Long-term management of noncancer pain with transdermal therapeutic system-fentanyl

Management of chronic non-cancer pain: a framework

Aim: Since publication of the CDC 2016 Guideline, opioid-related mortality in the USA has doubled and a crisis has developed among the 15-20 million Americans with chronic, moderate-to-severe, noncancer pain. Our aim was to develop a comprehensive alternative approach to management of chronic pain. Methods: Analytic review of the clinical literature. Results: Published science provides a solid framework for the management of chronic non-cancer pain, detailed here, even as it leaves many knowledge gaps, which we fill with insights from clinical experience. Conclusion: There is a sufficient basis in science and in clinical experience to achieve adequate control of chronic pain in nearly all patients in a way that adequately balances benefits and potential harms.

Opioids and Chronic Pain: An Analytic Review of the Clinical Evidence

We conducted an analytic review of the clinical scientific literature bearing on the use of opioids for treatment of chronic non-cancer pain in the United States. There is substantial, albeit not definitive, scientific evidence of the effectiveness of opioids in treating pain and of high variability in opioid dose requirements and side effects. The estimated risk of death from opioid treatment involving doses above 100 MMED is ~0.25%/year. Multiple large studies refute the concept that short-term use of opioids to treat acute pain predisposes to development of opioid use disorder. The prevalence of opioid use disorder associated with prescription opioids is likely <3%. Morbidity, mortality, and financial costs of inadequate treatment of the 18 million Americans with moderate to severe chronic pain are high. Because of the absence of comparative effectiveness studies, there are no scientific grounds for considering alternative non-pharmacologic treatments as an adequate substitute for opioid therapy but these treatments might serve to augment opioid therapy, thereby reducing dosage. There are reasons to question the ostensible risks of co-prescription of opioids and benzodiazepines. As the causes of the opioid crisis have come into focus, it has become clear that the crisis resides predominantly in the streets and that efforts to curtail it by constraining opioid treatment in the clinic are unlikely to succeed.

Mindfulness-oriented recovery enhancement reduces opioid dose in primary care by strengthening autonomic regulation during meditation

The current opioid crisis was fueled by escalation of opioid dosing among patients with chronic pain. Yet, there are few evidence-based psychological interventions for opioid dose reduction among chronic pain patients treated with long-term opioid analgesics. Mindfulness-Oriented Recovery Enhancement (MORE), which was designed to target mechanisms underpinning chronic pain and opioid misuse, has shown promising results in 2 randomized clinical trials (RCTs) and could facilitate opioid sparing and tapering by bolstering self-regulation. Here we tested this hypothesis with secondary analyses of data from a Stage 2 RCT. Chronic pain patients (N = 95) on long-term opioid therapy were randomized to 8 weeks of MORE or a support group (SG) control delivered in primary care. Opioid dose was assessed with the Timeline Followback through 3-month follow-up. Heart rate variability (HRV) during mindfulness meditation was quantified as an indicator of self-regulatory capacity. Participants in MORE evidenced a greater decrease in opioid dosing (a 32% decrease) by follow-up than did the SG, F(2, 129.77) = 5.35, p = .006, d = 1.07. MORE was associated with a significantly greater increase in HRV during meditation than was the SG. Meditation-induced change in HRV partially mediated the effect of MORE on opioid dose reduction (p = .034). MORE may boost self-regulatory strength via mindfulness and thereby facilitate self-control over opioid use, leading to opioid dose reduction in people with chronic pain. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Gabapentin versus Transdermal Fentanyl Matrix for the Alleviation of Chronic Neuropathic Pain of Radicular Origin: A Randomized Blind Multicentered Parallel-Group Noninferiority Trial

A number of studies have been published proposing various approaches to the treatment of neuropathic pain; however, to our knowledge, no attempts have been made to compare gabapentin and fentanyl in patients with lumbar radiculopathy. We evaluated the relative efficacy and safety of fentanyl matrix and gabapentin for the treatment of chronic neuropathic pain of radicular origin. The study was designed as a randomized blind multicentered parallel-group noninferiority trial. A total of 108 patients with moderate-to-severe pain (≥4 intensity on an 11-point numeric rating scale) were randomly prescribed either fentanyl matrix or gabapentin over a period of 56 days. In the primary analysis, the noninferiority of fentanyl matrix treatment was evaluated in relation to the efficacy of gabapentin based on the pain intensity difference (PID) at 56 days after the first dose of the drugs. Secondary endpoints included pain relief, improvement in functional status (the Korean-Oswestry Disability Index (K-ODI)), improvement in depressive symptoms (Korean-Beck Depression Index (K-BDI)) between the 28th and 56th day, and adverse events (AEs). Analysis of the primary efficacy endpoint established the noninferiority of fentanyl matrix compared with gabapentin, with no statistically significant difference observed in the PID after 56 days for the two treatment groups. Similarly, analysis of pain relief revealed no significant differences between the groups on days 28 and 56. There was no difference in the K-ODI and K-BDI between the groups during the study period. The overall incidence of at least one AE was similar for fentanyl matrix (67.3%) and gabapentin (69.6%). The most commonly reported AEs for patients treated with fentanyl matrix and gabapentin included dizziness (30.8% vs. 44.6%, respectively), somnolence (26.9% vs. 35.7%), and constipation (15.4% vs. 17.9%). This study demonstrated that the analgesic effect of fentanyl matrix is noninferior in comparison with gabapentin and supports the use of fentanyl matrix as an effective and safe treatment for moderate-to-severe chronic neuropathic pain. This trial is registered with NCT01127100.

Chronic Pain and the Opioid Conundrum

Opioids prescribed for chronic cancer and noncancer pain have been embroiled in public policy debates as to effectiveness and potential for contributing to society's problem with misuse, addiction, and overdose mortality. The conundrum of opioid prescribing is to determine who will most likely benefit from opioids and how medical practitioners may safely provide chronic opioid therapy, while also identifying patients who are unlikely to benefit or could divert illicit pharmaceuticals into society. Risk assessment and monitoring are essential to meet the standard of care, as is compliance with federal controlled substances law as well as state regulations.

