Benefit-Risk Assessment of Transdermal Fentanyl for the Treatment of Chronic Pain

Improving Transdermal Fentanyl Prescribing Practices Using Electronic Medical Record

Background: Transdermal (TD) fentanyl has a unique place in pain management that is not universally understood, thereby raising concerns for patient safety. This project aimed to improve TD fentanyl prescribing practices through an ordering algorithm in the electronic medical record (EMR). Measures: The main outcome measure was the percentage of erroneous TD fentanyl orders after EMR order implementation. Intervention: After a retrospective chart review to assess TD fentanyl orders, a root cause analysis led to the development and introduction of an enhanced ordering algorithm in EMR in January 2023, accompanied by pharmacy education. Outcomes: After the intervention, a review of TD fentanyl orders over five months showed a reduction in inappropriate ordering from 42.5% to 15.2%. Conclusions: Standardized EMR order sets, combined with provider education, hold promise for enhancing the quality and safety of chronic pain management with TD fentanyl.

A qualitative evaluation of a fentanyl patch safer supply program in Vancouver, Canada

BACKGROUND

The ongoing overdose crisis in Canada has prompted efforts to increase access to a "safer supply" of prescribed alternatives to the unregulated drug supply. While safer supply programs predominantly distribute hydromorphone tablets, the Safer Alternatives for Emergency Response (SAFER) program in Vancouver, Canada offers a range of prescribed alternatives, including fentanyl patches. However, little is known about the effectiveness of fentanyl patches as safer supply. Drawing on the perspectives and experiences of program participants, we sought to qualitatively evaluate the effectiveness of the SAFER fentanyl patch program in meeting its intended aims, including reducing risk of overdose by decreasing reliance on the unregulated drug supply.

METHODS

As part of a larger mixed-methods evaluation of SAFER, semi-structured qualitative interviews were conducted with 17 fentanyl patch program participants between February 2022 and April 2023. Thematic analysis of interview data focused on program engagement, experiences, impacts, and challenges.

RESULTS

The flexible program structure, including lack of need for daily dispensation, the extended missed dose protocol, and community pharmacy patch distribution fostered engagement and enhanced autonomy. Improved management of withdrawal symptoms and cravings due to steady transdermal dosing led to reduced unregulated drug use and overdose risk. Participants also experienced economic benefits and improvements in overall health and quality of life. However, skin irritation and patch adhesion issues were key barriers to program retention.

CONCLUSION

Our findings demonstrate the value of including fentanyl patch safer supply in the substance use continuum of care and offer insights for innovations in delivery of this intervention.

Continuous flow reactions in the preparation of active pharmaceutical ingredients and fine chemicals

Herein, we present an overview of continuous flow chemistry, including photoflow and electroflow technologies in the preparation of active pharmaceutical ingredients (APIs) and fine chemical intermediates. Examples highlighting the benefits and challenges associated with continuous flow processes, mainly involving continuous thermal, photo- and electrochemical transformations, are drawn from the relevant literature, especially our experience and collaborations in this area, with emphasis on the synthesis and prospective scale-up.

Assessment of Drug-Drug Interaction Risk Between Intravenous Fentanyl and the Glecaprevir/Pibrentasvir Combination Regimen in Hepatitis C Patients Using Physiologically Based Pharmacokinetic Modeling and Simulations

INTRODUCTION

An unsafe injection practice is one of the major contributors to new hepatitis C virus (HCV) infections; thus, people who inject drugs are a key population to prioritize to achieve HCV elimination. The introduction of highly effective and well-tolerated pangenotypic direct-acting antivirals, including glecaprevir/pibrentasvir (GLE/PIB), has revolutionized the HCV treatment landscape. Glecaprevir is a weak cytochrome P450 3A4 (CYP3A4) inhibitor, so there is the potential for drug-drug interactions (DDIs) with some opioids metabolized by CYP3A4, such as fentanyl. This study estimated the impact of GLE/PIB on the pharmacokinetics of intravenous fentanyl by building a physiologically based pharmacokinetic (PBPK) model.

METHODS

A PBPK model was developed for intravenous fentanyl by incorporating published information on fentanyl metabolism, distribution, and elimination in healthy individuals. Three clinical DDI studies were used to verify DDIs within the fentanyl PBPK model. This model was integrated with a previously developed GLE/PIB PBPK model. After model validation, DDI simulations were conducted by coadministering GLE 300 mg + PIB 120 mg with a single dose of intravenous fentanyl (0.5 µg/kg).

RESULTS

The predicted maximum plasma concentration ratio between GLE/PIB + fentanyl and fentanyl alone was 1.00, and the predicted area under the curve ratio was 1.04, suggesting an increase of only 4% in fentanyl exposure.

CONCLUSION

The administration of a therapeutic dose of GLE/PIB has very little effect on the pharmacokinetics of intravenous fentanyl. This negligible increase would not be expected to increase the risk of fentanyl overdose beyond the inherent risks related to the amount and purity of the fentanyl received during recreational use.

