Dose proportionality and pharmacokinetics of oral transmucosal fentanyl citrate

Breakthrough pain and rapid-onset opioids in patients with cancer pain: a narrative review

Breakthrough pain is transitory pain that occurs despite the use of opioids for background pain control. Breakthrough pain occurs in 40% to 80% of patients with cancer pain. Despite effective analgesic therapy, patients and their caregivers often feel that their pain is not sufficiently controlled. Therefore, an improved understanding of breakthrough pain and its management is essential for all physicians caring for patients with cancer. This article reviews the definition, clinical manifestations, accurate diagnostic strategies, and optimal treatment options for breakthrough pain in patients with cancer. This review focuses on the efficacy and safety of rapid-onset opioids, which are the primary rescue drugs for breakthrough pain.

Evaluating the Pharmacokinetics of Fentanyl in the Brain Extracellular Fluid, Saliva, Urine, and Plasma of Newborns from Transplacental Exposure from Parturient Mothers Dosed with Epidural Fentanyl Utilizing PBPK Modeling

BACKGROUND AND OBJECTIVE

Fentanyl can mitigate the mother and newborn complications resulting from labor pain. However, fentanyl shows a narrow therapeutic index between its respiratory depressive and analgesic effects. Thus, prenatally acquired high fentanyl levels in the newborn brain extracellular fluid (bECF) may induce respiratory depression which requires therapeutic drug monitoring (TDM). TDM using saliva and urine in newborns can reduce the possibility of infections and distress associated with TDM using blood. The objective of this study was to develop  a physiologically based pharmacokinetic (PBPK) model to predict fentanyl concentrations in different newborn tissues due to intrauterine exposure.

METHODS

A fentanyl PBPK model in adults after intravenous and epidural administration was built, validated, and scaled to pregnancy and newborn populations. The dose that the newborn received transplacentally at birth was calculated using the pregnancy model. Then, the newborn bECF, saliva, plasma, and urine concentrations after such a dose were predicted using the newborn PBPK model.

RESULTS

After a maternal epidural dose of fentanyl 245 µg, the predicted newborn plasma and bECF levels were below the toxicity thresholds. Furthermore, the salivary threshold levels in newborns for fentanyl analgesic and respiratory depression effects were estimated to be 0.39 and 14.7-18.2 ng/ml, respectively.

CONCLUSION

The salivary TDM of fentanyl in newborns can be useful in newborns exposed to intrauterine exposure from parturient females dosed with epidural fentanyl. However, newborn-specific values of µ-opioid receptors IC50 for respiratory depression are needed.

Pharmacokinetic Characterisation and Comparison of Bioavailability of Intranasal Fentanyl, Transmucosal, and Intravenous Administration through a Three-Way Crossover Study in 24 Healthy Volunteers

Background

For more than 60 years, the synthetic opioid fentanyl has been widely used in anaesthesia and analgesia. While the intravenous formulation is primarily used for general anaesthesia and intensive care settings, the drug's high lipophilic properties also allow various noninvasive routes of administration. Published data suggest that intranasal administration is also attractive for use as intranasal patient-controlled analgesia (PCA). A newly developed intranasal fentanyl formulation containing 47 μg fentanyl, intravenous fentanyl, and oral transmucosal fentanyl citrate were characterised, and bioavailability was compared to assess the suitability of the intranasal formulation for an intranasal PCA product.

Methods

27 healthy volunteers were enrolled in a single-centre, open-label, randomised (order of treatments), single-dose study in a three-period crossover design. The pharmacokinetics of one intranasal puff of fentanyl formulation (47 μg, 140 mL per puff), one short intravenous infusion of 50 μg fentanyl, and one lozenge with an integrated applicator (200 μg fentanyl) were studied, and bioavailability was calculated. Blood samples were collected over 12 hours, and plasma concentrations of fentanyl were determined by HPLC with MS/MS detection.

Results

24 volunteers completed the study. The geometric mean of AUC_0-tlast was the highest with oral transmucosal administration (1106 h ∗ pg/ml, CV% = 32.86), followed by intravenous (672 h ∗ pg/ml, CV% = 32.18) and intranasal administration (515 h ∗ pg/ml, CV% = 30.10). C _max was 886 pg/ml (CV% = 59.38) for intravenous, 338 pg/ml (CV% = 45.61) for intranasal, and 310 pg/ml (CV% = 29.58) for oral transmucosal administration. t _max was shortest for intravenous administration (0.06 h, SD = 0.056), followed by intranasal (0.21 h, SD = 0.078) and oral transmucosal administration (1.20 h, SD = 0.763). Dose-adjusted absolute bioavailability was determined to be 74.70% for the intranasal formulation and 41.25% for the oral transmucosal product. In total, 38 adverse events (AEs) occurred. Fourteen AEs were potentially related to the investigational items. No serious AE occurred.

Conclusion

Pharmacokinetic parameters and bioavailability of the investigated intranasal fentanyl indicated suitability for its intended use as an intranasal PCA option.

Opioids in cancer-related pain: current situation and outlook

PURPOSE

Despite progress in treatments, cancer pain remains underestimated, poorly assessed and under-treated. Prescribing strong opioids, because of their specificities, requires precision in management considering their pharmacology but also a clear understanding of recommendations. Some clinicians highlight the risk of addiction, excessive sedation and respiratory depression and their need for information. Our objective in this review is to suggest some clinical guidance for the positioning and daily use of opioids within cancer pain management.

METHODS

Critical reflection based on literature analysis and clinical practice.

RESULTS

Strong opioids may be initiated as soon as pain diagnosis is defined. Factors to consider are pain aetiology, opioid pharmacokinetics and pharmacodynamics, genetic polymorphism, physiology (age, gender, weight and pregnancy), comorbidities (especially renal, hepatic, cardiovascular diseases), chronobiology, environmental factors, medication interference and treatment adherence. Achieving the best-balanced opioid treatment for background pain is complex, mainly due to the variable benefit/risk ratio between individuals and the experience of breakthrough cancer pain. Opioid initiation alongside a dynamic reassessment of pain should be fully integrated into the patient's management to optimise analgesia. The efficacy and safety of a strong opioid treatment need to be re-evaluated and adapted to individuals constantly as it varies over time.