Fentanyl for neuropathic pain in adults

BACKGROUND

Opioid drugs, including fentanyl, are commonly used to treat neuropathic pain, and are considered effective by some professionals. Most reviews have examined all opioids together. This review sought evidence specifically for fentanyl, at any dose, and by any route of administration. Other opioids are considered in separate reviews.

OBJECTIVES

To assess the analgesic efficacy of fentanyl for chronic neuropathic pain in adults, and the adverse events associated with its use in clinical trials.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase from inception to June 2016, together with the reference lists of retrieved articles, and two online study registries.

SELECTION CRITERIA

We included randomised, double-blind studies of two weeks' duration or longer, comparing fentanyl (in any dose, administered by any route, and in any formulation) with placebo or another active treatment in chronic neuropathic pain.

DATA COLLECTION AND ANALYSIS

Two review authors independently searched for studies, extracted efficacy and adverse event data, and examined issues of study quality and potential bias. We did not carry out any pooled analyses. We assessed the quality of the evidence using GRADE.

MAIN RESULTS

Only one study met our inclusion criteria. Participants were men and women (mean age 67 years), with postherpetic neuralgia, complex regional pain syndrome, or chronic postoperative pain. They were experiencing inadequate relief from non-opioid analgesics, and had not previously taken opioids for their neuropathic pain. The study used an enriched enrolment randomised withdrawal design. It was adequately blinded, but we judged it at unclear risk of bias for other criteria.Transdermal fentanyl (one-day fentanyl patch) was titrated over 10 to 29 days to establish the maximum tolerated and effective dose (12.5 to 50 µg/h). Participants who achieved a prespecified good level of pain relief with a stable dose of fentanyl, without excessive use of rescue medication or intolerable adverse events ('responders'), were randomised to continue with fentanyl or switch to placebo for 12 weeks, under double-blind conditions. Our prespecified primary outcomes were not appropriate for this study design, but the measures reported do give an indication of the efficacy of fentanyl in this condition.In the titration phase, 1 in 3 participants withdrew because of adverse events or inadequate pain relief, and almost 90% experienced adverse events. Of 258 participants who underwent open-label titration, 163 were 'responders' and entered the randomised withdrawal phase. The number of participants completing the study (and therefore continuing on treatment) without an increase of pain by more than 15/100 was 47/84 (56%) with fentanyl and 28/79 (35%) with placebo. Because only 63% responded sufficiently to enter the randomised withdrawal phase, this implies that only a maximum of 35% of participants entering the study would have had useful pain relief and tolerability with transdermal fentanyl, compared with 22% with placebo. Almost 60% of participants taking fentanyl were 'satisfied' and 'very satisfied' with their treatment at the end of the study, compared with about 40% with placebo. This outcome approximates to our primary outcome of moderate benefit using the Patient Global Impression of Change scale, but the group was enriched for responders and the method of analysis was not clear. The most common adverse events were constipation, nausea, somnolence, and dizziness.There was no information about other types of neuropathic pain, other routes of administration, or comparisons with other treatments.We downgraded the quality of the evidence to very low because there was only one study, with few participants and events, and there was no information about how data from people who withdrew were analysed.

AUTHORS' CONCLUSIONS

There is insufficient evidence to support or refute the suggestion that fentanyl works in any neuropathic pain condition.

Opioids for chronic noncancer pain: To prescribe or not to prescribe-What is the question?

The recent American Academy of Neurology position paper by Franklin, "Opioids for chronic noncancer pain," suggests that the benefits of opioid treatment are very likely to be substantially outweighed by the risks and recommends avoidance of doses above 80-120 mg/day morphine equivalent. However, close reading of the primary literature supports a different conclusion: opioids have been shown in randomized controlled trials (RCTs) to be highly effective in the treatment of chronic nonmalignant pain; long-term follow-up studies have shown that this effectiveness can be maintained; and effectiveness has been limited in many clinical trials by failure to take into account high variability in dose requirements, failure to adequately treat depression, and use of suboptimal outcome measures. Frequency of side effects in many RCTs has been inflated by overly rapid dose titration and failure to appreciate the high interindividual variability in side effect profiles. The recent marked increase in incidence of opioid overdose is of grave concern, but there is good reason to believe that it has been somewhat exaggerated. Potential causes of overdose include inadequately treated depression; inadequately treated pain, particularly when compounded by hopelessness; inadvertent overdose; concurrent use of alcohol; and insufficient practitioner expertise. Effective treatment of pain can enable large numbers of patients to lead productive lives and improve quality of life. Effective alleviation of suffering associated with pain falls squarely within the physician's professional obligation. Existing scientific studies provide the basis for many improvements in pain management that can increase effectiveness and reduce risk. Many potentially useful areas of further research can be identified.

Misuse of fentanyl transdermal patch mixed with acute coronary syndrome

Fentanyl transdermal patches have long been used in the palliative care of patients with chronic pain with a favorable safety profile. However, intoxications secondary to intentional and unintentional misuse have been widely reported. In this study, we report an otherwise healthy woman presented to emergency department who used three patches of fentanyl to alleviate her knee pain and with a picture mimicking acute coronary syndrome.

Long-term opioid treatment of chronic nonmalignant pain: unproven efficacy and neglected safety?

BACKGROUND

For the past 30 years, opioids have been used to treat chronic nonmalignant pain. This study tests the following hypotheses: (1) there is no strong evidence-based foundation for the conclusion that long-term opioid treatment of chronic nonmalignant pain is effective; and (2) the main problem associated with the safety of such treatment - assessment of the risk of addiction - has been neglected.

METHODS

Scientometric analysis of the articles representing clinical research in this area was performed to assess (1) the quality of presented evidence (type of study); and (2) the duration of the treatment phase. The sufficiency of representation of addiction was assessed by counting the number of articles that represent (1) editorials; (2) articles in the top specialty journals; and (3) articles with titles clearly indicating that the addiction-related safety is involved (topic-in-title articles).

