) received repeated 72-hour applications of fentanyl (50 mug/h) as the novel matrix and the conventional reservoir formulations in a randomized, 2-way crossover study. Blood samples were collected, and serum concentrations of fentanyl were assayed using liquid chromatography with mass spectrometry detection. The mean area under the curve (AUCtau) and peak concentrations (C(max)) of the matrix formulation were 84 838 pg.h/mL and 1680 pg/mL, respectively. Ratio and 90% confidence intervals of AUCtau and C(max) between the 2 formulations were within 80% to 125%. Adherence of the matrix formulation was higher than the reservoir formulation (62.5 vs 56.2%, P < .0001), without affecting skin irritation. Vital signs and adverse events of the 2 formulations were similar in nature and frequency. The novel matrix formulation displayed enhanced adherence and resulted in similar pharmacokinetics and tolerability as the reservoir formulation.

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.

Recent advances in the pharmaceutical management of pain

Pain is an unpleasant sensory and emotional experience for patients. Management of pain is the most frequent issue encountered by clinicians and treatment is usually with pharmacological therapy. This review discusses recent pharmaceutical advances in pain management with respect to new modes of analgesic delivery, as well as new analgesic agents and adjuvants that are currently being investigated for their analgesic properties. New modes of administration include transdermal delivery in the form of skin patches, transmucosal delivery, inhalational administration, various patient-controlled devices and extended-release analgesic formulations. Up-to-date research is presented on classical analgesics, such as opioids, anti-inflammatory agents, including cyclo-oxygenase-2 inhibitors and paracetamol (acetaminophen), local anesthetics and ketamine. In addition, newer agents such as antidepressants and antiepileptic drugs as well as medicinal cannabinoids are discussed. As our understanding of the multiple pain pathways involved in the pathogenesis of pain expands, further compounds with analgesic properties will be developed.

Transdermal opioids for cancer pain

PURPOSE OF REVIEW

Cancer patients with moderate-to-severe pain require opioids for analgesia. Whereas early guidelines recommend oral morphine as the 'drug of choice', newer synthetic opioids can be given by a reliable and effective nonoral transdermal route. We examine the mode of action of transdermal patches and we review the evidence on two drugs, which are currently available in this formulation - buprenorphine and fentanyl - covering physicochemical characteristics and pharmacokinetics of the patches, clinical efficacy data and adverse effects.

RECENT FINDINGS

Both buprenorphine and fentanyl possess ideal characteristics for transdermal delivery, being small molecules with high lipophilicity. Studies of buprenorphine patches show benefits but there is poor randomized controlled trial evidence comparing them with oral opioids. Fentanyl patches have been used for longer and have a larger body of evidence supporting their use, with data to suggest improved pain relief and reduced opioid side effects compared with sustained release oral morphine. Patients who have used both oral morphine and transdermal fentanyl express a preference for the patch drug.

SUMMARY

Transdermal buprenorphine and fentanyl are now established for moderate-to-severe cancer pain. There is still a need for further comparative studies with other opioids, especially for buprenorphine.

Six- versus 12-h conversion method from intravenous to transdermal fentanyl in chronic cancer pain: a randomized study

PURPOSE

The objective of the present prospective study was to compare the safety and efficacy of a 12-h method to a 6-h method in chronic cancer pain management.

MATERIALS AND METHODS

Randomized, prospective clinical trial was conducted between December 2007 and June 2009, enrolling 90 patients with chronic cancer pain. Patients with chronic cancer pain were randomly assigned to the conversion from continuous intravenous infusion to transdermal fentanyl using two-step taper of the continuous intravenous infusion in 12 h (12-h method) or the conversion in 6 h (6-h method). The parameters assessed in the present study included pain intensity (on a scale of 0 to 10) and bolus use frequency, and the adverse effects were assessed with National Cancer Institute Common Terminology Criteria for Adverse Events version 3.

RESULTS

Pain intensity and the number of boluses during conversion remained stable in both arms. The incidence of adverse events was 25.6% in the 12-h method group and 2.3% in the 6-h method group (95% confidence interval, 0.01-0.55; p = 0.002). Adverse events occurred in four patients at 6-12 h, five patients at 12-18 h, two patients at 18-24 h, and one patient at 24-48 h after application.

CONCLUSIONS

Excellent safety profile and sustained efficacy are shown for the 6-h conversion method.

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.

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.

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.