CONCLUSIONS

Cancer pain is multimorphic and permanently changing due to disease evolution, curative treatments and disruptive events (concomitant treatments, pain from associated disease, comorbidities and complications, modifications of the environment). Well-managed opioids are the cornerstone of a complex environment requiring multidisciplinary dynamic assessments integrated into the patient's care pathway.

Rapid acting fentanyl formulations in breakthrough pain in cancer. Drug selection by means of the System of Objectified Judgement Analysis

Drug selection of rapid acting fentanyl formulations in the treatment of breakthrough pain in patients with cancer is performed by the System of Objectified Judgement Analysis method. All seven available formulations were included in the analysis. The following selection criteria were used: number of available strengths, variability in the rate of absorption, interactions, clinical efficacy, side effects, ease of administration and documentation. No direct double-blind comparative studies between two or more formulations were identified and the clinical documentation of all formulations is limited. The most distinguishing criterion was ease of use. This led to slightly higher scores for Abstral, Instanyl and PecFent than for the other formulations. The pros and cons of each formulation should be discussed with the patient, and the most suitable formulation selected for each individual patient.

Management of the acute painful crisis in sickle cell disease- a re-evaluation of the use of opioids in adult patients

Management of the acute painful crisis (APC) of sickle cell disease (SCD) remains unsatisfactory despite advances in the understanding and management of acute pain in other clinical settings. One reason for this is an unsophisticated approach to the use of opioid analgesics for pain management. This applies to haematologists who are responsible for developing acute sickle pain management protocols for their patients, and to health care staff in the acute care setting. The objective of this article is to evaluate the evidence for use of opioids in APC management. We have highlighted the possibilities for improving management by using alternatives to morphine, and intranasal (IN) or transmucosal routes of administration for rapid onset of analgesia in the emergency department (ED). We suggest how experience gained in managing acute sickle pain in children could be extrapolated to adolescents and young adults. We have also questioned whether patients given strong opioids in the acute setting are being safely monitored and what resources are required to ensure efficacy, safety and patient satisfaction. We also identify aspects of care where there are significant differences of opinion, which require further study by randomized controlled trial.

Faster absorption and higher systemic bioavailability of intranasal fentanyl spray compared to oral transmucosal fentanyl citrate in healthy subjects

CONTEXT

Intranasal fentanyl spray (INFS) was developed for the treatment of breakthrough pain in cancer patients using an alternative route of administration.

OBJECTIVE

The aim of this clinical study was to investigate the pharmacokinetic (PK) profile and bioavailability of INFS in healthy subjects compared to oral transmucosal fentanyl citrate (OTFC).

MATERIALS AND METHODS

In a randomized, single-center, open-label, two-way crossover PK study, 24 subjects (12 male, 12 female, mean age 25.2 years) received INFS (single-dose delivery system 200 μg/100 μl) and OTFC (buccal lozenge, 200 µg). Naltrexone was given to prevent potential adverse reactions. Frequent plasma samples were taken up to 96 h and analyzed by LC-MS/MS with a lower limit of quantitation of 25 pg/ml. Primary PK parameter was the area under the fentanyl plasma concentration-time curve (AUC(0-inf)).

RESULTS

Compared to OTFC, a much faster absorption rate was observed for INFS which was supported by the much earlier appearance of detectable fentanyl plasma levels and a shorter T(max). At 15 min post-dose, the mean plasma fentanyl levels reached 602 pg/ml for INFS and 29 pg/ml for OTFC. Significantly higher C(max) and AUC values were obtained with INFS compared to OTFC. Although administered for 15 min, consumption of OTFC was incomplete in many incidences (∼70%) upon visual inspection. No safety concerns were identified for fentanyl administration in combination with oral naltrexone.

DISCUSSION AND CONCLUSION

One dose of INFS gives significantly higher plasma fentanyl levels and significantly higher bioavailability than OTFC based on dose-normalized AUC.

Considerations in selecting rapid-onset opioids for the management of breakthrough pain

Breakthrough pain (BTP) is a transitory pain that occurs despite the use of long-term, around-the-clock analgesia. It is highly prevalent in certain populations and places a significant burden on patients, their families, caregivers, and health-care systems. Despite its prevalence and impact, BTP is sometimes unrecognized and often undertreated. Various formulations of fentanyl – a rapid-onset opioid with short duration of action – are available for the management of BTP. The efficacy of formulations using transmucosal, transbuccal, sublingual, and intranasal administration routes has been demonstrated for BTP treatment in clinical trials. However, a lack of head-to-head trials evaluating their relative efficacy makes it challenging for physicians to reach informed decisions on the most efficacious intervention for individual patients. In the absence of clear data on the relative efficacy of fentanyl formulations, prescribing decisions need to be based on physician understanding and experience and product cost and availability, taking into account the individual patient’s needs, the ability of the patient or caregivers to administer medication, and the patient’s wishes. This review evaluates current pharmacologic methods of alleviating BTP and discusses factors that should be considered when selecting the most appropriate formulation for individual patients. With the range of fentanyl formulations available, it is now possible to successfully address BTP in the majority of patients.

A review of the pharmacokinetic profile of transmucosal fentanyl formulations

BACKGROUND AND OBJECTIVES

Breakthrough pain (BTP) is a transitory flare of moderate-to-severe pain that occurs in patients with stable, controlled persistent pain. Management of BTP episodes is difficult because frequency, time-to-peak intensity, and duration of episodes vary both within and between individuals. Formulations of fentanyl that use a buccal, sublingual, or nasal transmucosal route of administration have been developed for the treatment of BTP in opioid-tolerant patients with cancer. These formulations allow rapid passage into the bloodstream and avoid first-pass metabolism and, therefore, are more likely to match the time-course of BTP episodes than are oral formulations. The purposes of this analysis were to identify and review published data describing the pharmacokinetic properties of rapid-onset fentanyl formulations and to evaluate these properties in view of the temporal dynamic characteristics of BTP in order to help guide medical practice.

METHODS

Relevant publications were searched in the PubMed database from 1998. The plasma drug concentration-time profile of each formulation obtained from the identified studies was adjusted to a consistent scale for comparison.