Novel Opioid Analgesics for the Development of Transdermal Opioid Patches That Possess Morphine-Like Pharmacological Profiles Rather Than Fentanyl: Possible Opioid Switching Alternatives Among Patch Formula

Transdermal fentanyl is widely used in the treatment of severe pain because of convenience, safety, and stable blood concentrations. Nevertheless, patients often develop tolerance to fentanyl, necessitating the use of other opioids; transdermal buprenorphine patch is widely used as an analgesic agent, though available formulation does not provide comparable analgesic effect as transdermal fentanyl patch. Opioids bind to the opioid receptor (OR) to activate both G protein–mediated and β-arrestin–mediated pathways. We synthesized morphine-related compounds with high transdermal absorbability (N1 and N2) and evaluated their OR activities pharmacologically in comparison with fentanyl and morphine.

In-Plane Si Microneedles: Fabrication, Characterization, Modeling and Applications

Microneedles are getting more and more attention in research and commercialization since their advancement in the 1990s due to the advantages over traditional hypodermic needles such as minimum invasiveness, low material and fabrication cost, and precise needle geometry control, etc. The design and fabrication of microneedles depend on various factors such as the type of materials used, fabrication planes and techniques, needle structures, etc. In the past years, in-plane and out-of-plane microneedle technologies made by silicon (Si), polymer, metal, and other materials have been developed for numerous biomedical applications including drug delivery, sample collections, medical diagnostics, and bio-sensing. Among these microneedle technologies, in-plane Si microneedles excel by the inherent properties of Si such as mechanical strength, wear resistance, biocompatibility, and structural advantages of in-plane configuration such as a wide range of length, readiness of integration with other supporting components, and complementary metal-oxide-semiconductor (CMOS) compatible fabrication. This article aims to provide a review of in-plane Si microneedles with a focus on fabrication techniques, theoretical and numerical analysis, experimental characterization of structural and fluidic behaviors, major applications, potential challenges, and future prospects.

Opioid-induced adrenal insufficiency in transdermal fentanyl treatment: a revisited diagnosis in clinical setting

Opioids are widely used for treatment of acute and chronic pain. However, opioids have several well-known clinical adverse effects such as constipation, nausea, respiratory depression and drowsiness. Endocrine dysfunctions are also opioid-induced adverse effects but remain under-diagnosed in clinical settings, especially opioid-induced adrenal insufficiency (OIAI). A 46-year-old woman was treated with transdermal fentanyl at a dose of 90-120 mg daily morphine milligram equivalent for non-malignant chronic pain for four years. Fatigue, loss of appetite and decrease in vitality began about two years after starting fentanyl. Subsequently, constipation and abdominal pain appeared and became worse, which led to suspicion of adrenal insufficiency. Clinical diagnosis of OIAI was established based on laboratory findings of secondary adrenal insufficiency, including corticotropin-releasing hormone stimulation test, clinical history of long-term fentanyl use, and exclusion of other hypothalamic-pituitary diseases. Oral corticosteroid replacement therapy was unable to relieve her abdominal pain and constipation; opioid-rotation and dose-reduction of fentanyl were not feasible because of her persistent pain and severe anxiety. While her clinical course clearly suggested that long-term, relatively high-dose transdermal fentanyl treatment may have contributed to the development of secondary adrenal insufficiency, the symptoms associated with OIAI are generally non-specific and complex. Together with under-recognition of OIAI as a clinical entity, the non-specific, wide range of symptoms can impede prompt diagnosis. Thus, vigilance for early symptoms enabling treatments including corticosteroid replacement therapy is necessary for patients taking long-term and/or high dose opioid treatment.

Trends in the Prescription of Strong Opioids for Chronic Non-Cancer Pain in Primary Care in Catalonia: Opicat-Padris-Project

In chronic non-cancer pain (CNCP), evidence of the effectiveness of strong opioids (SO) is very limited. Despite this, their use is increasingly common. To examine SO prescriptions, we designed a descriptive, longitudinal, retrospective population-based study, including patients aged ≥15 years prescribed SO for ≥3 months continuously in 2013–2017 for CNCP in primary care in Catalonia. Of the 22,691 patients included, 17,509 (77.2%) were women, 10,585 (46.6%) were aged >80 years, and most had incomes of <€18,000 per year. The most common diagnoses were musculoskeletal diseases and psychiatric disorders. There was a predominance of transdermal fentanyl in the defined daily dose (DDD) per thousand inhabitants/day, with the greatest increase for tapentadol (312% increase). There was an increase of 66.89% in total DDD per thousand inhabitants/day for SO between 2013 (0.737) and 2017 (1.230). The mean daily oral morphine equivalent dose/day dispensed for all drugs was 83.09 mg. Transdermal fentanyl and immediate transmucosal release were the largest cost components. In conclusion, there was a sustained increase in the prescription of SO for CNCP, at high doses, and in mainly elderly patients, predominantly low-income women. The new SO are displacing other drugs.