RESULTS

Not a single randomized controlled trial with opioid treatment lasting >3 months was found. All studies with a duration of opioid treatment ≥6 months (n = 16) were conducted without a proper control group. Such studies cannot provide the consistent good-quality evidence necessary for a strong clinical recommendation. There were profound differences in the number of addiction articles related specifically to chronic nonmalignant pain patients and to opioid addiction in general. An inadequate number of chronic pain-related publications were observed with all three types of counted articles: editorials, articles in the top specialty journals, and topic-in-title articles.

CONCLUSION

There is no strong evidence-based foundation for the conclusion that long-term opioid treatment of chronic nonmalignant pain is effective. The above identified signs indicating neglect of addiction associated with the opioid treatment of chronic nonmalignant pain were present.

The efficacy of transdermal fentanyl for pain relief after endoscopic submucosal dissection: a prospective, randomised controlled trial

OBJECTIVE

Epigastric pain management following endoscopic submucosal dissection is an important consideration. This study aimed to investigate the utility and safety of fentanyl patches for pain relief after the procedure.

METHODS

Patients who were scheduled to undergo endoscopic submucosal dissection were prospectively randomised to either a transdermal fentanyl patch group or a placebo control group. An additional pethidine was intravenously administered when pain developed and a numerical rating scale was used to evaluate both pre- and post-procedural pain.

RESULTS

One hundred and ten patients were randomly assigned to receive either a 12 mcg/h fentanyl patch or a control patch on the night before the procedure. The fentanyl patch group had significantly lower pain scores immediately following the procedure (mean, 5.17 vs. 4.26, p=0.030). Maximal pain scores during the first 24 h (5.43 vs. 4.46, p=0.038) and pain scores on the day after the procedure (2.98 vs. 1.20, p<0.001) were also lower in the fentanyl patch group. In addition, the fentanyl patch group required a significantly lower dose of pethidine for pain management (24.54 vs. 11.25, p=0.004).

CONCLUSIONS

The application of a transdermal fentanyl patch is an effective, convenient, and safe method to control epigastric pain after endoscopic submucosal dissection.

Molecular and cellular mechanisms of the age-dependency of opioid analgesia and tolerance

The age-dependency of opioid analgesia and tolerance has been noticed in both clinical observation and laboratory studies. Evidence shows that many molecular and cellular events that play essential roles in opioid analgesia and tolerance are actually age-dependent. For example, the expression and functions of endogenous opioid peptides, multiple types of opioid receptors, G protein subunits that couple to opioid receptors, and regulators of G protein signaling (RGS proteins) change with development and age. Other signaling systems that are critical to opioid tolerance development, such as N-methyl-D-aspartic acid (NMDA) receptors, also undergo age-related changes. It is plausible that the age-dependent expression and functions of molecules within and related to the opioid signaling pathways, as well as age-dependent cellular activity such as agonist-induced opioid receptor internalization and desensitization, eventually lead to significant age-dependent changes in opioid analgesia and tolerance development.

Adherence and long-term effect of oxycodone/paracetamol in chronic noncancer pain: a retrospective study

INTRODUCTION

Long-term administration of opiates in patients with chronic noncancer pain (CNCP) is subject to debate due to insufficient clinical evidence to support efficacy and tolerability.

METHODS

This retrospective analysis used hospital records to investigate the effects of low doses of the combination of oxycodone/paracetamol on CNCP in an outpatient clinic setting to verify adherence to therapy and long-term efficacy. All patients receiving therapy for CNCP were examined between May and September 2010 and information was collected on medication, duration of therapy, and static and dynamic pain measured using numeric rating scales (NRS) from relevant charts.

RESULTS

Two hundred and thirty-one patients (157 men, 68%) with a mean (± SD) age of 66.4±15.5 years were analyzed. Pain indexes at baseline revealed a mean (± SD) static NRS (sNRS) of 3.5±1.77 and a mean dynamic NRS (dNRS) of 7.24±1.33. At last follow-up, mean (± SD) pain reductions versus baseline were 1.58±1.42 for sNRS and 3.04±1.43 for dNRS (P<0.0001 for both). Regarding the duration of therapy, 54 patients (23.4%) were treated for <4 months, and 177 patients (76.6%) for 4 months up to 23 months. Pain reduction was significant in all groups (P<0.0001) but was greatest in patients who had been receiving therapy for ≥4 months. Improvements in pain relief were not associated with an increase in daily dose, which remained stable or decreased slightly over time.

DISCUSSION

The results of this study support the hypothesis that an opiate-based combination at low doses improves tolerability and adherence and results in patients obtaining long-term efficacy. Larger studies of the use of opiates in this setting and clinical monitoring on the regional and national level may convince clinicians to view opiates as efficacious analgesics and not as dangerous substances of abuse.

Long-term dosing, safety, and tolerability of fentanyl buccal tablet in the management of noncancer-related breakthrough pain in opioid-tolerant patients

OBJECTIVE

To evaluate the long-term dosing, safety, and tolerability of fentanyl buccal tablet (FBT) in a large cohort of opioid-tolerant patients with chronic noncancer pain and breakthrough pain (BTP).

DESIGN

Combined analysis of three double-blind, placebo-controlled, and two open-label studies.

RESULTS

Of 1160 patients who received ≥1 dose of FBT, 83% achieved a successful dose, ranging from 100 to 800 μg, mostly at 600 or 800 μg. Not all of the patients included in this analysis were enrolled in long-term studies and 156 (13%) patients were still receiving ongoing treatment when their study site closed. Median treatment duration was 106.0 days. The mean FBT dose in the post-titration population (n = 946) increased from 2108 to 3132 μg/day, with ≥1 FBT dose increase in 27% of patients; most dose increases occurred during the first 6 months. The FBT daily dose as a proportion of the daily opioid dose remained fairly stable (59-65%) throughout the treatment period. Overall, 925 (80%) enrolled patients had ≥1 adverse event (AE). The most frequent AEs were nausea (21% of patients), vomiting (11%), dizziness (10%), and headache (10%). Common AEs generally occurred within 7 days of starting treatment and lasted for ≤2 days. Serious AEs occurred in 136 (12%) patients and included six deaths (none related to FBT) and 11 instances of opioid overdose (all with satisfactory resolution). AE-related discontinuations occurred in 163 (14%) patients and were similar to the common AEs.