RESULTS

The data revealed that the various transmucosal formulations resulted in three typical plasma fentanyl concentration profiles: (1) type 1: a very rapid rise and short duration; (2) type 2: a rapid increase and sustained intensity; and (3) type 3: a slower onset and longer duration.

CONCLUSIONS

Given the substantial variability of BTP episodes experienced by patients, these pharmacokinetic differences may provide useful information for a physician who is selecting a rapid-onset opioid medication for a patient.

A comprehensive review of rapid-onset opioids for breakthrough pain

Breakthrough pain (BTP) is a transitory pain (reaching maximum severity in ~15 minutes and lasting ~60 minutes in patients with cancer) that occurs despite the management of chronic pain with long-term around-the-clock analgesia. BTP occurs in 33-65% of patients with chronic cancer pain and in ~70% of patients with chronic noncancer pain. BTP has historically been managed with short-acting opioids; however, these medications have a pharmacokinetic profile that does not correlate with the sudden onset and short time to maximum severity of BTP. Interest in rapid-onset opioids to relieve BTP has therefore been growing. This comprehensive review aims to summarize the currently available clinical data for the approved rapid-onset opioids, which comprise different formulations of fentanyl, a μ-opioid receptor agonist with anaesthetic and analgesic properties. Administration routes for fentanyl in the management of BTP currently include the transmucosal and intranasal routes; an intrapulmonary formulation is also in development. The findings of this review suggest that the efficacy and safety of the approved rapid-onset opioids are comparable.

Oral trasmucosal fentanyl citrate for breakthrough pain treatment in cancer patients

INTRODUCTION

Breakthrough cancer pain has been defined as a transitory increase in pain intensity that occurs either spontaneously or in relation to a specific predictable or unpredictable trigger, despite relatively stable and adequately controlled background pain. The availability of supplemental doses of oral opioids, in addition to the continuous analgesic medication, is the main treatment suggested to manage pain flares.

AREAS COVERED

Oral transmucosal fentanyl citrate (OTFC) is the first product of a new generation of delivery systems, named rapid-onset opioids (ROOs), characterized by rapidity of effect and the short duration of analgesia. Controlled studies and long-term experience have shown that OTFC is an effective treatment for breakthrough pain management and its use should be considered in any patient experiencing breakthrough pain related to cancer.

EXPERT OPINION

The onset of action of OTFC - demonstrated to start within 15 min - and the short time to maximum concentration make it a useful indication for breakthrough pain; dose titration is commonly recommended. However, it is likely that patients receiving high doses of opioids for background analgesia will not be candidates for titration with minimal initial doses of OTFC, as they are opioid tolerant and the process would be time consuming.

Fentanyl for breakthrough pain: a systematic review

The purpose of this article is to systematically review the use of fentanyl as an analgesic for breakthrough pain. This article found that the oral transmucosal fentanyl (OTFC) had a quicker onset to analgesia than oral immediate-release opioids. Intranasal fentanyl (INFS) had a quicker onset to analgesia than buccal tablets, which in turn had a quicker onset to analgesia than OTFC. Patient acceptance and global rating of efficacy were greater for INFS than for buccal fentanyl. OTFC and INFS have been used effectively to reduce acute pain in children who are opioid-naive. Abuse and addiction to OTFC, fentanyl buccal tablets and INFS was low, owing to patient selection.

Pharmacokinetics, safety, and tolerability of ascending doses of sublingual fentanyl, with and without naltrexone, in Japanese subjects

This open-label, nonrandomized study assessed single and repeat ascending doses of a new sublingual fentanyl (SLF) formulation in 48 healthy Japanese opiate-naïve subjects (47 completed). Subjects received single-dose SLF 100, 200, 400, or 800 µg followed by 13 doses 6 hourly, at their dose level. Subjects taking repeat-dose 400 and 800 µg were pretreated with naltrexone in order to block opiate-receptor-mediated effects on respiration, monitored by pulse oximetry and transcutaneous pco(2). Sublingual fentanyl was rapidly and consistently absorbed. After single doses, median t(first) was 0.08 to 0.25 hours and t(max) 0.50 to 1.00 hours. After repeat dosing, median t(max) (t(max,ss)) was 0.50 to 2.00 hours. Plasma concentrations were dose proportional both after single and repeat dosing, and naltrexone appeared to have no effect on SLF pharmacokinetics. Plasma fentanyl reached steady state within the 72-hour dosing period and accumulation was approximately 2-fold. After single doses, effects on respiratory variables were evident after the 400-µg and 800-µg doses. Transcutaneous pco(2) was not helpful in detecting respiratory depression. Thus, SLF yielded rapid absorption of fentanyl and dose-proportional plasma concentrations that, for 400 µg and 800 µg, were within the typical analgesic range. Respiratory depression in these opioid-naïve volunteers was manageable with simple clinical measures.

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.

Recent advances in the use of opioids for cancer pain

Opioids are the mainstay of treatment for moderate to severe cancer pain. In recent years there have been many advances in the use of opioids for cancer pain. Availability and consumption of opioids have increased and opioids other than morphine (including methadone, fentanyl, oxycodone) have become more widely used. Inter-individual variation in response to opioids has been identified as a significant challenge in the management of cancer pain. Many studies have been published demonstrating the benefits of opioid switching as a clinical maneuver to improve tolerability. Constipation has been recognized as a significant burden in cancer patients on opioids. Peripherally restricted opioid antagonists have been developed for the prevention and management of opioid induced constipation. The phenomenon of breakthrough pain has been characterized and novel modes of opioid administration (transmucosal, intranasal, sublingual) have been explored to facilitate improved management of breakthrough cancer pain. Advances have also been made in the realm of molecular biology. Pharmacogenetic studies have explored associations between clinical response to opioids and genetic variation at a DNA level. To date these studies have been small but future research may facilitate prospective prediction of response to individual drugs.