Epidemiology of regular prescribed opioid use: results from a national, population-based survey

Chronic pain occurs commonly and accounts for significant suffering and costs. Although use of opioids for treatment of chronic pain is increasing, little is known about patients who use opioids regularly. We report data from the second wave of the Healthcare for Communities survey (2000-2001), a large, nationally representative household survey. We compared regular users of prescription opioids to nonusers of opioids and calculated the percentage of individuals within a given demographic or disease state that reported chronic opioid use. Approximately 2% of the 7,909 survey respondents reported use of opioid medications for at least a month, which the Healthcare for Communities survey defined as "regular use." Opioid users were more likely than nonusers to report high levels of pain interference with their daily lives and to rate their health as fair or poor. Arthritis and back pain were the most prevalent chronic, physical health conditions among users of opioids, with 63% of regular users of opioids reporting arthritis and 59% reporting back pain. The majority of regular users of opioids had multiple pain conditions (mean=1.9 pain conditions). Regular opioid users appear to have an overall lower level of health status and to have multiple, chronic physical health disorders.

Rhythmic pattern in pain and their chronotherapy

Pain control is one of the most important therapeutic priorities; nonetheless, inadequate pain relief remains a significant health care issue. Thus, it is important to determine whether the analgesic effect can be improved by using the chronopharmacological approach. This paper reviews the data on the rhythmic patterns in pain level and their chronotherapy. It underlines the major issues and problems related to the development of chronotherapeutic strategies, and it examines emerging aspects of new drug-delivery systems for achieving such.

Transdermal fentanyl in childhood and adolescence: a comprehensive literature review

The recently introduced fentanyl transdermal therapeutic system (TTS) with a drug release rate of 12.5 microg/h matches the lower dosing requirements of cancer pain control in children. It is likely that fentanyl TTS will be used in pediatrics with increasing frequency. We compiled the published evidence on pediatric applications of this drug formulation to help physicians get the most benefit from its use. Within this systematic review, a total of 11 observational clinical or pharmacokinetic studies were identified. There are no pediatric randomized or controlled cohort studies. Pharmacokinetic studies poorly described time-concentration profiles after application. The time to reach steady-state serum drug concentrations seems to be longer, clearance (expressed as liters per kilogram per hour) higher, and elimination half-life shorter in children than in adults. There are no fundamental differences in effect or profile of adverse effects compared with adults. Fentanyl TTS may be associated with less constipation compared with morphine use. Frequently, pediatric patients need supplemental mechanical fixation of the fentanyl TTS by means of medical tape. Younger patients tend to have a higher fentanyl requirement when referenced to body weight. Both parents and medical professionals are satisfied with fentanyl TTS to a higher degree than with individual analgesic pretreatment regimens. Fentanyl TTS is a promising option for chronic pain control in children. An approximate conversion factor of 45 mg/day oral morphine to 12.5 microg/h fentanyl TTS is used for initial therapy dose estimation in children receiving long-term morphine therapy. This is conservatively low to avoid respiratory depression. Daily oral morphine equivalent dose should be at least 30 mg/d before fentanyl TTS therapy is started with 12.5 microg/h. Evidence for superiority of fentanyl TTS treatment above conventional opioid administration is both scarce and of low quality.

PERSPECTIVE

The article gives a comprehensive overview of all pediatric data concerning the fentanyl TTS. Children may take longer to reach steady-state fentanyl serum concentrations than adults, and younger children may require higher doses referenced to body weight than older children or adults. Consequently, there is a need to provide sufficient medication in the phase of therapy initiation to prevent breakthrough pain. The 72-hour dosing schedule recommended by the manufacturers may not be applicable to children because of poor patch adhesiveness. The authors suggest to ensure firm fixation of the fentanyl TTS with additional medical tape if necessary and to change the fentanyl TTS after 48 hours. Transdermal fentanyl in children may exhibit fewer side effects when compared with other opioids, especially constipation. Randomized studies are urgently needed to definitively answer this question.

Validated GC–MS analysis for the determination of residual fentanyl in applied Durogesic® reservoir and Durogesic® D-Trans® matrix transdermal fentanyl patches