CONCLUSIONS

Despite the limitations, including the controlled clinical setting, this pooled analysis of several clinical studies provides valuable information for the long-term management of BTP with FBT. Patients require regular evaluation and, when necessary, adjustment of opioid medications to maintain adequate pain control. FBT was generally safe and well tolerated in this setting.

Evaluation of efficacy and safety of fentanyl transdermal patch (Durogesic D-TRANS) in chronic pain

PURPOSE

Opioids are used in controlling several types of pain. This study was designed to evaluate the efficacy and safety of the fentanyl transdermal patch-type system (Durogesic® D-TRANS).

METHODS

Patients who complained of chronic moderate to severe pain were enrolled. Administration dosages of fentanyl patch started from 12.5 μg/h and could be increased by 12.5 μg/h or 25 μg/h, if the average pain score of 4 or higher occurred within 72 h. The total administration period was 12 weeks. The type, location, characteristics, and duration of pain were evaluated. Also, on day 0, weeks of 4, 8, and 12, the physician's assessment of pain intensity, the patient's assessment of pain intensity, the assessment of impact of pain on functions, and the assessment of the impact of pain on sleep were assessed. In addition, side effects were evaluated during the study duration.

RESULTS

A total of 65 cases were enrolled, and the final evaluated cases were 41. Before treatment, the average physician's assessment of pain intensity was 6.70 ± 1.41, and the average patient's assessment of pain intensity was 7.02 ± 1.63. In the final visit, the average physician's assessment of pain intensity was 2.58 ± 1.72, and the average patient's assessment of pain intensity was 2.86 ± 1.78.

CONCLUSIONS

This prospective study shows that the fentanyl patch is effective in alleviating moderate to severe chronic noncancer pain including neuropathic pain down to mild pain. Therefore, the fentanyl patch should be considered before other invasive intervention procedures in chronic moderate to severe noncancer pain.

Long-term opioid management for chronic noncancer pain

BACKGROUND

Opioid therapy for chronic noncancer pain (CNCP) is controversial due to concerns regarding long-term effectiveness and safety, particularly the risk of tolerance, dependence, or abuse.

OBJECTIVES

To assess safety, efficacy, and effectiveness of opioids taken long-term for CNCP.

SEARCH STRATEGY

We searched 10 bibliographic databases up to May 2009.

SELECTION CRITERIA

We searched for studies that: collected efficacy data on participants after at least 6 months of treatment; were full-text articles; did not include redundant data; were prospective; enrolled at least 10 participants; reported data of participants who had CNCP. Randomized controlled trials (RCTs) and pre-post case-series studies were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted safety and effectiveness data and settled discrepancies by consensus. We used random-effects meta-analysis' to summarize data where appropriate, used the I(2) statistic to quantify heterogeneity, and, where appropriate, explored heterogeneity using meta-regression. Several sensitivity analyses were performed to test the robustness of the results.

MAIN RESULTS

We reviewed 26 studies with 27 treatment groups that enrolled a total of 4893 participants. Twenty five of the studies were case series or uncontrolled long-term trial continuations, the other was an RCT comparing two opioids. Opioids were administered orally (number of study treatments groups [abbreviated as "k"] = 12, n = 3040), transdermally (k = 5, n = 1628), or intrathecally (k = 10, n = 231). Many participants discontinued due to adverse effects (oral: 22.9% [95% confidence interval (CI): 15.3% to 32.8%]; transdermal: 12.1% [95% CI: 4.9% to 27.0%]; intrathecal: 8.9% [95% CI: 4.0% to 26.1%]); or insufficient pain relief (oral: 10.3% [95% CI: 7.6% to 13.9%]; intrathecal: 7.6% [95% CI: 3.7% to 14.8%]; transdermal: 5.8% [95% CI: 4.2% to 7.9%]). Signs of opioid addiction were reported in 0.27% of participants in the studies that reported that outcome. All three modes of administration were associated with clinically significant reductions in pain, but the amount of pain relief varied among studies. Findings regarding quality of life and functional status were inconclusive due to an insufficient quantity of evidence for oral administration studies and inconclusive statistical findings for transdermal and intrathecal administration studies.

AUTHORS' CONCLUSIONS

Many patients discontinue long-term opioid therapy (especially oral opioids) due to adverse events or insufficient pain relief; however, weak evidence suggests that patients who are able to continue opioids long-term experience clinically significant pain relief. Whether quality of life or functioning improves is inconclusive. Many minor adverse events (like nausea and headache) occurred, but serious adverse events, including iatrogenic opioid addiction, were rare.

Impact of opioid rescue medication for breakthrough pain on the efficacy and tolerability of long-acting opioids in patients with chronic non-malignant pain

Background

There is little evidence that short-acting opioids as rescue medication for breakthrough pain is an optimal long-term treatment strategy in chronic non-malignant pain. We compared clinical studies of long-acting opioids that allowed short-acting opioid rescue medication with those that did not, to determine the impact of opioid rescue medication use on the analgesic efficacy and tolerability of chronic opioid therapy in patients with chronic non-malignant pain.

Methods

We searched MEDLINE (1950 to July 2006) and EMBASE (1974 to July 2006) using terms for chronic non-malignant pain and long-acting opioids. Independent review of the search results identified 48 studies that met the study selection criteria. The effect of opioid rescue medication on analgesic efficacy and the incidence of common opioid-related side-effects were analysed using meta-regression.

Results

After adjusting for potentially confounding variables (study design and type of opioid), the difference in analgesic efficacy between the ‘rescue’ and the ‘no rescue’ studies was not significant, with regression coefficients close to 0 and 95% confidence intervals that excluded an effect of more than 18 points on a 0–100 scale in each case. There was also no significant difference between the ‘rescue’ and the ‘no rescue’ studies for the incidence of nausea, constipation, or somnolence in both the unadjusted and the adjusted analyses.

Conclusions

We found no evidence that rescue medication with short-acting opioids for breakthrough pain affects analgesic efficacy of long-acting opioids or the incidence of common opioid-related side-effects among chronic non-malignant pain patients.