Pediatric palliative care: use of opioids for the management of pain

Pediatric palliative care (PPC) is provided to children experiencing life-limiting diseases (LLD) or life-threatening diseases (LTD). Sixty to 90% of children with LLD/LTD undergoing PPC receive opioids at the end of life. Analgesia is often insufficient. Reasons include a lack of knowledge concerning opioid prescribing and adjustment of opioid dose to changing requirements. The choice of first-line opioid is based on scientific evidence, pain pathophysiology, and available administration modes. Doses are calculated on a bodyweight basis up to a maximum absolute starting dose. Morphine remains the gold standard starting opioid in PPC. Long-term opioid choice and dose administration is determined by the pathology, analgesic effectiveness, and adverse effect profile. Slow-release oral morphine remains the dominant formulation for long-term use in PPC with hydromorphone slow-release preparations being the first rotation opioid when morphine shows severe adverse effects. The recently introduced fentanyl transdermal therapeutic system with a drug-release rate of 12.5 microg/hour matches the lower dose requirements of pediatric cancer pain control. Its use may be associated with less constipation compared with morphine use. Though oral transmucosal fentanyl citrate has reduced bioavailability (25%), it inherits potential for breakthrough pain management. However, the gold standard breakthrough opioid remains immediate-release morphine. Buprenorphine is of special clinical interest as a result of its different administration routes, long duration of action, and metabolism largely independent of renal function. Antihyperalgesic effects, induced through antagonism at the kappa-receptor, may contribute to its effectiveness in neuropathic pain. Methadone also has a long elimination half-life (19 [SD 14] hours) and NMDA receptor activity although dose administration is complicated by highly variable morphine equianalgesic equivalence (1 : 2.5-20). Opioid rotation to methadone requires special protocols that take this into account. Strategies to minimize adverse effects of long-term opioid treatment include dose reduction, symptomatic therapy, opioid rotation, and administration route change. Patient- or nurse-controlled analgesia devices are useful when pain is rapidly changing, or in terminal care where analgesic requirements may escalate. In this article, we present detailed pediatric pharmacokinetic and pharmacodynamic data for opioids, their indications and contraindications, as well as dose-administration regimens that include practical strategies for opioid switching and dose reduction. Additionally, we discuss the problem of hyperalgesia and the use of adjuvant drugs to support opioid therapy.

Oral Transmucosal Fentanyl Citrate: Overview of Pharmacological and Clinical Characteristics

Oral transmucosal fentanyl citrate (OTFC; brand name Actiq, Cephalon, UT) is a new opioid formulation that incorporates fentanyl into a lozenge and allows drug delivery through the buccal mucosa. This kind of absorption avoids first-pass metabolism, yielding a bioavailability substantially greater than oral administration. OTFC has a rapid onset of action and a short duration of effect. These characteristics, which resemble the course of a typical breakthrough pain episode, resulted in making OTFC the first opioid analgesic formulation specifically developed and approved for control of breakthrough pain in cancer patients. Apart from that, OTFC has been used in a variety of clinical situations of noncancer pain. This review article presents the synthesis; clinical pharmacology; pharmacokinetic and pharmacodynamic properties, toxicity, and clinical efficacy of this novel agent.

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

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

[Oral transmucosal fentanyl citrate for the treatment of breakthrough pain. Results of a non-interventional study (NIS)]

BACKGROUND

In a non-interventional study the efficacy and tolerability of oral transmucosal fentanyl citrate (OTFC) was studied in patients with opioid-treated cancer pain suffering from breakthrough pain.

PATIENTS AND METHODS

The prospective multicenter observational trial included 406 patients. For 3-4 months, efficacy of OTFC treatment for breakthrough pain was documented using a numerical analog pain intensity scale (NAS). Further, OTFC therapy was rated and adverse events were recorded.

RESULTS

With application of oral transmucosal fentanyl citrate median pain intensity fell from NAS 8 points at the beginning to NAS 2 points at the end of the study. The median effective dosage was 400 g. Tolerability was rated as good or very good by 87.5% of the patients.

CONCLUSION

Oral transmucosal fentanyl citrate is a safe and effective treatment for breakthrough pain in chronic cancer-related pain.

[Cancer pain management. Basic therapy and treatment of breakthrough pain]

Cancer pain imposes a great burden on patients and results in considerable constraints limiting their quality of life. The basic treatment for chronic pain consists in oral administration of long-acting preparations of various analgesic agents according to a set schedule. In addition to chronic pain, however, about 60% of cancer patients also suffer from breakthrough pain. Rapid-onset and short-acting preparations of highly potent opioids are available for the management of these attacks. To choose the correct analgesic agent, it is essential to take a comprehensive medical history and be aware of the different forms of pain present.

Oral transmucosal fentanyl citrate in cancer pain management: a practical application of nanotechnology

Pain is experienced by most cancer patients and represents an important issue in the clinical setting. Breakthrough pain is a transitory flare of pain that occurs in most cancer patients on a background of otherwise controlled persistent pain. Treatment of breakthrough pain is a challenging phenomenon. Oral transmucosal fentanyl citrate (OTFC; Actiq, Cephalon, UK), a new opioid formulation with a unique delivery system, utilizing the advantages that nanotechnology offers, reflects the characteristics of breakthrough pain (rapid onset of action and short duration), which makes it an effective treatment to cancer patients who are already receiving opioids and continue to experience such flares of pain. Oral transmucosal fentanyl citrate is specifically developed and approved for the management of breakthrough pain in cancer patients and it has the potential to be a useful tool for clinicians.

Absolute and relative bioavailability of fentanyl buccal tablet and oral transmucosal fentanyl citrate

This study assessed the absolute and relative bioavailabilities and transmucosal and gastrointestinal absorbency of fentanyl buccal tablet (FBT) and oral transmucosal fentanyl citrate (OTFC). In a randomized crossover design, 26 healthy subjects received FBT 400 microg (transmucosal), FBT 800 microg (oral), OTFC 800 microg (transmucosal), and fentanyl 400 microg (intravenous). The transmucosal FBT had the highest absolute bioavailability (0.65) compared with the oral FBT (0.31) or transmucosal OTFC (0.47). More fentanyl was absorbed transmucosally from FBT than OTFC (48% vs 22%). Median t(max) values were shorter following the transmucosal FBT (47 minutes) than the oral FBT (90 minutes) or the transmucosal OTFC (91 minutes). Transmucosal administration of FBT compared with dose-normalized OTFC resulted in higher total systemic fentanyl exposure, higher early systemic exposure, and higher C(max). The rate and extent of fentanyl absorption were greater following administration of FBT compared to OTFC. An approximately 30% smaller dose of FBT achieved systemic exposures comparable to OTFC.