Fentanyl transdermal patches: Extraction and evaluation of a novel disposal method using NarcX®

Currently, there is no known commercially available product for disposing of used fentanyl transdermal patches. To eliminate the potential for harm and abuse, a proper disposal method is needed-one that neutralizes the dangerous amount of residual fentanyl that remains after therapeutic use of the fentanyl patch. The patent-pending liquid solution of activated carbon, known as NarcX^® , was investigated as a potential fentanyl adsorbing agent. In order to determine the amount of fentanyl remaining after a patch is treated with NarcX^® , here, we utilized hexanes to first dissolve the patch adhesive and then followed with liquid-liquid extraction with methanol to recover the fentanyl. Using liquid chromatography coupled to tandem mass spectrometry (LC/MS-MS), the extracts obtained with this method yielded between 85% and 117% recovery of fentanyl from new and unused patches. Further optimization of this method allowed for a quantitative evaluation of NarcX^® -treated fentanyl patches. 100 µg/h Apotex brand fentanyl patches were exposed to NarcX^® for 1, 24, 48, and 72 h. NarcX^® was shown to adsorb fentanyl from the patches with varying degrees of success, demonstrating an average of 66.98 ± 0.75% fentanyl adsorption after 72 h. These findings suggest that more work is needed to successfully neutralize the fentanyl patches in their entirety using NarcX^® ; however, this work does demonstrate proof of concept.

Fentanyl use disorder characterized by unprescribed use of transdermal patches: a case report

BACKGROUND

Fentanyl is a synthetic opioid with analgesic potency 75-100 times higher than that of morphine, and its analgesic effect is used for pain treatment, mostly in cancer patients. Using fentanyl patches may reduce misuse potential due to the transdermal route of administration, long-acting action, sustained release delivery property, and maintenance of steady-state serum concentration of the drug. Although there have been reports of transdermal fentanyl patches (TFPs) misuse via transmucosal, trans-nasal, intravenous, and oral routes of administration, fentanyl use disorder via the transdermal route is very rare.

CASE

In this case report, we present a patient with a history of substance use disorder who developed fentanyl use disorder via transdermal route after using unprescribed TFP in order to quit opium gum. The CARE guidance was followed in the preparation of this case report.

CONCLUSION

The risk of use disorder may be higher, especially in individuals with a history of substance use disorders. This risk should be taken into account when clinicians prescribe this medication.

Transdermal drug delivery systems for fighting common viral infectious diseases

Transdermal drug delivery systems (TDDS) have many advantages and represent an excellent alternative to oral delivery and hypodermic injections. TDDS are more convenient and less invasive tools for disease and viral infection treatment, prevention, detection, and surveillance. The emerging development of microneedles for TDDS has facilitated improved skin barrier penetration for the delivery of macromolecules or hydrophilic drugs. Microneedle TDDS patches can be fabricated to deliver virus vaccines and potentially provide a viable alternative vaccine modality that offers improved immunogenicity, thermostability, simplicity, safety, and compliance as well as sharp-waste reduction, increased cost-effectiveness, and the capacity for self-administration, which could improve vaccine distribution. These advantages make TDDS-based vaccine delivery an especially well-suited option for treatment of widespread viral infectious diseases including pandemics. Because microneedle-based bioassays employ transdermal extraction of interstitial fluid or blood, they can be used as a minimally invasive approach for surveying disease markers and providing point-of-care (POC) diagnostics. For cutaneous viral infections, TDDS can provide localized treatment with high specificity and less systemic toxicity. In summary, TDDS, especially those that employ microneedles, possess special attributes that can be leveraged to reduce morbidity and mortality from viral infectious diseases. In this regard, they may have considerable positive impact as a modality for improving global health. In this article, we introduce the possible role and summarize the current literature regarding TDDS applications for fighting common cutaneous or systemic viral infectious diseases, including herpes simplex, varicella or herpes zoster, warts, influenza, measles, and COVID-19.

Modeling drug transport within the viable skin - a review

INTRODUCTION

In the past, mathematical modeling of the transport of transdermal drugs has been primarily focused on the stratum corneum. However, the development of pharmaceutical technologies, such as chemical enhancers, iontophoresis, and microneedles, has led to two outcomes; an increase in permeability in the stratum corneum or the ability to negate the layer entirely. As a result, these outcomes have made the transport of a solute in the viable skin far more critical when studying transdermal drug delivery.

AREAS COVERED

The review will explicitly show the various attempts to model drug transport within the viable skin. Furthermore, a brief review will be conducted on the different models that explain stratum corneum transport, microneedle dynamics and estimation of the diffusion coefficient.

EXPERT OPINION

Future development of mathematical models requires the focus to be changed from traditional diffusion-based tissue models to more sophisticated three-dimensional models that incorporate the physiology of the skin.

Changes in Percutaneous Absorption of Fentanyl Patches in Rats Treated with a Sebum-Like Secretion

The percutaneous absorption of a fentanyl (FEN)-patch is affected by various external factors including the volume of sebum secretion, which causes changes in the skin surface environment. In this study, we prepared a lard-based sebum-like secretion (SLS), and applied it to investigate the effect of different skin surface conditions on the drug penetration of a FEN-patch. In vitro work to test drug release using the Franz diffusion cell indicated that drug release was significantly suppressed by treatment with 5% SLS, which is equivalent to the amount of daily human sebum secretion. Conversely, in ex vivo experiments using rat skin, the amount of FEN that accumulated in the skin tissue of the 5% SLS-treated rats was higher in comparison with the non-SLS treated group. Furthermore, in vivo experiments indicated that the plasma FEN concentration in rats treated with the FEN-patch was significantly increased by treatment with 5% SLS. These results suggest that the sebum affected the release, accumulation, and absorption of FEN from the FEN-patch, and the FEN concentration in the blood was reflected by the balance of the suppression of drug release and the enhancement of drug accumulation in the skin with SLS.

