Transdermal fentanyl: an updated review of its pharmacological properties and therapeutic efficacy in chronic cancer pain control

Postoperative pain management with a patient-controlled transdermal delivery system for fentanyl

PURPOSE

The efficacy and safety of fentanyl hydrochloride patient-controlled trans-dermal system (PCTS) for management of acute postoperative pain are discussed.

SUMMARY

Fentanyl hydrochloride PCTS is a self-contained, needle-free, credit-card-sized fentanyl-delivery system that is worn on the patient's arm or chest. The system uses iontophoretic technology to actively deliver preprogrammed doses of fentanyl into the systemic circulation when activated by the patient on demand. PCTS is as safe and effective as i.v. morphine patient-controlled analgesia and superior to placebo for managing acute postoperative pain. Fentanyl absorption from PCTS is clinically insignificant when the device is not activated. This contrasts with the transdermal fentanyl patch, which delivers fentanyl continuously for 72 hours via passive absorption and is indicated only for use in the management of chronic pain.

CONCLUSION

Fentanyl hydrochloride PCTS is a self-contained iontophoretic fentanyl-delivery system that provides patients control over pain management and consistent management of pain without analgesic peaks and troughs.

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

Matrix systems for transdermal fentanyl will replace the reservoir systems in Europe. In an industry-independent, prospective, multicenter pilot study, 46 outpatients with chronic pain were asked to assess pain intensity, sleep interference, adverse events, and multiple secondary parameters during administration of the last reservoir and the first two matrix patches. There was no difference in pain intensity, sleep interference, and the rate of adverse events between both systems. Self assessment on a 6-step numeric rating scale (1 = very good, 6 = insufficient) comparing the two systems (reservoir vs. matrix) showed that skin compatibility (2.6 vs. 1.5), adhesive properties (3.2 vs. 1.8), wearability/comfort (2.8 vs. 1.5), and general satisfaction (2.5 vs. 1.8) improved significantly with the new matrix technology. At study endpoint, 91% of patients preferred the matrix system for future use. The new fentanyl matrix system is characterized by a high level of general satisfaction, ease of use, patient acceptance, and improved skin compatibility. Reservoir and matrix systems appear to have comparable efficacy and safety so that outpatients can be switched directly from the reservoir to the matrix system without difficulties and new dose titration.

Changes in the Prescribed Daily Doses of Transdermal Fentanyl and Transdermal Buprenorphine During Treatment of Patients with Cancer and Noncancer Pain in Germany: Results of a Retrospective Cohort Study

BACKGROUND

During long-term therapy with strong opioids (step III opioids according to the World Health Organization [WHO] analgesic ladder), dose increases are often necessary because of deterioration of the primary disease or development of tolerance.

OBJECTIVE

The purpose of this study was to compare changes in dosages of transdermal (TD) fentanyl and TD buprenorphine in patients with cancer and non-cancer pain.

METHODS

In a retrospective study, patients with cancer and noncancer pain being treated with TD fentanyl or TD buprenorphine for at least 3 months between January 2001 and December 2003 were identified from the IMS Disease Analyzer-mediplus database, which contains all patient-related data documented from 400 medical practices in Germany. The indications for treatment were defined according to the International Classification of Diseases, 10th Revision, and included neoplasm (cancer groups), and osteoarthritis, low back pain, and osteoporosis (noncancer groups). The cohort patients were considered to have comparable pain intensity because they had received similar analgesic premedication classified according to steps I to III of the WHO analgesic ladder (cohort groups). The mean prescribed daily doses on first and last prescription were documented, and the mean percentile increases were calculated over the whole treatment duration and per day. Additionally, the mean percentile intraindividual increases (on a per-patient basis) were estimated.

RESULTS

The cohort groups consisted of 448 patients with noncancer pain and 446 patients with cancer pain (552 women and 342 men; mean age, 74 years; range, 25-101 years). The mean percentile increases in dosages over the whole treatment duration and adjusted per day were significantly higher in patients taking TD fentanyl (P < 0.05). Differences were even greater for the mean percentile intraindividual increases per day, which totaled 0.42%and 0.17% for cancer patients taking TD fentanyl and TD buprenorphine, respectively; corresponding values were 0.25% and 0.09%in noncancer patients (P < 0.001).