Pain therapy

Cancer-related pain is a major issue of healthcare systems worldwide. The reported incidence, considering all stages of the disease, is 51%, which can increase to 74% in the advanced and terminal stages. For advanced cancer, pain is moderate to severe in about 40-50% and very severe or excruciating in 25-30% of cases. Pain is both a sensation and an emotional experience. Pain is always subjective; and may be affected by emotional, social and spiritual components thus it has been defined as "total pain". From a pathophysiological point of view, pain can be classified as nociceptive (somatic and visceral), neuropathic (central, peripheral, sympathetic) idiopathic or psychogenic. A proper pain assessment is fundamental for an effective and individualised treatment. In 1986 the World Health Organisation (WHO) published analgesic guidelines for the treatment of cancer pain based on a three-step ladder and practical recommendations. These guidelines serve as an algorithm for a sequential pharmacological approach to treatment according to the intensity of pain as reported by the patient. The WHO analgesic ladder remains the clinical model for pain therapy. Its clinical application should be employed only after a complete and comprehensive assessment and evaluation based on the needs of each patient. When applying the WHO guidelines, up to 90% of patients can find relief regardless of the settings of care, social and/or cultural environment. This is the standard treatment on a type C basis. Only when such an approach is ineffective are interventions such as spinal administration of opioid analgesics or neuroinvasive procedures recommended.

Cancer pain and analgesia

Pain ranges in prevalence from 14-100% among cancer patients and occurs in 50-70% of those in active treatment. Cancer pain may result from direct invasion of tumor into nerves, bones, soft tissue, ligaments, and fascia, and may induce visceral pain through distension and obstruction. Cancer pain is multifaceted. Clinicians may describe cancer pain as acute, chronic, nociceptive (somatic), visceral, or neuropathic. Despite implementation of the WHO guidelines, reports of undertreatment of cancer pain persist in various clinical settings and in spite of decades of work to reduce unnecessary discomfort. Substantial obstacles to adequate pain relief with opioids include specific concerns of patients themselves, their family members, physicians, nurses, and the healthcare system. The WHO analgesic ladder serves as the mainstay of treatment for the relief of cancer pain in concert with tumoricidal, surgical, interventional, radiotherapeutic, psychological, and rehabilitative modalities. This multidimensional approach offers the greatest potential for maximizing analgesia and minimizing adverse effects. Primary therapies are directed at the source of the cancer pain and may enhance a patient's function, longevity, and comfort. Adjuvant therapies include nonopioids that confer analgesic effects in certain medical conditions but primarily treat conditions that do not involve pain. Nonopioid medications (over-the-counter agents) are useful in the management of mild to moderate pain, and their continuation through step 3 of the WHO ladder is an option after weighing a drug's risks and benefits in individual patients. Symptomatic treatment of severe cancer pain should begin with an opioid, regardless of the mechanism of the pain. They are very effective analgesics, titrate easily, and offer a favorable risk/benefit ratio. Cancer pain remains inadequately controlled despite the diagnostic and therapeutic means of ensuring that patients feel comfortable during their illness. Therefore, all practitioners need to make control of cancer pain a professional duty, even if they can only use the most basic and least expensive analgesic medications, such as morphine, codeine, and acetaminophen, to reduce human suffering.

Efficacy of opioids for chronic pain: a review of the evidence

Opioid therapy for chronic pain has been popularized over the past few decades, and a concern has arisen that the analgesic efficacy of opioids is not always maintained over prolonged courses of treatment despite dose escalation and stable pain. Considering the potentially serious adverse effects of opioids, the idea that pain relief could diminish over time may have a significant impact on the decision to embark on this therapy, especially in vulnerable individuals. Possible loss of analgesic efficacy is especially concerning, considering that dependence may make it hard to withdraw opioid therapy even in the face of poor analgesia. This article first reviews the evidence on opioid efficacy when used for the treatment of chronic pain, and concludes that existing evidence suggests that analgesic efficacy, although initially good, is not always sustained during continuous and long-term opioid therapy (months to years). The theoretical basis for loss of analgesic efficacy over time is then examined. Mechanisms for loss of analgesic efficacy proposed are pharmacologic tolerance, opioid-induced hyperalgesia, subtle and intermittent withdrawal, and a number of psychologic factors including loss of the placebo component.

What percentage of chronic nonmalignant pain patients exposed to chronic opioid analgesic therapy develop abuse/addiction and/or aberrant drug-related behaviors? A structured evidence-based review

DESIGN

This is a structured evidence-based review of all available studies on the development of abuse/addiction and aberrant drug-related behaviors (ADRBs) in chronic pain patients (CPPs) with nonmalignant pain on exposure to chronic opioid analgesic therapy (COAT).

OBJECTIVES

To determine what percentage of CPPs develop abuse/addiction and/or ADRBs on COAT exposure.

METHOD

Computer and manual literature searches yielded 79 references that addressed this area of study. Twelve of the studies were excluded from detailed review based on exclusion criteria important to this area. Sixty-seven studies were reviewed in detail and sorted according to whether they reported percentages of CPPs developing abuse/addiction or developing ADRBs, or percentages diagnosed with alcohol/illicit drug use as determined by urine toxicology. Study characteristics were abstracted into tabular form, and each report was characterized according to the type of study it represented based on the Agency for Health Care Policy and Research Guidelines. Each study was independently evaluated by two raters according to 12 quality criteria and a quality score calculated. Studies were not utilized in the calculations unless their quality score (utilizing both raters) was greater than 65%. Within each of the above study groupings, the total number of CPPs exposed to opioids on COAT treatment was calculated. Similarly, the total number of CPPs in each grouping demonstrating abuse/addiction, ADRBs, or alcohol/illicit drug use was also calculated. Finally, a percentage for each of these behaviors was calculated in each grouping, utilizing the total number of CPPs exposed to opioids in each grouping.