Does transdermal fentanyl work in patients with low BMI? Patient-reported outcomes of pain and percent pain relief in cancer patients on transdermal fentanyl

BACKGROUND

Low body mass index (BMI) is suspected of being associated with low transdermal fentanyl (TDF) blood levels and worse pain relief. Clinical pain data to support this claim are lacking.

METHODS

Using a Chronic Pain Registry, we identified 901 cancer patients who received TDF at outpatient pain service clinics of our cancer center from 7/1/2011 to 12/1/2016. Of these, 240 patients had a BMI measure, pain intensity, and pain relief scores documented within 30 days of a TDF order. We examined associations between BMI, TDF dose, Worst and Least pain scores, and pain relief scores using standard statistical tests.

RESULTS

In cancer patients receiving TDF, low BMI (<18.5) was significantly associated with greater pain relief irrespective of TDF dose and borderline significantly associated with greater percent pain relief after controlling for age, cancer diagnoses, and pain etiology (P = .073), suggesting that low BMI may independently predict better pain relief in cancer patients. As there were no significant associations between BMI and TDF dose, we find no basis for BMI-dependent dose modification or avoiding TDF in cachectic and low BMI patients.

CONCLUSIONS

When predicting percent pain relief, we conclude that there is no basis for avoiding TDF or modifying its dose in cancer patients with low BMI and cachexia.

Testosterone deficiency in non-cancer opioid-treated patients

PURPOSE

The use of opioids in patients with chronic non-cancer pain is common and can be associated with opioid-induced androgen deficiency (OPIAD) in men. This review aims to evaluate the current literature regarding the prevalence, clinical consequence and management of OPIAD.

METHODS

A database search was performed in Medline, Embase and Cochrane using terms such as "analgesics", "opioids" and "testosterone". Relevant literature from January 1969 to March 2018 was evaluated.

RESULTS

The prevalence of patients with OPIAD ranges from 19 to 86%, depending on the criteria for diagnosis of hypogonadism. The opioid-induced suppression of gonadotropin-releasing and luteinizing hormones represents the main important pathogenetic mechanisms. OPIAD has significant negative clinical consequences on sexual function, mood, bone density and body composition. In addition, OPIAD can also impair pain control leading to hyperalgesia, which can contribute to sexual dysfunction and mood impairment.

CONCLUSIONS

OPIAD is a common adverse effect of opioid treatment and contributes to sexual dysfunction, impairs pain relief and reduces overall quality of life. The evaluation of serum testosterone levels should be considered in male chronic opioid users and the decision to initiate testosterone treatment should be based on the clinical profile of individuals, in consultation with the patient.

Transdermal fentanyl as an adjuvant to paravertebral block for pain control after breast cancer surgery: A randomized, double-blind controlled trial

Objective:

The aim of this study is to investigate the effect of transdermal fentanyl (TDF) as an adjuvant to paravertebral block (PVB) for pain control after breast cancer surgery.

Patients and Methods:

This randomized, double-blind trial included fifty females with breast cancer scheduled for surgery. They were randomly allocated into one of two equal groups. The TDF group used transdermal fentanyl patches (TFPs) 25 μg/h applied 10 h preoperative then PVB with 20 mL of bupivacaine 0.25% was done before induction of general anesthesia. The PVB group used placebo patches in addition to PVB the same way as TDF group. Postoperative pain was assessed with a visual analog scale (VAS) score up to 48 h. Intravenous morphine 0.1 mg/kg was given when the VAS is ≥ 3 or on patient request. The primary outcome measures were the time to first request for analgesia and the total analgesic consumption in the first 48 h.

Results:

Relative to the VAS score reading was 30 min. After the end of surgery, VAS score decreased significantly in the two groups up to 48 postoperative hours and was significantly lower in TDF group up to 24 h. The time to first request of additional analgesia was significantly longer, and total dose of morphine consumption was significantly lower in TDF group (P < 0.001, and P = 0.039, respectively).

Conclusion:

TFPs releasing 25 μg/h is a safe and effective adjuvant to PVB after breast cancer surgery. It provides adequate analgesia with reduction of opioid consumption and minimal adverse effects.

Sumatriptan iontophoretic transdermal system for acute treatment of episodic migraine

Migraine is a common and debilitating condition affecting approximately nearly one in four women in the USA and Europe. Episodic attacks can be associated with a number of symptoms, with nausea and/or vomiting being among the most frequent and distressing. Sumatriptan is widely used for acute treatment of migraine and is available in several formulations. The efficacy of oral sumatriptan is well-established. However, patients who experience migraine-associated nausea and/or vomiting can have difficulty swallowing tablets and may delay taking anti-migraine medication. In addition, absorption of oral sumatriptan can be reduced by migraine-associated gastroparesis. Non-oral formulations of sumatriptan are recommended for patients with nausea and/or vomiting, but their use may be limited by adverse effects and patient acceptance. A new transdermal formulation of sumatriptan has recently become available in the USA for acute treatment of migraine in adults. In this article, we review the properties of the sumatriptan iontophoretic transdermal patch and discuss the evidence to support its use in clinical practice.

Fentanyl sublingual spray for breakthrough cancer pain in patients receiving transdermal fentanyl

AIM

To investigate the relationship between effective fentanyl sublingual spray (FSS) doses for breakthrough cancer pain (BTCP) and around-the-clock (ATC) transdermal fentanyl patch (TFP).