CONCLUSIONS

This retrospective analysis showed a significantly higher increase in the mean daily doses of TD fentanyl as compared with TD buprenorphine. The results must be verified in prospective, randomized clinical studies.

Chronic fentanyl application induces adrenocortical insufficiency

We report a case of a 64-year-old man with secondary adrenocortical insufficiency who has been on a chronic transdermal fentanyl treatment because of sciatic pain syndrome. Shortly before admission to our hospital, the patient had discontinued his hydrocortisone medication. Adrenal crisis was assumed and during therapy with hydrocortisone infusion, the patient recovered. We suspected an opiate-induced suppression of the hypothalamus-pituitary-adrenal (HPA) axis. Therefore, we gradually reduced the opiate dosage. After 1 week, HPA axis function was markedly improved. We conclude that opiate medication may inhibit - in a life-threatening way - the organism's ability to respond to physical, emotional or metabolic stressors.

The Role of Opioids in Cancer Pain Management

Opioids remain an important cornerstone in the treatment of cancer pain. Effective analgesia is obtained in the majority of cancer pain patients with the application of fairly straightforward algorithms using opioids as the main therapy. Many rational treatment algorithms exist. In this tutorial we will describe the role of opioids in the treatment of cancer pain, including a brief overview of cancer pain syndromes, essential aspects of opioid therapy, opioid pharmacology, opioid rotation, properties of the individual opioids, and management of common side effects of opioids.

Practice guidelines for transdermal opioids in malignant pain

Patients with moderate-to-severe malignancy-related pain require opioid pharmacotherapy. Many cancer patients continue to be prescribed subtherapeutic doses of pain medications resulting in undue suffering and diminished quality of life. Pain associated with malignancy and its treatment may exacerbate other symptoms associated with cancer, including nausea, fatigue, weakness, dyspnoea, constipation and impaired cognition. The choice of analgesic pharmacotherapy should be individualised and based on the intensity of pain reported by the patient, rather than its specific aetiology. When selecting pain management pharmacotherapy, the healthcare provider should consider the patient's pain level, activity level and any comorbid illness. Intolerable adverse effects, ineffective pain relief or a change in the patient's clinical status can dictate the need for a new pain management regimen. Healthcare providers must be able to readily quantify the relative analgesic potency when converting from one opioid to another or from one route of administration to another. Transdermal formulations of fentanyl and buprenorphine are effective pharmacotherapy that can be safely used for cancer patients with pain. However, clinicians need to be cognisant that the US/UK manufacturer's recommendations for equianalgesic dose administration of transdermal fentanyl may result in initial doses that produce subtherapeutic concentrations and unrelieved pain in some patients. A less conservative dose administration algorithm for transdermal fentanyl using a 2:1 (mg/day of oral morphine : microg/h of transdermal fentanyl) conversion ratio that considers both a review of the literature and clinical experience should help clinicians individualise cancer pain pharmacotherapy.

Utilisation pattern of fentanyl transdermal system in The Netherlands

PURPOSE

To describe the utilisation pattern of TTS fentanyl in daily practice.

METHODS

A retrospective cohort study was performed with data from the Dutch PHARMO system, including medication and hospital admission records of 850,000 inhabitants of 25 Dutch cities. New starters of TTS fentanyl with at least two consecutive prescriptions in the period of 1 January 1996 through 31 December 2001 were included in the study cohort. Patients were distinguished in having non-cancer or cancer pain.

RESULTS

About 61% of the patients suffered from non-cancer pain and 60% used other opioids before start of TTS fentanyl. The majority of the patients used other pain medication during the first treatment episode. Most patients (74%) started treatment with the lowest dose of TTS fentanyl (25 microg/hour), patients with cancer pain more often started with higher doses. About half of the patients changed type of patch during the first treatment episode, 80% of these patients had an increase in dose of TTS fentanyl. Fifty percent of all patients had a first treatment episode of less than 2 months and more than one third did not renew their prescription within two months. The median number of days of use per patch was 2.2 days for all patients.