RESULTS

All 67 reports had quality scores greater than 65%. For the abuse/addiction grouping there were 24 studies with 2,507 CPPs exposed for a calculated abuse/addiction rate of 3.27%. Within this grouping for those studies that had preselected CPPs for COAT exposure for no previous or current history of abuse/addiction, the percentage of abuse/addiction was calculated at 0.19%. For the ADRB grouping, there were 17 studies with 2,466 CPPs exposed and a calculated ADRB rate of 11.5%. Within this grouping for preselected CPPs (as above), the percentage of ADRBs was calculated at 0.59%. In the urine toxicology grouping, there were five studies (15,442 CPPs exposed). Here, 20.4% of the CPPs had no prescribed opioid in urine and/or a nonprescribed opioid in urine. For five studies (1,965 CPPs exposed), illicit drugs were found in 14.5%.

CONCLUSION

The results of this evidence-based structured review indicate that COAT exposure will lead to abuse/addiction in a small percentage of CPPs, but a larger percentage will demonstrate ADRBs and illicit drug use. These percentages appear to be much less if CPPs are preselected for the absence of a current or past history of alcohol/illicit drug use or abuse/addiction.

An update on the role of opioids in the management of chronic pain of nonmalignant origin

PURPOSE OF REVIEW

To summarize and reflect over primarily recent epidemiological and randomized controlled trials in opioid-treated chronic nonmalignant pain patients, focusing on effects, side effects, risks and long-term consequences of the treatment.

RECENT FINDINGS

In the western world opioids are increasingly being used for long-term treatment of chronic nonmalignant pain. While the long-term benefits of opioids regarding pain relief, functional capacity and health-related quality of life still remain to be proven, studies are emerging that describe serious long-term consequences such as addiction, opioid-induced hyperalgesia, cognitive disorders, and suppression of the immune and reproductive systems.

SUMMARY

Much more research is needed concerning long-time effects and consequences of opioid therapy in chronic nonmalignant pain patients; however, some clear warning signals have been sent out within recent years.

Long-term opioid therapy for chronic noncancer pain: a systematic review and meta-analysis of efficacy and safety

Opioid therapy for chronic noncancer pain (CNCP) is controversial due to concerns regarding long-term efficacy and adverse events (including addiction). We systematically reviewed the clinical evidence on patients treated with opioids for CNCP for at least six months. Of 115 studies identified by our search of eleven databases (through April 7, 2007), 17 studies (patients [n]=3,079) met inclusion criteria. Studies evaluated oral (studies [k]=7; n=1,504), transdermal (k=3; n=1, 993), and/or intrathecal (k=8; n=177) opioids. Many patients withdrew from the clinical trials due to adverse effects (oral: 32.5% [95% confidence interval (CI), 26.1%-39.6%]; intrathecal: 6.3% [95% CI, 2.9%-13.1%]; transdermal: 17.5% [95% CI, 6.5%-39.0%]), or due to insufficient pain relief (oral: 11.9% [95% CI, 7.8%-17.7%]; intrathecal: 10.5% [95% CI, 3.5%-27.4%]; transdermal: 5.8% [95% CI, 4.2%-7.3%]). Signs of opioid addiction were reported in only 0.05% (1/2,042) of patients and abuse in only 0.43% (3/685). There was an insufficient amount of data on transdermal opioids to quantify pain relief. For patients able to remain on oral or intrathecal opioids for at least six months, pain scores were reduced long-term (oral: standardized mean difference [SMD] 1.99, 95% CI, 1.17-2.80; intrathecal: SMD 1.33, 95% CI, 0.97-1.69). We conclude that many patients discontinue long-term opioid therapy due to adverse events or insufficient pain relief; however, weak evidence suggests that oral and intrathecal opioids reduce pain long-term in the relatively small proportion of individuals with CNCP who continue treatment.

Evidence-based clinical practice guidelines for interdisciplinary rehabilitation of chronic nonmalignant pain syndrome patients

This is an update to evidence-based practice guidelines for chronic nonmalignant pain syndrome patients first published in 1995 and revised in 1999. The current guidelines recommend interdisciplinary-focused rehabilitation, which is goal-directed and time-limited. Emphasis is placed on educating patients in active self-management techniques that stress maximizing function. Integrated treatment involving medical, psychological/behavioral, physical/occupational therapy, and disability/vocational interventions are recommended on an outpatient basis whenever clinically possible. Patient selection criteria are delineated. Updated references providing evidence-based support for the recommendations are provided, including the use of opioids and sedative-hypnotic medications, injection and block procedures, acupuncture, implantable spinal infusion and stimulation devices, and other invasive spinal surgery procedures such as intradiscal electrothermal therapy. Guideline integration and early detection and intervention with chronic pain syndrome patients are encouraged.

Transdermal treatment options for neurological disorders: impact on the elderly

As people grow old, their need for medications increases dramatically because of the higher incidence of chronic pain, diabetes mellitus, cardiovascular and neurological diseases in the elderly population. Furthermore, the elderly require special consideration with respect to drug delivery, drug interactions and adherence. In particular, patients with chronic neurological diseases often require multiple administration of drugs during the day to maintain constant plasma medication levels, which in turn increases the likelihood of poor adherence. Consequently, several attempts have been made to develop pharmacological preparations that can achieve a constant rate of drug delivery. For example, transdermal lisuride and apomorphine have been shown to reduce motor fluctuations and duration of 'off' periods in advanced Parkinson's disease, while rotigotine allows significant down-titration of levodopa without severe adverse effects. Thus, parkinsonian patients with long-term levodopa syndrome or motor disorders during sleep could benefit from use of transdermal lisuride and apomorphine. Moreover, transdermal dopaminergic drugs, particularly rotigotine, seem the ideal treatment for patients experiencing restless legs syndrome or periodic limb movement disorder during sleep, disorders that are quite common in elderly people or in association with neurodegenerative diseases. Unlike dopaminergic drugs, transdermal treatments for the management of cognitive and behavioural dysfunction in patients with Parkinson's disease and Alzheimer's disease have inconsistent effects and no clearly established role. Nevertheless, because of their favourable pharmacological profile and bioavailability, the cholinesterase inhibitors tacrine and rivastigmine are expected to show at least the same benefits as oral formulations of these drugs, but with fewer severe adverse effects. Transdermal delivery systems play an important role in the management of neuropathic pain. The transdermal lidocaine (lignocaine) patch is recommended as first-line therapy for the treatment of postherpetic neuralgia. Furthermore, in patients with severe persistent pain, transdermal delivery systems using the opioids fentanyl and buprenorphine are able to achieve satisfactory analgesia with good tolerability, comparable to the benefits seen with oral formulations. Transdermal administration is the ideal therapeutic approach for chronic neurological disorders in elderly people because it provides sustained therapeutic plasma levels of drugs, is simple to use, and may reduce systemic adverse effects. Several transdermal delivery systems are currently under investigation for the treatment of Parkinson's disease, Alzheimer's disease and neuropathic pain. Although most transdermal delivery systems treatments cannot be considered as first-line therapy at present, some of them provide clear advantages compared with other routes of administration and may become the preferred treatment in selected patients. In general, however, most transdermal treatments still require long-term evaluation in large patient groups in order to optimise dosages and evaluate the actual incidence of local and systemic adverse effects.