METHODS

Adults tolerating ATC opioids received open-label FSS for 26 days, followed by a 26-day double-blind phase for patients achieving an effective dose (100-1600 µg).

RESULTS

Out of 50 patients on ATC TFP at baseline, 32 (64%) achieved an effective dose. FSS effective dose moderately correlated with mean TFP dose (r = 0.4; p = 0.03). Patient satisfaction increased during the study. Common adverse event included nausea (9%) and peripheral edema (9%).

CONCLUSION

FSS can be safely titrated to an effective dose for BTCP in patients receiving ATC TFP as chronic cancer pain medication. ClinicalTrials.gov identifier: NCT00538850.

Crystallographic textures and morphologies of solution cast Ibuprofen composite films at solid surfaces

The preparation of thin composite layers has promising advantages in a variety of applications like transdermal, buccal, or sublingual patches. Within this model study the impact of the matrix material on the film forming properties of ibuprofen–matrix composite films is investigated. As matrix materials polystyrene, methyl cellulose, or hydroxyl-ethyl cellulose were used. The film properties were either varied by the preparation route, i.e., spin coating or drop casting, or via changes in the relative ratio of the ibuprofen and the matrix material. The resulting films were investigated via X-ray diffraction and atomic force microscope experiments. The results show that preferred (100) textures can be induced via spin coating with respect to the glass surface, while the drop casting results in a powder-like behavior. The morphologies of the films are strongly impacted by the ibuprofen amount rather than the preparation method. A comparison of the various matrix materials in terms of their impact on the dissolution properties show a two times faster zero order release from methyl cellulose matrix compared to a polystyrene matrix. The slowest rate was observed within the hydroxyl ethyl cellulose as the active pharmaceutical ingredients (APIs) release is limited by diffusion through a swollen matrix. The investigation reveals that the ibuprofen crystallization and film formation is only little effected by the selected matrix material than that compared to the dissolution. A similar experimental approach using other matrix materials may therefore allow to find an optimized composite layer useful for a defined application.

Dosing considerations with transdermal formulations of fentanyl and buprenorphine for the treatment of cancer pain

Opioids continue to be first-line pharmacotherapy for patients suffering from cancer pain. Unfortunately, subtherapeutic dosage prescribing of pain medications remains common, and many cancer patients continue to suffer and experience diminished quality of life. A large variety of therapeutic options are available for cancer pain patients. Analgesic pharmacotherapy is based on the patient’s self-report of pain intensity and should be tailored to meet the requirements of each individual. Most, if not all, cancer pain patients will ultimately require modifications in their opioid pharmacotherapy. When changes in a patient’s medication regimen are needed, adequate pain control is best maintained through appropriate dosage conversion, scheduling immediate release medication for withdrawal prevention, and providing as needed dosing for breakthrough pain. Transdermal opioids are noninvasive, cause less constipation and sedation when compared to oral opioids, and may improve patient compliance. A relative potency of 100:1 is recommended when converting the patient from oral morphine to transdermal fentanyl. Based on the limited data available, there is significant interpatient variability with transdermal buprenorphine and equipotency recommendations from oral morphine of 75:1–110:1 have been suggested. Cancer patients may require larger transdermal buprenorphine doses to control their pain and may respond better to a more aggressive 75–100:1 potency ratio. This review outlines the prescribing of transdermal fentanyl and transdermal buprenorphine including how to safely and effectively convert to and use them for those with cancer pain.

Transdermal fentanyl patch for postoperative analgesia in total knee arthroplasty: a randomized double-blind controlled trial

PURPOSE

To assess the efficacy of a transdermal fentanyl patch (TFP) (50 μg/hour) applied 10-12 hours before surgery versus placebo for postoperative pain control of total knee arthroplasty (TKA).

MATERIALS AND METHODS

We enrolled 40 patients undergoing elective TKA under spinal anesthesia using isobaric or hyperbaric bupivacaine. Subjects were randomized to receive a TFP (Duragesic(®) 50 μg/hour) or placebo patch applied with a self-adhesive to the anterior chest wall 10-12 hours before spinal anesthesia. Every patient was given patient-controlled morphine for postoperative pain control. Patients were evaluated every 4 hours until 48 hours.

RESULTS

Morphine consumption at 24 and 48 hours in the TFP group versus the placebo group was 15.40±12.65 and 24.90±20.11 mg versus 33.60±19.06 and 57.80±12.65 mg (P≤0.001). Numeric rating scale scores at rest and during movement over 48 hours were lower in the TFP group. Ambulation and nausea/vomiting scores were statistically greater, but not clinically significant in the TFP group. Sedation scores were low and not statistically significantly different between groups. There was no severe respiratory depression.

CONCLUSION

TFP (50 μg/hour) applied 10-12 hours before surgery can effectively and safely decrease morphine consumption and pain scores during the first 48 hours after TKA surgery.