Critical care sedation for neuroscience patients

In 2000, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) introduced the mandate for the implementation of standards for both pain assessment and need for therapy in hospitalized patients. The need for the appropriate titration of sedation and analgesia is particularly poignant in an intensive care unit (ICU) setting where iatrogenic discomfort often complicates patient management. Neurologically ill patients in ICUs present particularly complex sedation issues, owing to the need to monitor these patients with serial neurological exams. Hence, maximal comfort without diminishing neurological responsiveness is desirable. Here, we review the frequently applied methods of evaluating levels of pain and agitation in critically ill patients as well as discuss the appropriate classes of pharmaceutical agents common to this population, with particular emphasis on the potential neurophysiological impact of such therapy.

Oral transmucosal fentanyl citrate for cancer breakthrough pain: a review

PURPOSE/OBJECTIVES

To review the dose titration, efficacy, and safety of oral transmucosal fentanyl citrate (OTFC).

DATA SOURCES

Phase I and II clinical trial abstracts and evidence-based review articles.

DATA SYNTHESIS

OTFC has an onset, peak, and duration of action similar to that of an IV dose of an opioid and has been demonstrated to be effective and well tolerated for the management of breakthrough pain in patients with cancer.

CONCLUSIONS

Studies of OTFC demonstrate that it is easy to use,noninvasive, effective, safe, and acceptable to patients, caregivers, and healthcare providers. However, OTFC is expensive and approved for use only in opioid-tolerant patients with cancer.

IMPLICATIONS FOR NURSING

Breakthrough pain in patients with cancer is a common problem with characteristics that make it difficult to treat. Oncology nurses should familiarize themselves with OTFC's unique characteristics to be able to best help patients manage their therapy.

Evidence-Based Oral Transmucosal Fentanyl Citrate (OTFC®) Dosing Guidelines

OBJECTIVE

To review the evidence for dosing and efficacy of oral transmucosal fentanyl citrate in the management of pain and produce dosing guidelines.

DESIGN

The scientific literature pertaining to oral transmucosal fentanyl citrate was reviewed, focusing upon its pharmacology and clinical experience with use in cancer and noncancer pain. Emphasis was upon published, peer-reviewed English language articles.

RESULTS

Information was crucially examined and synthesized into guidelines for use and dosing of oral transmucosal fentanyl citrate in cancer and noncancer pain.

CONCLUSIONS

Oral transmucosal fentanyl citrate is a potent opioid delivery system, which, when used appropriately, is an effective treatment option for pain. Adherence to guidelines should promote its safe and efficacious use in a variety of clinical pain management settings.

Oral transmucosal fentanyl citrate for the treatment of breakthrough pain in cancer patients: an overview of its pharmacological and clinical characteristics

Breakthrough pain is a transitory flare of pain occurring in most cancer patients against a background of otherwise controlled persistent pain. Treatment of breakthrough pain is a challenging phenomenon. Oral transmucosal fentanyl citrate (Actiq, Cephalon, Inc, West Chester, PA), a new opioid formulation with a unique delivery system, reflects the characteristics of breakthrough pain (rapid onset of action and short duration), making it an effective treatment for cancer patients who already receive opioids and experience flares of pain. This review article aims to present the role of oral transmucosal fentanyl citrate in the management of breakthrough pain in cancer patients. In particular, it is going to discuss the synthesis, clinical pharmacology, pharmacokinetic and pharmacodynamic properties, toxicity, and clinical efficacy of this novel agent.

[Safety and efficacy of oral trans-mucosal fentanyl citrate in the long-term treatment of breakthrough pain in oncology patients: the ECODIR study]

INTRODUCTION

Oral trans-mucosal fentanyl citrate (OTFC) is the one drug specifically developed for the management of breakthrough pain. This study assesses the long-term safety and efficacy of OTFC standard clinical conditions. Patients and methods. Six-month observational study performed on cancer patients with episodes of breakthrough pain. Safety was assessed by recording the advent of adverse events and efficacy by the evaluating the intensity of breakthrough pain.

RESULTS

174 cancer patients were recruited into the study. All adverse reactions reported were mild or moderate. OTFC was significantly faster (time to the commencement of pain relief: 12.7 +/- 11.4 vs 32.7 +/- 18.4 minutes; p < 0.001) and potent (post-treatment pain intensity: 3.4 +/- 1.5 vs 4.3 +/- 1.5; p < 0.001) than the previously-used drugs.

CONCLUSIONS

This observational study confirms the good safety profile of OTFC as well as its effectiveness over long-term period treatment of breakthrough pain.

Pharmacokinetics and tolerability of different doses of fentanyl following sublingual administration of a rapidly dissolving tablet to cancer patients: a new approach to treatment of incident pain

AIMS

It is estimated that two-thirds of cancer patients will at some point during their illness experience breakthrough pain. In this study, the pharmacokinetics of a novel sublingual dosage form of fentanyl developed for breakthrough pain was evaluated.

METHODS

Eleven Caucasian patients (seven male and 4 female, aged 34-75 years, median 60 years) with metastatic malignant disease were recruited initially, but three patients withdrew. Prior to the study all patients were on continuous nonfentanyl opiate medication. The study was a double-blind, cross-over trial, consisting of three 1-day treatment periods. A new rapidly dissolving preparation of fentanyl, was administered sublingually in single doses of 100, 200 and 400 microg, respectively, on three separate occasions. Plasma fentanyl concentrations were determined using liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Pharmacokinetic parameters were calculated by noncompartment analysis. Tolerability and the occurrence of adverse events were monitored throughout the study by patient questionnaire.

RESULTS

The data from nine subjects who completed at least two periods were used in the analysis of variance. There were no significant differences between doses (100, 200 and 400 microg) for dose adjusted AUC (F = 0.42, P = 0.6660), dose adjusted C(max) (F = 0.08, P = 0.9206) and Tmax (F = 0.94, P = 0.4107). Thus, these parameters showed dose proportionality. The differences (400-100microg) in dose adjusted AUC from the three-period crossover analysis was -0.016 min.ng/ml (t = 0.71, P = 0.8718). Interindividual variability in systemic exposure to fentanyl was fairly small (25-40%), which may be related to a good in vivo biopharmaceutical performance of the sublingual tablet, and a relatively small fraction of the dose being swallowed. The first detectable plasma concentration of fentanyl was observed between 8 and 11 min after administration. t(max) increased from 39.7 +/- 17.4 to 48.7 +/- 26.3 and 56.7 +/- 24.6 min for the 100, 200 and 400 microg doses, respectively. Adverse events were few and did not increase with increasing dose.