Long-term management of chronic pain with transdermal buprenorphine: a multicenter, open-label, follow-up study in patients from three short-term clinical trials

BACKGROUND

Transdermal buprenorphine is available in Europe for the treatment of moderate to severe chronic pain. It has been evaluated at doses of 35, 52.5, and 70 microg/h for the management of moderate to severe chronic cancer and noncancer pain in 3 randomized, double-blind, placebo-controlled trials, each of limited duration (approximately 14 days each). Long-term data are essential to determining the performance of an analgesic in the management of chronic pain.

OBJECTIVE

The purpose of this follow-up study was to obtain data on the efficacy and tolerability of long-term treatment with transdermal buprenorphine in cancer and noncancer patients with chronic persistent pain of moderate to severe intensity.

METHODS

This was an open-label, uncontrolled, follow-up study in patients from the 3 previous clinical trials who elected to continue treatment with transdermal buprenorphine 35 microg/h and sublingual buprenorphine tablets (0.2 mg) as needed for breakthrough pain. The patch was to be changed every 72 hours throughout the patient's course of pain therapy. At visits every 2 weeks for the first 4 weeks and every 4 weeks for the remainder of study participation, patients evaluated their pain relief retrospectively on a 4-point verbal rating scale. They also rated the ease of patch handling using a 3-point verbal rating scale. Patterns of dose escalation and dose stability were monitored over time. Adherence to therapy was determined based on the number of patients who complied with the dosing schedule. Adverse events were documented by type, intensity, location (systemic or local), and relationship to study medication.

RESULTS

Two hundred thirty-nine patients were included in this follow-up study (120 women, 119 men; 100% white; mean [SD] age, 58 [11.3] years; mean weight, 70.8 [14.7] kg). One hundred thirty-four had cancer-related pain and 105 had pain of noncancerous origin. The mean duration of participation was 7.5 months, and 37 (15.5%) patients participated for >12 months. Maximum study participation was 3.4 years in cancer patients and 5.7 years in noncancer patients. One hundred eighty-eight (78.7%) patients were considered adherent to therapy. The majority (65.9%) of patients managed their pain with the patchalone or took no more than 1 additional sublingual tablet daily for breakthrough pain. At least satisfactory pain relief was reported by 215 (90.0%) patients, and the buprenorphine patch was generally well tolerated. The most common systemic adverse drug reactions were nausea (9.2%), dizziness (4.6%), vomiting (4.2%), constipation (3.8%), and tiredness (2.9%), whereas the most common local adverse drug reactions were erythema (12.1%), pruritus (10.5%), and exanthema (8.8%).

CONCLUSION

Transdermal buprenorphine was generally well tolerated and effective for the long-term treatment of chronic cancer or noncancer pain in these patients who had previously received buprenorphine in 3 short-term clinical trials.

Patterns of Dosage changes with transdermal buprenorphine and transdermal fentanyl for the treatment of noncancer and cancer pain: A retrospective data analysis in Germany

BACKGROUND

Previous studies have suggested that buprenorphine may have a low association with tolerance development compared with other strong opioids. In a previous study by our group, mean cohort and intraindividual dosage increases over an entire course of treatment and on a per-day basis were significantly lower with transdermal (TD) buprenorphine than with TD fentanyl. However, no information concerning the relationship between qualitative and quantitative dose changes is available.

OBJECTIVE

The aim of this study was to compare TD buprenorphine and TD fentanyl with respect to dosage increases, dosage stability, and the nature of dosage changes.

METHODS

This retrospective analysis used data from the IMS Disease Analyzer-Mediplus database, which contains patient-related data documented by 400 medical practices in Germany. Data from patients with noncancer or cancer pain treated with TD buprenorphine or TD fentanyl for at least 3 months between May 2002 and April 2005 were analyzed. Daily dosages were directly determined from the prescribed patch strength, taking into account the possibility of multiple patches applied simultaneously. To determine dosage stability, patients were classified based on the type of dosage change (stable, increase, alternating, or decrease) of the prescribed dosages. From the prescribed daily dosages, mean percentage increases were calculated on a per-patient basis for the entire treatment period and per day, and these were assessed in relation to the type of dosage change.

RESULTS

In total, 631 patients with noncancer pain and 605 patients with cancer pain were included in the analysis (782 women, 454 men; mean age, 76.3 years [range, 29-100 years]). Treatment indications included osteoarthritis, low back pain, osteoporosis (noncancer groups), and neoplasm (cancer groups). Patients had similar analgesic premedication requirements based on steps 1 to 3 of the World Health Organization analgesic ladder. Comedication requirements for breakthrough pain were also similar between the TD buprenorphine and TD fentanyl groups. The mean percentage increases per day were 0.10% (TD buprenorphine) and 0.25% (TD fentanyl) in the noncancer groups and 0.19% (TD buprenorphine) and 0.47% (TD fentanyl) in the cancer groups (both, P < 0.05). A significantly larger proportion of patients receiving TD buprenorphine had stable dosages over the entire treatment period compared with patients receiving TD fentanyl (noncancer groups: 56.9% vs 41.6%; cancer groups: 50.0% vs 26.2% [both, P < 0.05]). Compared with TD buprenorphine, the proportion of patients with alternating dosage changes was significantly greater in patients receiving TD fentanyl (noncancer groups: 22.7% vs 13.1%; cancer groups: 30.6% vs 11.8% [both, P < 0.05]).