CONCLUSIONS

The use of TTS fentanyl is limited to a short period of time for a substantial percentage of patients starting treatment. The median duration of use per TTS fentanyl patch i.e. 2.2 days, was lower than the 3 days application period recommended in the summary of product characteristics.

Vesicles as a tool for transdermal and dermal delivery

Transdermal and dermal drug delivery is problematic because the skin, as a natural barrier, has a very low permeation rate. Therefore several methods have been assessed to increase this rate locally and temporarily. One approach is the use of vesicle formulations. In this paper the effectiveness of conventional and deformable vesicles as drug delivery systems as well as their possible mode of action as permeation enhancers or transdermal drug carriers will be discussed.:

Identification of fentanyl, alfentanil, sufentanil, remifentanil and their major metabolites in human urine by liquid chromatography/tandem mass spectrometry for doping control purposes

Since January 2005, the list of prohibited substances established by the World Anti-Doping Agency prohibits the opioid agent fentanyl as well as its related drugs in professional and amateur sports. Fast, reliable and robust analytical assays are required that allow the sensitive determination of these compounds or respective metabolites in human urine, and liquid chromatography interfaced to mass spectrometry has proven to be a suitable and powerful tool for drug testing for several years. A screening and confirmation method was developed that enables the identification of fentanyl, alfentanil, remifentanil and sufentanil as well as their N-dealkylated or de-esterified metabolites utilizing solid-phase extraction of a 2 mL urine aliquot followed by LC-electrospray-MS/MS analysis. The procedure was validated in terms of recovery (95.8-104.9%), lower limit of detection (0.5 ng mL-1), specificity and interday precision (3.9-19.8%) for the four opioid drugs and the metabolic product norfentanyl. In addition, the mass spectrometric behavior of fentanyl after electrospray ionization and collision-induced dissociation was studied by synthesis and analysis of structurally related compounds, and dissociation pathways were proposed allowing the characterization of target analytes and corresponding metabolites.

Managing pain in feline patients

In the past 10 years, great strides have been made in the field of feline analgesia. A better understanding of the cat's unique metabolism has led researchers to realize that extrapolation across species boundaries is unwise,and this has resulted in feline-specific studies. The opioids are now used more commonly in cats, with good analgesic effect and few side effects. Excellent acute pain management is achievable in cats by using opioids, NSAIDs, alpha2-agonists, and local anesthetics. Although much of the research data has compared the use of single drugs, a multimodal approach using agents that work at different parts of the pain pathway is commonly used in clinical settings, with added benefit. Compared with dogs, few pain-scoring systems have been developed for cats, and this remains an important goal. Management of chronic pain in cats is a challenge because of the potential problems with long-term NSAID use; however, reports of low doses given at extended intervals are encouraging. As we gain experience with less traditional analgesics, such as amitriptyline, amantadine, and gabapentin, and critically evaluate complimentary therapies, our ability to provide comfort to this population of cats will improve.

Managing breakthrough pain: a clinical review with three case studies using oral transmucosal fentanyl citrate

Pain management begins with the use of appropriate assessment tools and includes planning, implementing, and evaluating a comprehensive treatment plan that addresses persistent and breakthrough pain. Persistent pain is present to some degree throughout the day and primarily is controlled with around-the-clock medication. However, it often is accompanied by episodes of short, intermittent pain, also known as breakthrough pain. From a clinical perspective, breakthrough pain is characterized as a transitory exacerbation of pain that occurs on a background of otherwise stable pain in a patient receiving chronic opioid therapy. Breakthrough pain typically is moderate to severe in intensity and can be triggered by various activities (incident pain), be entirely unpredictable (idiopathic pain), or occur toward the end of around-the-clock medication (end-of-dose failure). Breakthrough pain occurs in as many as 86% of patients with cancer even when persistent pain is well controlled. Clinicians and patients should address persistent and breakthrough pain as distinct entities to accurately assess it and develop appropriate pain management plans. This article provides an overview of the clinical characteristics of persistent and breakthrough pain and, through the use of three case studies, illustrates practical strategies for managing breakthrough pain effectively.