CONCLUSION

With this rapidly dissolving fentanyl formulation, the first detectable plasma concentration of fentanyl was observed at 8-11 min after administration. The pharmacokinetics of the drug showed dose proportionately. This formulation of fentanyl seemed to be well tolerated by the patients.

Management of cancer pain

There are four basic approaches to cancer pain control: modify the source of pain, alter central perception of pain, modulate transmission of pain to the central nervous system, and block transmission of pain to the central nervous system. Systemic pharmacologic management aimed at the first three of these approaches is the cornerstone of the treatment of most cancer patients with moderate to severe pain. Optimal pharmacologic management of cancer pain requires selection of the appropriate analgesic drug; prescription of the appropriate dose; administration of the analgesic by the appropriate route; scheduling of the appropriate dosing interval; prevention of persistent pain and relief of breakthrough pain; aggressive titration of the dose of the analgesic; prevention, anticipation, and management of analgesic side effects; consideration of sequential trials of opioid analgesics; and use of appropriate co-analgesic drugs for specific pain syndromes. Most clinicians should be able to control most of the pain in most of their cancer patients. Collaboration with pain and hospice/palliative care experts should help the rest. No cancer patient should live or die with unrelieved pain.

Oral transmucosal fentanyl citrate for the treatment of migraine headache pain in outpatients: a case series

BACKGROUND

Migraine headache pain that does not respond to traditional antimigraine medications frequently requires treatment in the emergency department (ED) with parenteral opioids. Rapid onset of pain relief in an outpatient setting for migraine headache is the primary objective of patients and clinicians. Oral transmucosal fentanyl citrate (OTFC; ACTIQ) is a novel opioid product designed to deliver rapid analgesia to patients who experience breakthrough pain (BTP).

OBJECTIVE

To evaluate the effectiveness, tolerability, and patient satisfaction with OTFC for the outpatient treatment of acute, refractory migraine headache pain.

PATIENTS AND METHODS

Twenty patients with recurrent acute, refractory migraine headaches who had been referred to this headache clinic are reported in this case series. All patients had a history of tolerating parenteral opioids in the ED when experiencing refractory migraine pain and had been treated with outpatient opioid therapies in attempts to manage their migraine pain. Patients were prescribed OTFC (400 microg) as rescue treatment for moderate or severe migraine headache pain as outpatients. Patients were instructed to self-administer OTFC at home and complete a diary recording: pain intensity (11-point scale; 10 = worst pain imaginable to 0 = no pain) before and 15, 30, 60, and 120 minutes after OTFC; satisfaction with the effectiveness of OTFC (selecting 1 of 7 categories ranging from "very dissatisfied" through "very satisfied") rated at 120 minutes; and adverse events.

RESULTS

Eighteen patients (13 female) experienced a migraine and self-administered OTFC. OTFC successfully treated migraine episodes in all 18 outpatients; no patient went to an ED. OTFC rapidly reduced pain intensity, with significant improvement at 15 minutes that was sustained and provided progressively more pain relief at 30, 60, and 120 minutes (all P <.01). Mean (SEM) pain intensity significantly declined from 8.83 (0.35) pretreatment to 2.28 (0.67) at 120 minutes, an average reduction of 75% (P <.01). Patients' satisfaction ratings with OTFC were overwhelmingly positive, with 94% being satisfied and more than half (56%) being "very satisfied." Three (17%) patients experienced nausea, two (11%) somnolence, and one (6%) each itching, vomiting, and dry mouth. All adverse events were mild or moderate in severity.

CONCLUSIONS

OTFC rapidly and significantly relieved acute, refractory migraine pain in outpatients, prevented the need for an ED visit, and was associated with high patient satisfaction ratings. The rapid onset of migraine headache pain relief in this case series is consistent with the analgesic effect reported with the use of OTFC in patients with BTP. OTFC was well tolerated in these patients who had a history of tolerating parenteral opioids in the ED when experiencing refractory migraine pain and had been treated with outpatient opioid therapies in attempts to manage their migraine pain. OTFC may be effective for outpatient treatment of acute, refractory migraine headache pain. Further controlled studies are warranted.

Clinical effects and plasma concentrations of fentanyl after transmucosal administration in three species of great ape

Fentanyl is approved for transmucosal use in the United States as a preanesthetic agent in human pediatric patients and in adults for breakthrough cancer pain. Using this formulation in three species of great ape, including eight orangutans (Pongo pygmaeus), nine chimpanzees (Pan troglodytes), and two gorillas (Gorilla gorilla), fentanyl was offered transmucosally at an intended dose of 10-15 microg/kg based on estimated body weight. The animals were trained to accept and suck slowly on a piece of placebo candy, given as a treat, after an overnight fast. On the day of the study, the animals were given the lollipop formulation of fentanyl. The resulting plasma concentrations of fentanyl supported transmucosal absorption, similar to that reported in humans. This study provides an alternative sedative regimen and yielded half-life data of transmucosal fentanyl in great apes. Although transmucosal fentanyl was a useful adjunct for sedating orangutans and gorillas, its acceptance by chimpanzees before chemical immobilization was suboptimal and unpredictable.

Oral transmucosal fentanyl citrate in the outpatient management of severe cancer pain crises: a retrospective case series

OBJECTIVE

This retrospective chart review evaluated the efficacy of oral transmucosal fentanyl citrate (OTFC) in an outpatient cancer pain center for patients experiencing severe exacerbations of pain that exceed usual breakthrough pain levels.

PATIENTS

Records were reviewed for all patients who received OTFC at M.D. Anderson's outpatient pain clinic over a three-month time period. OTFC was used in thirty-nine patients experiencing a recent onset of severe pain (> or =7 on a 0-10 scale). All patients had cancer, cancer-related pain syndromes, and were opioid tolerant with an oral morphine equivalent daily dosage (MEDD) of (> or =40 mg/day.