An examination of the postmortem redistribution of fentanyl and interlaboratory variability

Fentanyl is a synthetic opioid agonist used for pain control. Often administered as a transdermal patch, it is an interesting drug for study of postmortem redistribution. We hypothesized that fentanyl concentrations would increase over time after death, as measured in blood drawn on the day prior to autopsy and in blood drawn at the time of autopsy in ten cases where fentanyl patches were identified at the scene. Concentrations were compared, and heart blood to femoral blood ratios were calculated as markers of postmortem redistribution. Fentanyl concentrations measured in peripheral blood drawn the day of autopsy (peripheral blood 2 [PB2]) were higher than those drawn the day prior to autopsy (peripheral blood 1 [PB1]) with a mean ratio (PB2/PB1) of 1.80. The ratio of heart blood concentrations (HB) to femoral blood concentrations drawn at autopsy (PB2) had a mean ratio (HB/PB2) of 1.08. Some cases had blood from the same source analyzed at two different laboratories, and concentrations of fentanyl in those samples showed inter- and intralaboratory differences up to 25 ng/mL. Postmortem fentanyl concentrations may be affected by antemortem factors, postmortem redistribution, and laboratory variability. Forensic pathologists must use caution in interpreting fentanyl levels as part of death investigation.

Alternative routes to oral opioid administration in palliative care: a review and clinical summary

OBJECTIVE

A major goal of palliative care is to provide comfort, and pain is one of the most common causes of treatable suffering in patients with advanced disease. Opioids are indispensable for pain management in palliative care and can usually be provided by the oral route, which is safe, effective, and of lowest cost in most cases. As patients near the end of life, however, the need for alternate routes of medication increases with up to 70% of patients requiring a nonoral route for opioid administration. In order to optimize patient care, it is imperative that clinicians understand existing available options of opioid administration and their respective advantages and disadvantages.

METHODS

We performed a literature review to describe the most commonly used and available routes that can substitute for oral opioid therapy and to provide a summary of factors affecting choice of opioid for use in palliative care in terms of benefits, indications, cautions, and general considerations.

RESULTS

Clinical circumstances will largely dictate appropriateness of the route selected. When the oral route is unavailable, subcutaneous, intravenous, and enteral routes are preferred in the palliative care population. The evidence supporting sublingual, buccal, rectal, and transdermal gel routes is mixed.

CONCLUSIONS

This review is not designed to be a critical appraisal of the quality of current evidence; rather, it is a summation of that evidence and of current clinical practices regarding alternate routes of opioid administration. In doing so, the overarching goal of this review is to support more informed clinical decision making.

Medication errors related to transdermal opioid patches: lessons from a regional incident reporting system

OBJECTIVE

A few cases of adverse reactions linked to erroneous use of transdermal opioid patches have been reported in the literature. The aim of this study was to describe and characterize medication errors (MEs) associated with use of transdermal fentanyl and buprenorphine.

METHODS

All events concerning transdermal opioid patches reported between 2004 and 2011 to a regional incident reporting system and assessed as MEs were scrutinized and characterized. MEs were defined as "a failure in the treatment process that leads to, or has the potential to lead to, harm to the patient".

RESULTS

In the study 151 MEs were identified. The three most common error types were wrong administration time 67 (44%), wrong dose 34 (23%), and omission of dose 20 (13%). Of all MEs, 118 (78%) occurred in the administration stage of the medication process. Harm was reported in 26 (17%) of the included cases, of which 2 (1%) were regarded as serious harm (nausea/vomiting and respiratory depression). Pain was the most common adverse reaction reported.

CONCLUSIONS

Of the reported MEs related to transdermal fentanyl and buprenorphine, most occurred during administration. Improved routines to ascertain correct and timely administration and educational interventions to reduce MEs for these drugs are warranted.

Pitfalls of intranasal naloxone

We present a case of failed prehospital treatment of fentanyl induced apnea with intranasal (IN) naloxone. While IN administration of naloxone is becoming more common in both lay and pre-hospital settings, older EMS protocols utilized intravenous (IV) administration. Longer-acting, higher potency opioids, such as fentanyl, may not be as easily reversed as heroin, and studies evaluating IN administration in this population are lacking. In order to contribute to our understanding of the strengths and limitations of IN administration of naloxone, we present a case where it failed to restore ventilation. We also describe peer reviewed literature that supports the use of IV naloxone following heroin overdose and explore possible limitations of generalizing this literature to opioids other than heroin and to IN routes of administration.

Caring for patients with chronic pain: pearls and pitfalls

Chronic, nonmalignant pain is a substantial public health problem in the United States. Research over the past 2 decades has defined chronic pain by using a "biopsychosocial model" that considers a patient's biology and psychological makeup in the context of his or her social and cultural milieu. Whereas this model addresses the pathology of chronic pain, it also places many demands on the physician, who is expected to assess and manage chronic pain safely and successfully. There is a growing body of evidence suggesting that opioids can be effective in the management of chronic pain, but there has also been a rise in opioid-related overdoses and deaths. Clinicians should be aware of assessment tools that may be used to evaluate the risk of opioid abuse. A basic understanding of chronic pain pathophysiology and a uniform approach to patient care can satisfy the needs of both patients and physicians.

Transdermal fentanyl for cancer pain

BACKGROUND

Opioid drugs have been used for many years to relieve pain. Transdermal fentanyl offers one option for delivering and maintaining pain relief in patients with moderate or severe cancer pain.

OBJECTIVES

To determine the analgesic efficacy of transdermal fentanyl for relief of cancer pain, and to assess the adverse events associated with the use of transdermal fentanyl for relief of cancer pain.