CONCLUSIONS

In this retrospective data analysis, compared with TD buprenorphine, the increase in mean daily dosage was significantly greater in patients treated with TD fentanyl. Also, compared with TD buprenorphine, alternating dosage changes were seen in a significantly greater proportion of patients receiving TD fentanyl. On the other hand, a significantly greater proportion of patients treated with TD buprenorphine had stable dosages over their entire treatment periods.

Impact of long-term use of opioids on quality of life in patients with chronic, non-malignant pain

OBJECTIVE

The use of opioids in the management of non-malignant pain remains controversial. For many physicians, pain relief stemming from opioid use is not enough unless there is also a noticeable change in quality of life (QoL) and patient functioning. The impact of long-term opioid treatment on patients' QoL has been investigated in a limited number of trials, and these studies differ considerably with respect to their design and principal findings. This systematic review presents the results of these studies.

DESIGN AND METHODS

MEDLINE (1966 to November/December 2004), EMBASE (1974 to November/December 2004), the Oxford Pain Relief Database (Bandolier; 1954-1994) and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched for relevant papers by combining search terms for function with terms for opioid analgesia, non-malignant and pain. Studies were eligible for inclusion if they met all of the pre-defined criteria specifying study design, population, intervention and outcome measures.

RESULTS

Eleven studies evaluated long-term treatment with opioids in patients with chronic, non-malignant pain and assessed QoL (N = 2877). Six studies were randomised trials and the remaining five were observational studies. In general, the former had higher Jadad rating scores for the quality of the paper than the latter. Of the four randomised studies in which baseline QoL was reported, three showed an improvement in QoL. Similarly, of the five observational studies, a significant improvement in QoL was reported in four.

CONCLUSIONS

There is both moderate/high- and low-quality evidence suggesting that long-term treatment with opioids can lead to significant improvements in functional outcomes, including QoL, in patients with chronic, non-malignant pain. However, further methodologically rigorous investigations are required to confirm the long-term QoL benefit of opioid treatment in these patients, and to elucidate the effect of physical tolerance, withdrawal and addiction, which are all associated with long-term use of opioids, on patients' functional status.

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.

Age-dependent opioid escalation in chronic pain patients

Rapid opioid dose escalation, possibly caused by tolerance, has been observed in some patients on daily opioid therapy, although clinically identifiable characteristics of these patients are unknown. In this retrospective chart review of 206 patients, we examined whether the age of the patient was related to opioid escalation. Initial starting doses of long-acting opioids were similar in younger patients (< or =50 yr; 49 +/- 3 mg/d oral morphine-equivalent dose) versus older patients (> or =60 yr; 42 +/- 3 mg/d). Younger patients reached a maximum dose of 452 +/- 63 mg/d over 15.0 +/- 1.3 mo, whereas older patients achieved a maximum dose of 211 +/- 23 mg/d over 14.4 +/- 1.5 mo (P < 0.0001). At the last clinic visit, younger-patient dosing averaged 365 +/- 61 mg/d, with older patients averaging 168 +/- 18 mg/d (P < 0.0001). Only older patients demonstrated a reduction in visual analog scale scores from start of opioid therapy until discharge from the clinic (6.9 +/- 0.3 to 5.6 +/- 0.3; P < 0.01). These clinical data suggest that age is an important variable in opioid dose escalation. Although factors other than opioid tolerance can result in dose escalation, it is possible that older patients may have a reduced rate of tolerance development.

Intrathecal Morphine and Bupivacaine for Phantom Limb Pain: A Case Report

Besides the causes and prevention issues, chronic nonmalignant pain must be considered as a combination of multidimensional disorder of neurophysiology, behavior, culture, social, economic aspects.

Efficacy and safety of transdermal fentanyl and sustained-release oral morphine in patients with cancer and chronic non-cancer pain

PURPOSE

To evaluate effectiveness and safety information of transdermal fentanyl (TDF) (Duragesic/Durogesic) and sustained-release oral morphine (SRM) in cancer pain (CP) and chronic non-cancer pain (NCP), a pooled analysis was conducted on datasets of published, open label, uncontrolled (no comparator group) and randomised controlled (with SRM as comparator) studies of TDF.

PATIENTS AND METHODS

Eight trials with treatment durations of at least 28 days met the inclusion criteria. The effectiveness analysis assessed changes in average pain and pain 'right now' scores between baseline and Day 28. The safety analysis evaluated the incidence of adverse events (AEs) reported within the first 28 days of treatment with TDF or SRM. Subgroup analyses included pain type, gender, age, weight, and body mass index.

RESULTS

Pooled efficacy data were available from 1220 patients; these showed that both TDF and SRM were effective in improving pain 'right now' scores (0-100 scale) from baseline to Day 28. The improvement was significantly more pronounced in the TDF treatment group (-26.7 +/- 31.3 for TDF, -18.7 +/- 30.9 for SRM, p = 0.002). This favourable effect of TDF was most apparent amongst patients with NCP. Data concerning AEs were available from over 2500 patients with CP (3 out of 10 patients) or chronic NCP (7 out of 10 patients). Significantly fewer patients in the TDF than in the SRM group reported any AE (72% vs. 87% respectively; p < 0.001), or an AE leading to the study drug being permanently discontinued (16% vs. 23% respectively; p < 0.001). Constipation and somnolence occurred considerably less frequently in the TDF than in the SRM treatment group. This difference was statistically significant in both the CP and NCP subgroups.

CONCLUSION

This pooled data analysis provides expanded insight into the safety and effectiveness profile of transdermal fentanyl in patients with chronic pain. It shows significantly improved pain relief with transdermal fentanyl compared with sustained-release oral morphine, and supports current evidence of favourable tolerability of transdermal fentanyl, particularly with regard to reduced constipation and somnolence.