RESULTS

Prior to OTFC treatment, all patients reported a mean pain intensity of 9.0 (SD = 1.2). After OTFC treatment, patients reported a mean intensity of 3.0 (SD = 1.4), a significant reduction in pain intensity (P < 0.001). In most cases, OTFC averted the need for an emergency center visit, parenteral opioids, and hospital admission, which suggests that OTFC may be an effective alternative over intravenous opioids to rapidly titrate analgesia in selected opioid-tolerant cancer patients experiencing severe pain.

Simultaneous extraction and quantitation of fentanyl and norfentanyl from primate plasma with LC/MS detection

The quantitation of both fentanyl and its desalkyl metabolite, norfentanyl, in plasma using LC/MS has not been previously described. The detection and quantitation of fentanyl and norfentanyl was achieved using LC/MS detection. The liquid-liquid extraction used toluene as the organic phase. Chromatography was carried out using a Zirchrom-PBD (50 mm x 2.1 mm, 3 microm) column with a mobile phase of acetonitrile-ammonium acetate (10 mM), citrate (0.1 mM, pH 4.4) (45:55, v/v) with a flow rate of 0.3 ml/min. Mass spectroscopy detection was performed using ESI in the positive mode. The LOQ for fentanyl was 25 pg/ml and norfentanyl was 50 pg/ml. For the concentrations of 75, 250, and 750 pg/ml, respectively, fentanyl had inter-day precisions of 6.6, 7.2, and 6.6% with accuracies of 4.0, 5.1, and 5.1% and intra-day precisions of 1.6, 1.9, and 1.9% with accuracies of 11.6, 9.4, and 8.4%, and norfentanyl had inter-day precisions of 7.4, 0.3, and 0.7% with accuracies of 9.1, 8.8, and 12.3% and intra-day precisions of 5.3, 1.4, and 0.1% with accuracies of 10.9, 8.9, and 12.8%. The recoveries of fentanyl were 85, 92, and 75% and of norfentanyl were 40, 49, and 46% at the 75, 250, and 750 pg/ml concentrations, respectively.

Self-treatment with oral transmucosal fentanyl citrate to prevent emergency room visits for pain crises: patient self-reports of efficacy and utility

Ninety (90) patients with chronic pain who were treated with a long-acting opioid were instructed on use of oral transmucosal fentanyl citrate (OTFC) for self-treatment of emergency pain flares. Eighty-six (95.6%) believed OTFC was effective and safe for self-treatment of emergency pain flares, and 71 (78.8%) believed they had prevented one or more emergency room visits for treatment of pain flares. A subgroup of 45 patients who had collectively used OTFC for 375 months, based on their past experience, estimated they had prevented 1.26 emergency room visits per month per patient. OTFC should be further studied for cost-savings and effectiveness in self-treatment of emergency pain flares.

In vitro and in vivo evaluation of a new sublingual tablet system for rapid oromucosal absorption using fentanyl citrate as the active substance

Oromucosal delivery of drugs promotes rapid absorption and high bioavailability, with subsequent almost immediate onset of pharmacological effect. However, many oromucosal delivery systems are compromised by the possibility of the patient swallowing the active substance before it has been released and absorbed locally into the systemic circulation. This paper introduces a new tablet system for sublingual administration and rapid drug absorption. The tablet is based on interactive mixtures of components, consisting of carrier particles partially covered by fine dry particles of the drug, in this case fentanyl citrate. In the interests of increasing retention of the drug at the site of absorption in the oral cavity, a bioadhesive component was also added to the carrier particles. Tablets containing 100, 200 and 400 microg of fentanyl were tested both in vitro and in vivo. The tablets disintegrated rapidly and dissolution tests revealed that fentanyl citrate was dissolved from the formulation almost instantly. Plasma concentrations of fentanyl were obtained within 10 min, with no second peak. These results indicated that the bioadhesive component prevented the fentanyl from being swallowed (the fraction swallowed was considered smaller compared to other mucosal delivery systems), without hindering its release and absorption. This new sublingual tablet formulation may also hold potential for other substances where a rapid onset of effect is desirable.

A pharmacokinetic study to compare two simultaneous 400 microg doses with a single 800 microg dose of oral transmucosal fentanyl citrate

It is unknown whether two smaller doses of oral transmucosal fentanyl citrate (OTFC) administered simultaneously are pharmacokinetically equivalent to an identical dose administered as a single unit. This issue has important practical implications when patients are attempting to identify the appropriate dosage of OTFC to control their pain. This open-label, randomized, crossover design study compared the pharmacokinetics of two simultaneously consumed 400 microg OTFC doses with one 800 microg OTFC dose in 12 healthy volunteers. The two treatments were pharmacokinetically equivalent. The maximum concentration produced for each dosage group (Cmax) was 1.09 ng/ml for two 400 microg dose and 1.10 ng/ml for one 800 microg dose. Area under the curve (AUC) was 8.2 ng/ml.hr (SE=1.1) and 7.2 ng/ml.hr (SE=1.0). There were no significant differences between the treatment groups in either the time to peak concentration (Tmax) or the mean residence time (MRT). The results demonstrate the bioequivalence of two 400 microg with one 800 microg OTFC units.

Pharmacotherapy of cancer-related episodic pain

Episodic pain is a transient increase in pain intensity over background pain. Episodic pain occurs commonly in cancer patients; it is a heterogeneous phenomenon that is incapacitating, debilitating and can have a significant impact on quality of life. Episodic pain can be difficult to manage; it is often unpredictable, typically of fast onset, of short duration and feels similar to background pain except that it may be more severe. The successful management of episodic pain can only be achieved following a thorough assessment. The subsequent management usually involves both pharmacological and non-pharmacological strategies integrated into the overall care and appropriate for the stage of the patient's disease. Pharmacological management includes the implementation of primary therapies (e.g., chemotherapy for the underlying aetiology of the pain, optimising the scheduled medication (e.g., analgesics and adjuvant analgesics) and specific pharmacological interventions for the episodic pain (e.g., rescue medication).