SEARCH METHODS

The following databases were searched: Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 4 of 12); MEDLINE (1966 to May 2013); EMBASE (1974 to May 2013; CANCERLIT (PubMED) (November 2012); and ClinicalTrials.gov (May 2013).

SELECTION CRITERIA

Published randomised controlled trials (RCTs) using placebo or active comparators reporting on the analgesic effect of transdermal fentanyl in adults and children with cancer pain. Studies with fewer than 10 participants were excluded.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two review authors. We extracted any available data on the number or proportion of patients with 'no worse than mild pain' or treatment success (very satisfied, or very good or excellent on patient global impression scales), together with information about adverse events and withdrawals.

MAIN RESULTS

We identified nine studies meeting the inclusion criteria, including a Turkish study that is awaiting formal translation. There were 1244 participants randomised in classically designed RCTs, of whom 1197 had evaluable data, and 138 patients enrolled in an enriched enrolment, randomised withdrawal (EERW) trial. Overall, 600 participants were treated with transdermal fentanyl patches, 382 with various formulations of morphine, 36 with methadone, and 221 with paracetamol plus codeine. There were major sources of potential bias, including lack of blinding, small size, high levels of attrition, and inconsistent reporting.We could not compare data in a meaningful analysis regarding adverse events such as nausea, abdominal pain, gastrointestinal bleeding, and confusion. These events may have been attributable to the underlying disease process.There were insufficient comparable data for meta-analysis to be undertaken or to produce numbers needed to treat (NNT) for the analgesic effect. In seven studies with 461 participants reporting pain intensity results after about two weeks, the mean or median pain scores were on the borderline of mild and moderate pain. Most participants would have had no worse than mild pain on treatment. Another reported that 77% of participants using transdermal fentanyl had an undefined successful outcome. Fewer participants experienced constipation with transdermal fentanyl (28%) than with oral morphine (46%), giving a risk ratio of 0.61 (95% CI 0.47 to 0.78); the NNT to prevent constipation was 5.5 (95% CI 3.8 to 10).

AUTHORS' CONCLUSIONS

The randomised trial literature for effectiveness of transdermal fentanyl is limited, but it is an important medicine. Most studies recruited fewer than 100 participants and did not provide data appropriate for meta-analysis. Only a few reported how many patients had good pain relief but, where data were reported, a majority had no worse than mild pain within a reasonably short time period. The evidence pointed to a useful and significant reduction in complaints about constipation for transdermal fentanyl compared with oral morphine.

Update on prescription extended-release opioids and appropriate patient selection

Chronic pain is largely underdiagnosed, often undertreated, and expected to increase as the American population ages. Many patients with chronic pain require long-term treatment with analgesic medications, and pain management may involve use of prescription opioids for patients whose pain is inadequately controlled through other therapies. Yet because of the potential for abuse and addiction, many clinicians hesitate to treat their patients with pain with potentially beneficial agents. Finding the right opioid for the right patient is the first - often complicated - step. Ensuring that patients continue to properly use the medication while achieving therapeutic analgesic effects is the long-term goal. Combined with careful patient selection and ongoing monitoring, new formulations using extended-release technologies incorporating tamper-resistant features may help combat the growing risk of abuse or misuse, which will hopefully reduce individual suffering and the societal burden of chronic pain. The objective of this manuscript is to provide an update on extended-release opioids and to provide clinicians with a greater understanding of which patients might benefit from these new opioid formulations and how to integrate the recommended monitoring for abuse potential into clinical practice.

Chronological age affects the permeation of fentanyl through human skin in vitro

AIM

To study the influence of chronological age on fentanyl permeation through human skin in vitro using static diffusion cells. Elderly individuals are known to be more sensitive to opioids and obtain higher plasma concentrations following dermal application of fentanyl compared to younger individuals. The influence of age - as an isolated pharmacokinetic term - on the absorption of fentanyl has not been previously studied.

METHOD

Human skin from 30 female donors was mounted in static diffusion cells, and samples were collected during 48 h. Donors were divided into three age groups: <30 years of age (n = 6), ≥30 and <60 years of age (n = 18) and ≥60 years of age (n = 6).

RESULTS

The youngest group had a significantly higher mean absorption (3,100 ng/cm(2)) than the two other groups (2,000 and 1,475 ng/cm(2), respectively) and a significant larger AUC (young age group: 9,393 ng; middle and old age groups: 5,922 and 4,050 ng, respectively). Furthermore, the lag time and absorption rate were different between the three groups, with a significantly higher rate in the young participants versus the oldest participants.

CONCLUSION

We demonstrate that fentanyl permeates the skin of young individuals in greater amounts and at a higher absorption rate than in middle-aged and old individuals in vitro.

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.

Is morphine still the best reference opioid?

SUMMARY Cancer and noncancer pain can usually be managed according to the WHO analgesic ladder and, in many countries, morphine remains the first-line opioid of choice for chronic severe pain. There have been many advances in the use of opioids for moderate-to-severe pain control in recent years. Consequently, the position of morphine as the gold standard became gradually more questioned, mostly because of serious adverse effects and the availability of different opioids and new formulations. The place of morphine as the first-line option is based on reasons of familiarity, availability or cost rather than medical advantages. In recent years, a number of systematic reviews failed to demonstrate superiority of morphine over other opioids in terms of efficacy or tolerability. Moreover, some strong opioids have shown improved tolerability or convenience. Currently, morphine might still be considered as a reference drug for equivalent dosing, but not for strategic healthcare decisions, as it has not demonstrated clinical or pharmacological superiority over other opioids. Therefore, there is a lack of evidence to sustain the role of morphine as the gold standard in the treatment of chronic severe pain.