Pain management in cats--past, present and future. Part 2. Treatment of pain--clinical pharmacology

Opioids have an unjustified reputation for causing mania in cats, but with refinements in dosing they are now used successfully in this species. The mu-opioid agonists are generally considered the best analgesics. Morphine (0.1-0.3 mg/kg) is effective in a clinical setting. Methadone (up to 0.5 mg/kg) has a similar profile to morphine. Pethidine (Demerol, meperidine; 2-5 mg/kg) is a useful analgesic with a faster onset but shorter duration of action than morphine. Oxymorphone and hydromorphone (0.05-0.1 mg/kg) are widely used in the USA. These opioids are more potent (up to 10 times), and longer acting than morphine in cats. Butorphanol (0.1-0.4 mg/kg) is a mu-opioid antagonist that produces its analgesic actions through kappa agonist activity. It rapidly reaches a ceiling effect, is short acting and is a weaker analgesic than pure mu opioids. Buprenorphine (0.01-0.02 mg/kg), a partial mu-agonist, is the most popular opioid used in small animal practice in the UK, other parts of Europe, Australia and South Africa. In clinical studies it has produced better analgesia than several other opioids and appears to be highly suitable for perioperative pain management in cats. NSAIDs are also used in cats for pain management, although cats metabolise these differently from other species. With appropriate dosing, carprofen (1-4 mg/kg) and meloxicam (0.3 mg/kg) have proved highly effective with few side effects. The use of ketoprofen (2 mg/kg), tolfenamic acid (4 mg/kg) and vedaprofen (0.5 mg/kg) has been reported in cats. Other less traditional analgesics such as ketamine, medetomidine and local anaesthetics are also used for clinical pain management. The transmucosal, transdermal and epidural routes offer novel methods for administration of analgesic drugs and have considerable potential for improving techniques in feline pain management.

Effects of NMDA receptor antagonists on acute mu-opioid analgesia in the rat

Mixed research findings have led to a debate regarding the effect of N-methyl-D-aspartate (NMDA) receptor antagonists on opiate analgesia. NMDA antagonists have been found in various studies to enhance, to inhibit, or to have no effect on opiate analgesia. The present research used a single protocol to explore the effects of six NMDA receptor antagonists on acute morphine (3.0 mg/kg s.c.) and fentanyl (0.05 mg/kg s.c.) analgesia in adult male Sprague-Dawley rats. NMDA receptor antagonists were selected based on their abilities to block various sites on the NMDA receptor complex, including the noncompetitive antagonists MK-801 (0.1 and 0.3 mg/kg i.p.), dextromethorphan (10.0 and 30.0 mg/kg i.p.), and memantine (3.0 and 10.0 mg/kg i.p.), a glycine site antagonist, (+)-HA-966 (10.0 and 30.0 mg/kg i.p.), a competitive antagonist, LY235959 (1.0 and 3.0 mg/kg i.p.), and a polyamine site antagonist, ifenprodil (1.0 and 3.0 mg/kg i.p.). Analgesia was assessed using the tail-flick test. A single dose of each opiate was used. The low doses of the antagonists, which are known to produce significant neural and behavioral actions at NMDA receptors, had no effect on morphine or fentanyl analgesia. At the higher doses, morphine analgesia was significantly enhanced by LY235959 (3.0 mg/kg), and fentanyl analgesia was significantly enhanced by LY235959 (3.0 mg/kg), dextromethorphan (30.0 mg/kg), and (+)-HA-966 (30.0 mg/kg). Enhancement of analgesia occurred without any apparent adverse side effects. None of the NMDA antagonists affected tail-flick responses on their own, except the higher dose of LY235959 (3.0 mg/kg), which produced a mild analgesic effect. Because no consistent effects were observed, the data suggest that NMDA receptors are not involved in acute mu-opioid analgesia. The mechanisms underlying the enhancement of opiate analgesia by selected NMDA antagonists, such as LY235959, dextromethorphan, and (+)-HA-966, remain to be determined.

