Long-term intraspinal infusions of opioids in the treatment of neuropathic pain. [Intrathecal opioids in chronic non-malignant pain: relief and life quality]. Opioid therapy for chronic noncancer back pain. A randomized prospective study. Long-term oral opioid therapy in patients with chronic nonmalignant pain. Lack of analgesic effect of opioids on neuropathic and idiopathic forms of pain. Effect of neurolytic celiac plexus block on pain relief, quality of life, and survival in patients with unresectable pancreatic cancer: a randomized controlled trial. The effect of opioids on phantom limb pain and cortical reorganization. Long-term management of noncancer pain with transdermal therapeutic system-fentanyl. Opioid substitution to improve the effectiveness of chronic noncancer pain control: a chart review.
Long-term intraspinal infusions of opioid drugs are being increasingly utilized in patients with noncancer pain. Despite this, there is a lack of long-term information, including success and failure rates for pain relief and technical problems. During a 5-year period, 18 noncancer patients underwent implantation of programmable infusion pumps for long-term intrathecal opioid infusion. Patients had (a) neuropathic pain, (b) had failed or been ineligible for noninvasive treatments, and (c) obtained greater than 50% pain relief with intrathecal trial infusions of morphine sulfate or sufentanil citrate. A disinterested third-party reviewer evaluated patients at the most recent follow-up. Sixty-one percent (11/18) of patients had good or fair pain relief with mean follow-up 2.4 +/- 0.3 years (0.8-4.7 years). Average numeric pain scores decreased by 39% +/- 4.3%. Five of the 11 responders required lower opioid doses (12-24 mg/day morphine) and the remaining six patients required higher opioid doses (> 34 mg/day morphine). Failure of long-term pain relief occurred in 39% (7/18) despite good pain relief in trial infusions and the use of both morphine and sufentanil. Technical problems developed in 6/18 patients but appeared to be preventable with further experience. Long-term intrathecal opioid infusions can be effective in treatment of neuropathic pain but might require higher infusion doses. The use of opioids for treatment of non-malignant pain is controversial. The evaluation of pain relief and of the quality of life of 11 severely incapacitated chronic non-cancer pain patients treated with long term intrathecal infusion of opioids trought implantable pumps was performed. The mean duration of pain complaints was 5.3 years. The mean pain intensity was 8.6. In 7 patients, pain episodes lasted at least 6 hours daily. The mean duration of the therapy was 19.6 months. After the treatment the mean pain score became 3.9. In only 1 patient, the duration of pain episodes was still longer than 6 hours. Quality of life improved in 36.36% of the cases. The long term spinal opioids through implantable pumps for non-malignant pains results in pain relief but not necessarily improves the quality of life. A randomized, open, long-term, repeated-dose comparison of an anti-inflammatory drug and two opioid regimens in 36 patients with back pain.
                To examine the long-term safety and efficacy of chronic opioid therapy in a randomized trial of patients with back pain.
                All participants underwent a 4-week washout period of no opioid medication before being randomly assigned to one of three treatment regimens for 16 weeks: 1) naproxen only, 2) set-dose oxycodone, or 3) titrated-dose oxycodone and sustained-release morphine sulfate. All patients then were assigned to a titrated dose of opioids for 16 weeks and then gradually tapered off their medication for 12 weeks. Finally, all participants were monitored for a 1-month posttreatment washout period. Each patient was called once a week for a report on pain, activity, mood, medication, hours awake, and adverse effects and was monitored carefully for signs of abuse and noncompliance.
                Weekly reports during the experimental phase showed the titrated-dose group to have less pain (P < 0.001) and less emotional distress (P < 0.001) than the other two groups. Both opioid groups were significantly different from the naproxen-only group. During the titration phase, patients also reported significantly less pain and improved mood. Few differences were found in activity or hours asleep, or between average pretreatment and posttreatment phone-interview and questionnaire variables. No adverse events occurred, and only one participant showed signs of abuse behavior.