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.

Effect of transdermal fentanyl patches on the motility of the sphincter of oddi

BACKGROUND/AIMS

Pain is one of the most troublesome symptoms of pancreatitis. Transdermal fentanyl patches (TFPs) are long-acting analgesics with a reduced risk of dependency. This prospective study evaluated the effect of TFPs on sphincter of Oddi (SO) motility for the management of pain in pancreatitis.

METHODS

SO manometry (SOM) was performed using triple-lumen catheters anterogradely inserted through the percutaneous transhepatic route during cholangioscopy in 16 patients. The basal pressure, amplitude, and frequency of the SO were assessed before and after applying a TFP at 24 hour at doses of 25 and 12.5µg/hr, respectively.

RESULTS

Two of 16 patients receiving a 25µg/hr. TFP were excluded because of adverse side effects (headache and/or nausea). The mean basal pressure, amplitude, and frequency of SOM did not change significantly in the 25µg/hr TFP group (n=4 patients). Parameters of SO function also did not significantly change in the 12.5µg/hr TFP group (n=11 patients).

CONCLUSIONS

TFPs below a dose of 25µg/hr may not affect the motility of the SO. Administration of TFPs at lower dosages seems to be a safe analgesic treatment for the pain control of patients with pancreatitis without affecting the function of the SO.

High compliance with rotigotine transdermal patch in the treatment of idiopathic Parkinson's disease

PURPOSE

The non-ergot dopamine agonist rotigotine has been formulated in a once-daily transdermal patch for 24-h application which ensures continuous rotigotine release over 24 h. This open, prospective, non-interventional study investigated compliance with the patch under clinical practice conditions.

METHODS

Data were collected by German practice-based neurologists, prescribing rotigotine to patients with idiopathic Parkinson's disease; the observation period was 4 months. Following titration, 943 patients (mean age 67.6 +/- 9.3 years; 59% male) were maintained on rotigotine for at least 4 weeks (per-protocol population). At the end of the observation period, this patient population was assessed for various aspects of compliance using a 4-item Morisky scale ranging from 1 = least compliance to 4 = maximal compliance. Safety was evaluated in all 1099 patients receiving rotigotine treatment.

RESULTS

The mean satisfactory rotigotine dose of 5.4 +/- 1.6 mg/24 h was reached after 27 +/- 17 days; 84% of the patients did not require dose adjustments during maintenance. Complete compliance questionnaires were available for 863 patients (92%) who achieved a mean compliance sum score of 15.1 +/- 1.6 points out of the maximum 16 points. Mean scores of 3.6-3.9 points for the four scale items indicate that the patch was applied once-daily and at the appropriate time by the majority of the patients, independent of their clinical status. Skin reactions (3.7%) and known dopaminergic side-effects such as nausea (3.5%) were mostly mild or moderate in intensity.

CONCLUSIONS

Rotigotine transdermal patch was associated with high compliance in patients with Parkinson's disease under clinical practice conditions.

MMPI disability profile is associated with degree of opioid use in chronic work-related musculoskeletal disorders

OBJECTIVE

To examine the relationship between level of opioid use and Minnesota Multiphasic Personality Inventory (MMPI) findings among chronic pain patients who were about to begin a functional restoration program.

METHODS

A prospective cohort study of patients with chronic disabling occupational musculoskeletal disorders. A total of 768 consecutive patients with valid MMPI were divided into 2 groups: 398 patients who reported no opioid use upon admission (No); and 370 patients who reported opioid use upon admission (Yes). Average daily opioid doses (in morphine equivalents) could be determined for 287 of 370 patients, who were further divided into 4 opioid subgroups: Low (>0 to 30 mg, n=148); Medium (>30 to 60 mg, n=57); High (>60 to 120 mg, n=47); and Very High (>120 mg, n=35).

RESULTS

Seventy-five percent of the patients who produced valid MMPI profiles could be classified into 1 of the 4 MMPI profiles. Of those patients who could be classified, approximately 7% showed a Normal profile, 15% showed a Conversion V, 9% showed a Neurotic Triad, and 69% showed the Disability Profile. Although the Disability Profile accounted for the majority of patients in all opioid subgroups, the proportions did increase with pretreatment opioid dose, as expected, indicating a relationship between degree of psychopathology and level of pretreatment opioid use. Patients who did not take pretreatment opioids showed the highest proportions of Conversion V and Normal profiles, which indicate a lesser degree or absence of psychopathology, respectively. Patients who took pretreatment opioids were more than one-and-a-half times as likely as patients who did not take pretreatment opioids to produce the Disability Profile, whereas patients taking very high doses of pretreatment opioids were nearly 3 times as likely to produce this profile as patients who took no pretreatment opioids.

CONCLUSIONS

The results of this study support the hypothesis that increasing levels of pretreatment opioid use is associated with less desirable MMPI profiles, specifically the Disability Profile and, thus, greater levels of pretreatment psychopathology.