Oral transmucosal abuse of transdermal fentanyl

Transdermal fentanyl is an opioid analgesic that is effective on chronic pain, and which appears to be advantageous due to several factors such as ease of administration, the relatively stable serum concentration and long dose intervals. Nevertheless, the danger of abuse and dependence exists among patients who are prescribed fentanyl patches. We present a case of transdermal fentanyl abuse, where the administration route of the drug was changed. Our patient, who had no history of substance abuse and who suffered from chronic nonmalignant pain, used the fentanyl transdermal patches as oral transmucosal medication, raising the dose by ten-fold. This abuse of the drug was only for analgesic purposes without seeking anxiolysis and/or euphoria. After treatment and progressive reduction of fentanyl, the patient remains in good condition, and is currently taking the initial dose of the drug transdermally, without having experienced any withdrawal symptoms.

The Safety and Efficacy of a Fentanyl Patient-Controlled Transdermal System for Acute Postoperative Analgesia: A Multicenter, Placebo-Controlled Trial

A noninvasive method of delivery of parenteral opioids for management of acute pain may offer logistic advantages for patients and nursing staff. A patient-controlled transdermal system (PCTS) under development consists of a preprogrammed, self-contained drug-delivery system that uses electrotransport technology (E-TRANS, ALZA Corp, Mountain View, CA) to deliver 40 micro g of fentanyl HCl over 10 min per on-demand dose for patient-controlled analgesia (PCA). In this randomized, double-blinded, placebo-controlled trial we compared the efficacy and safety of on-demand fentanyl HCl PCTS 40 microg against placebo for postoperative pain up to 24 h after major abdominal, orthopedic, or thoracic surgery in 205 patients. The primary efficacy measurement was the percentage of patients withdrawn from the study because of inadequate analgesia after completing at least 3 h of treatment. Secondary efficacy measures included mean pain intensity (using visual analog scales), patient global assessments, and investigator global assessments. Of 189 patients considered evaluable for efficacy, 25% of patients in the fentanyl HCl PCTS 40 microg group withdrew because of inadequate analgesia, compared with 40.4% of the placebo group (P < 0.05). Use of fentanyl HCl PCTS 40 micro g was associated with lower VAS scores and higher mean patient and investigator global assessment scores compared with placebo. No patient experienced clinically relevant respiratory depression. This study showed that a fentanyl HCl PCTS 40 microg for PCA was superior to placebo and well tolerated for the control of moderate to severe postoperative pain for up to 24 h after major surgery.

IMPLICATIONS

This multicenter, randomized, double-blinded, placebo-controlled trial showed that an on-demand fentanyl HCl patient-controlled transdermal system (PCTS) was superior to placebo and well tolerated for the control of moderate to severe postoperative pain for up to 24 h after major surgery. This fentanyl HCl PCTS is a preprogrammed, needle free, self-contained drug-delivery system that uses electrotransport technology (iontophoresis) to deliver 40 microg of fentanyl per on-demand dose.

Transdermal fentanyl: informed prescribing is essential

While morphine is historically the gold standard for the management of severe cancer pain, some patients either do not achieve adequate analgesia, or suffer intolerable side-effects. For these patients an alternative opioid is recommended. One such alternative is the potent mu opioid agonist fentanyl, delivered in a transdermal controlled release formulation. Similar to morphine, transdermal fentanyl is effective for the management of moderate to severe cancer pain. However, inappropriate prescribing of transdermal fentanyl, particularly in the clinical setting of unstable pain, can cause significant opioid toxicity, as highlighted in the case reports described.

Agitated Terminal Delirium and Association with Partial Opioid Substitution and Hydration

BACKGROUND

Delirium is often a distressing symptom for both patients and their families, and its prevention is important. The primary aim of this study was to clarify the effects of partial opioid substitution and hydration on the occurrence of agitated delirium in the final stage of cancer.