Oral mucosal drug delivery: clinical pharmacokinetics and therapeutic applications

Oral mucosal drug delivery is an alternative method of systemic drug delivery that offers several advantages over both injectable and enteral methods. Because the oral mucosa is highly vascularised, drugs that are absorbed through the oral mucosa directly enter the systemic circulation, bypassing the gastrointestinal tract and first-pass metabolism in the liver. For some drugs, this results in rapid onset of action via a more comfortable and convenient delivery route than the intravenous route. Not all drugs, however, can be administered through the oral mucosa because of the characteristics of the oral mucosa and the physicochemical properties of the drug. Several cardiovascular drugs administered transmucosally have been studied extensively. Nitroglycerin is one of the most common drugs delivered through the oral mucosa. Research on other cardiovascular drugs, such as captopril, verapamil and propafenone, has proven promising. Oral transmucosal delivery of analgesics has received considerable attention. Oral transmucosal fentanyl is designed to deliver rapid analgesia for breakthrough pain, providing patients with a noninvasive, easy to use and nonintimidating option. For analgesics that are used to treat mild to moderate pain, rapid onset has relatively little benefit and oral mucosal delivery is a poor option. Oral mucosal delivery of sedatives such as midazolam, triazolam and etomidate has shown favourable results with clinical advantages over other routes of administration. Oral mucosal delivery of the antinausea drugs scopolamine and prochlorperazine has received some attention, as has oral mucosal delivery of drugs for erectile dysfunction. Oral transmucosal formulations of testosterone and estrogen have been developed. In clinical studies, sublingual testosterone has been shown to result in increases in lean muscle mass and muscle strength, improvement in positive mood parameters, and increases in genital responsiveness in women. Short-term administration of estrogen to menopausal women with cardiovascular disease has been shown to produce coronary and peripheral vasodilation, reduction of vascular resistance and improvement in endothelial function. Studies of sublingual administration of estrogen are needed to clarify the most beneficial regimen. Although many drugs have been evaluated for oral transmucosal delivery, few are commercially available. The clinical need for oral transmucosal delivery of a drug must be high enough to offset the high costs associated with developing this type of product. Drugs considered for oral transmucosal delivery are limited to existing products, and until there is a change in the selection and development process for new drugs, candidates for oral transmucosal delivery will be limited.

A comparison of oral transmucosal fentanyl and oral midazolam for premedication in children

Oral transmucosal fentanyl citrate (OTF) was compared with midazolam as a premedicant in a prospective, randomised, placebo-controlled, double-blind trial. Eighty children (ASA grade 1 or 2, aged 3-9 years) who presented for tonsillectomy were randomly allocated to receive either 2.5 ml OTF (15-20 microg.kg(-1)) in a lollipop format and 0.5 ml.kg(-1) placebo syrup, or midazolam syrup (0.5 mg.kg(-1)) and a placebo lollipop (2.5 ml). The acceptability of sedation, anxiety and compliance with anaesthetic induction were assessed. The children were given an 'emergence' score for their recovery. Analgesia requirements, the incidence of vomiting, itching and any behavioural changes were assessed for 6 h postoperatively. Oral transmucosal fentanyl citrate was as effective as midazolam in aiding compliance with anaesthesia, but is significantly better in its appeal to children (p < 0.001) and emergence (p < 0.001) characteristics. In conclusion, OTF may be particularly useful as a premedicant in paediatric practice.

Recent advances in pharmacotherapy for cancer pain management

PURPOSE

This review provides an outline of several recent advances in drug treatment options and strategies for managing cancer pain.

OVERVIEW

The development of cyclooxygenase-2-selective nonsteroidal anti-inflammatory drugs (NSAIDs) and transmucosal fentanyl citrate provide new pharmacologic options for the treatment of cancer pain. Combinations of opioid agonists and antagonists have provided data on new strategies to balance effective analgesia with analgesic-related adverse effects. In addition, the spectrum of adjuvant agents for the treatment of neuropathic pain has been extended to various antidepressants and topical analgesics. There is continued research on the role of the N-methyl-d-aspartate (NMDA) receptor and, specifically, on NMDA receptor antagonists that may augment analgesia and combat opioid resistance. Finally, a more potent generation of bisphosphonates may lead to improved pain relief for patients with bone metastases.

CLINICAL IMPLICATIONS

With a combination of emerging new clinical research and professional practice experience of the cancer care team, new strategies will continue to be developed and implemented, resulting in the continued improved care of patients with cancer.

Strategies for the treatment of cancer pain in the new millennium

As was the case in the era before us, in the new millennium we will continue to see an abundance of patients experiencing cancer-related pain for different reasons. Although much needless pain and suffering still affects many of those with cancer, we are presented with a medical dichotomy. With the analgesic drugs available today, and the relatively simple and effective guidelines to treat cancer pain published and disseminated by the World Health Organization, why do people with cancer continue to experience pain? As we search for the answer, the horizon may hold promising new drugs, 'old drugs' with new interest and applications, and new strategies for the field of pain therapy. Possibilities include the isolation and development of analgesics or analgesic combinations that may minimise the adverse effects which are often associated with the current therapeutic class of opioid analgesics. In addition, current research points to promising results identifying the N-methyl D-aspartate non-opioid receptor as a likely component of neuropathic pain. Drugs such as gabapentin, the mechanism of action of which is not well known, have found favour within the clinical community for their analgesic properties and good tolerability. Methadone, in a phase of resurgence, has garnered the attention of the clinical community because of its unique receptor activity and pharmacoeconomic benefits. A number of clinical studies have demonstrated that methadone has a valuable role in treating cancer pain. Perhaps, an unbalanced focus on the risks of inappropriate use, rather than the benefits, should not compromise or distract from the use of methadone as an alternative to morphine. Studies are on going to assess the potential role of methadone in treating neuropathic pain. Drugs such as cannabinoids, although currently applicable for patients with anorexia, nausea and/or vomiting, may offer benefits to patients experiencing pain. Other opportunities exist with such compounds as alpha2-adrenergic agonists, nicotine, lidocaine and ketamine. New strategies such as the switching opioids and/or their route of administration may offer improved analgesia with fewer adverse effects, thus providing therapeutic alternatives for the clinical community. In addition, there is interest in the co-administration of opioids that act on different receptors. For instance, oxycodone appears to be a kappa opioid receptor agonist and may offer enhanced analgesia when combined with morphine.