The method development and validation characteristics are described of a simple gas chromatographic-mass spectrometric (GC-MS) analytical procedure to determine residual fentanyl in used Durogesic reservoir patches and Durogesic D-Trans matrix technology based systems to estimate the actual rate of transdermal fentanyl delivered in individual patients. The sample preparation protocol constituting a saline based extraction of sets of new patches of each nominal dose available, resulted in fentanyl extraction recoveries to increase steadily as a function of increasing extraction time. For the reservoir type transdermal therapeutic system (TTS), fentanyl extraction efficiencies at equilibrium (16 h) ranged from approximately 60% (100-microg/h TTS) to 95% (25-microg/h TTS), whereas for the matrix type system considerable lower recoveries were demonstrated for the highest nominal dose rates (35%-52%), while reaching 90% for the 25-microg/h system. For the latter type of fentanyl TTS, an optimized methanol based extraction protocol yielded virtually quantitative fentanyl recoveries for each matrix patch nominal dose level at substantially shorter extraction periods (15 min). The GC-MS analytical method using selected ion monitoring (SIM) and deuterated fentanyl as internal standard was shown to be adequately selective with regard to the presence of other compounds in the Durogesic patches. It was further demonstrated that the developed analytical protocols provided highly reproducible and accurate estimates of the initial fentanyl content of each patch type at all available nominal doses, with coefficients of variation and relative errors generally below 10%. These advantageous assay validation characteristics can be further transposed to the application of residual fentanyl level estimates in used patches, provided that with each batch of samples also a set of new TTSs with equal dose is assayed to perfectly mimic extraction phenomena. Finally, the presented GC-MS analytical protocol was successfully applied for the determination of residual fentanyl in a subset of 57 reservoir type patches obtained from four palliative patients.

Comparative bioequivalence study between a novel matrix transdermal delivery system of fentanyl and a commercially available reservoir formulation

AIM

To determine the pharmacokinetics, safety and performance of a novel matrix formulation of fentanyl.

METHODS

Transdermal fentanyl was administered as the novel matrix and the Durogesic reservoir formulations (24 subjects, 100 microg h(-1)) in a randomized, fully replicate, four-way crossover study. Serum concentrations of fentanyl were assayed by LC/MS/MS. Pharmacokinetic parameters of fentanyl and performance (adherence and skin irritability) were evaluated.

RESULTS

Test/reference ratio (90% confidence intervals) for AUC(0-t), AUC(inf) and C(max) were 105.5% (99.4, 112.0), 105.3% (99.3, 111.6) and 111.4% (100.4, 123.6), respectively. Adherence and skin irritability results of the two formulations were similar.

CONCLUSION

The two formulations are expected to result in similar efficacy for the management of severe pain.

Randomized trial comparing polymer-coated extended-release morphine sulfate to controlled-release oxycodone HCl in moderate to severe nonmalignant pain

OBJECTIVE

To assess the long-term efficacy, tolerability and safety of polymer-coated extended-release morphine sulfate (P-ERMS) (KADIAN) compared with controlled-release oxycodone HCl (CRO) (OxyContin) in treating chronic, nonmalignant, moderate to severe pain in a community-based outpatient population.

DESIGN

Phase IV, prospective, randomized, open-label.

PARTICIPANTS

Adults (N = 112) with chronic, nonmalignant, moderate to severe pain with visual numeric scale (VNS) scores > or = 4 (0 = no pain; 10 = worst pain).

INTERVENTIONS

Patients were randomized to receive either P-ERMS once-daily (QD) dosing or CRO twice-daily (BID) dosing for a 24-week treatment period. Upward titration of dose and switching P-ERMS to BID or CRO to thrice-daily (TID) dosing was allowed Weeks 2-24.

MAIN OUTCOME MEASURES

Quality of life (Physical [PCS] and Mental [MCS] Component Summary scores of the SF-36v2 Health Survey), pain and sleep scores (0-10), and patient and clinician assessments of current therapy (-4 to +4).

RESULTS

Patients in both treatment groups experienced significant improvements in PCS scores (P-ERMS, +2.6; CRO, +3.1; p < 0.05 vs. baseline); patients taking CRO also demonstrated improvements in MCS scores (+4.7, p < 0.05 vs. baseline). Both groups attained significant reductions from baseline to 24 weeks in pain (P-ERMS, -2.0; CRO, -1.4; p < or = 0.001 vs. baseline); the reduction with P-ERMS was clinically meaningful (as defined by at least a 2-point reduction in VNS score). Patients attained significant improvement in sleep scores (P-ERMS, -2.6; CRO, -1.6; p < 0.001 vs. baseline; p < 0.05, P-ERMS vs. CRO). At Week 24, both groups indicated significantly increased patient (P-ERMS, +2.6; CRO, +1.7; p < 0.001 vs. baseline) and clinician (P-ERMS, +4.0; CRO, +3.1; p < 0.001 vs. baseline) global assessments of therapy. After 24 weeks, all patients on P-ERMS were dosing within the FDA-approved frequencies (65% QD, 35% BID); 56% of patients on CRO dosed BID, but 38% dosed TID and 6% dosed four times daily (QID). Most common adverse events were constipation, nausea, and somnolence, with no significant difference between treatment groups.

CONCLUSIONS

P-ERMS and CRO both relieved chronic nonmalignant pain in this community-based population; however, patients taking P-ERMS dosed in accordance with FDA-approved frequencies (QD/BID); 44% of those taking CRO dosed more frequently (TID/QID).