METHODS

An historical control study on consecutive terminally ill cancer patients admitted to a palliative care unit (164 in 1996-1997 and 120 in 2000-2001). In 2000-2001, we actively performed hydration and partial opioid substitution from morphine with fentanyl on individual grounds. Two independent raters evaluated the degree of agitation and cognitive impairment during the final week, using the Memorial Delirium Assessment Scale, the Agitation Distress Scale, the Communication Capacity Scale, and a consciousness scale.

RESULTS

Compared to 1996-1997, in 2000-2001, the use of artificial hydration (33% to 44%, p = 0.053) and opioid rotation (3.0% to 41%, p < 0.01) increased, while there were no statistically significant differences in hydration volume, the mean dose, and the high-dose requirements of morphine. The prevalence of agitated delirium, the agitation score, the percentage of patients achieving clear-complex communication, and the percentage of patients who maintained clear consciousness did not significantly change.

CONCLUSIONS

Partial opioid substitution with fentanyl and moderate levels of hydration had no significant preventive effects on the occurrence of agitated delirium in the last week on a mass level. We should explore new strategies to prevent agitated delirium that are practically available in Japan.

Pharmacokinetics of fentanyl following intravenous and transdermal administration in horses

REASONS FOR PERFORMING STUDY

Although fentanyl has been reported to cause CNS excitation in horses, a transdermal therapeutic system (TTS) containing this mu agonist has recently been used empirically in equine medicine to treat moderate to severe pain. A better understanding of the disposition of fentanyl following transdermal administration would facilitate the clinical use of TTS fentanyl to obtain analgesia in horses.

OBJECTIVES

To determine the pharmacokinetics of fentanyl following i.v. and TTS patch administration in healthy, mature horses and to evaluate the tolerance of horses to TTS fentanyl administration.

METHODS

The pharmacokinetics of fentanyl in serum were assessed following a single i.v. dose, a single TTS dose, and multiple TTS doses in 6 healthy horses. Physical examinations, haematology and serum biochemistry analyses during transdermal fentanyl application were then performed to determine tolerance of continuous fentanyl administration.

RESULTS

Fentanyl was very rapidly and completely absorbed following a single TTS dose. Mean serum fentanyl concentrations consistent with analgesia in other species were reached by 1 h and maintained until 32 h after patch application. Similar steady state serum concentrations were obtained when multiple doses of TTS fentanyl were administered every 48 or 72 h over 8 or 9 days, with less fluctuation in serum concentrations during the 48 h dosing interval. Three horses exhibited brief (< 12 h) episodes of increased body temperature; however, transdermal fentanyl administrations were not associated with other significant changes in haematology and biochemistry panels or physical examination findings.

CONCLUSIONS AND POTENTIAL RELEVANCE

Although the pharmacodynamics of fentanyl have not been investigated fully in horses, transdermally-administered fentanyl exhibited a favourable pharmacokinetic profile without clinically relevant side effects and may be a useful analgesic in equine patients.

Endogenous opiates and behavior: 2001

This paper is the twenty-fourth installment of the annual review of research concerning the opiate system. It summarizes papers published during 2001 that studied the behavioral effects of the opiate peptides and antagonists. The particular topics covered this year include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology(Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).

The use of transdermal fentanyl in the treatment of cancer pain

The management of pain is complex having to take into consideration patient specific characteristics. Drug therapy should be individualized and managed based on numerous factors. The opioid of first choice for the treatment of cancer pain is morphine, according to the European Association for Palliative Care (2000). Transdermally administered fentanyl is one alternative to oral morphine in the treatment of cancer pain. The transdermal systems are designed to deliver fentanyl at a constant rate for periods of 72 hours. Patches with a delivery rate of 25, 50, 75 and 100 ?g/h are available. Treatment with transdermal fentanyl is safe and acceptable to many cancer patients. Significantly more patients expressed a preference for transdermal fentanyl than for sustained release oral morphine. The global score of adverse effects was significantly lower in patients receiving transdermal fentanyl than in those receiving sustained release oral morphine. The transdermal fentanyl patch is as effective as oral opioids in relieving cancer related pain, with a safety and side effect profile equal to or better than that of oral opioids.