                The results suggest that opioid therapy has a positive effect on pain and mood but little effect on activity and sleep. Opioid therapy for chronic back pain was used without significant risk of abuse. However, tapered-off opioid treatment is palliative and without long-term benefit. In contrast to the use of opioids for the treatment of acute and chronic cancer pain, the administration of chronic opioid therapy for pain not due to malignancy remains controversial. We describe 100 patients who were chronically given opioids for treatment of nonmalignant pain. Most patients experienced neuropathic pain or back pain. We used sustained-release dihydrocodeine, buprenorphine, and sustained-release morphine. Pain reduction was measured with visual analogue scales (VAS), and the Karnofsky Performance Status Scale was used to assess the patient's function. Good pain relief was obtained in 51 patients and partial pain relief was reported by 28 patients. Only 21 patients had no beneficial effect from opioid therapy. There was a close correlation between the sum and the peak VAS values (r = 0.983; p less than 0.0001) and pain reduction was associated with an increase in performance (p less than 0.0001). The most common side effects were constipation and nausea. There were no cases of respiratory depression or addiction to opioids. Our results indicate that opioids can be effective in chronic nonmalignant pain, with side effects that are comparable to those that complicate the treatment of cancer pain. The aim of the present study has been to assess the responsiveness of various types of chronic pain to opioids given i.v. and tested against placebo in a double-blind, randomized fashion. Pain classified as primary nociceptive was effectively alleviated (P greater than 0.001) while neuropathic deafferentation pain was not significantly influenced by morphine or equivalent doses of other opioids. Also 'idiopathic' pain, defined as chronic pain with no or little demonstrable pathology, failed to respond. The results were not related to whether the patients were regular users of narcotic analgesics or not. The outcome of our double-blind opioid test has proved useful to justify a continued, or discontinued, use of narcotic medication in individual patients. It may also support the indication and choice of invasive stimulation procedures (spinal cord or brain). The results of the study illustrate the misconception of chronic pain as an entity and highlight the importance of recognizing different neurobiological mechanisms and differences in responsiveness to analgesic drugs as well as to non-pharmacological modes of treatment. The opioid test has thus become a valuable tool in pain analysis and helpful as a guide for further treatment. Pancreatic cancer is an aggressive tumor associated with high mortality. Optimal pain control may improve quality of life (QOL) for these patients.
                To test the hypothesis that neurolytic celiac plexus block (NCPB) vs opioids alone improves pain relief, QOL, and survival in patients with unresectable pancreatic cancer.
                Double-blind, randomized clinical trial conducted at Mayo Clinic, Rochester, Minn. Enrolled (October 1997 and January 2001) were 100 eligible patients with unresectable pancreatic cancer experiencing pain. Patients were followed up for at least 1 year or until death.
                Patients were randomly assigned to receive either NCPB or systemic analgesic therapy alone with a sham injection. All patients could receive additional opioids managed by a clinician blinded to the treatment assignment.
                Pain intensity (0-10 numerical rating scale), QOL, opioid consumption and related adverse effects, and survival time were assessed weekly by a blinded observer.
                Mean (SD) baseline pain was 4.4 (1.7) for NCPB vs 4.1 (1.8) for opioids alone. The first week after randomization, pain intensity and QOL scores were improved (pain intensity, P< or =.01 for both groups; QOL, P<.001 for both groups), with a larger decrease in pain for the NCPB group (P =.005). From repeated measures analysis, pain was also lower for NCPB over time (P =.01). However, opioid consumption (P =.93), frequency of opioid adverse effects (all P>.10), and QOL (P =.46) were not significantly different between groups. In the first 6 weeks, fewer NCPB patients reported moderate or severe pain (pain intensity rating of > or =5/10) vs opioid-only patients (14% vs 40%, P =.005). At 1 year, 16% of NCPB patients and 6% of opioid-only patients were alive. However, survival did not differ significantly between groups (P =.26, proportional hazards regression).
                Although NCPB improves pain relief in patients with pancreatic cancer vs optimized systemic analgesic therapy alone, it does not affect QOL or survival. The efficacy of oral retarded morphine sulphate (MST) was tested against placebo in a double-blind crossover design in 12 patients with phantom limb pain after unilateral leg or arm amputation. Two counterbalanced treatment phases of 4 weeks each were initiated with an intravenous test infusion of MST or Placebo. The titration phase was 2 weeks. The dose of MST was titrated to at least 70 mg/day and at highest 300 mg/day. Pain intensity was assessed hourly on visual analog scales during a 4-week treatment-free phase, both treatment phases and at two follow-ups (6 and 12 months). Reorganization of somatosensory cortex, electric perception and pain thresholds as well as selective attention were measured pre- and post-treatment. A significant pain reduction was found during MST but not during placebo. A clinically relevant response to MST (pain reduction of more than 50%) was evident in 42%, a partial response (pain reduction of 25-50%) in 8% of the patients. Neuromagnetic source imaging of three patients showed initial evidence for reduced cortical reorganization under MST concurrent with the reduction in pain intensity. Perception and pain thresholds were not significantly altered whereas attention was significantly lower under MST. Thus, opioids show efficacy in the treatment of phantom limb pain and may potentially influence also cortical reorganization. These data need to be replicated in larger patient samples. Transdermal therapeutic system-fentanyl (TTS-F) has been extensively studied in cancer pain management. However, few studies have addressed the long-term management of noncancer pain, especially when it relates to neuropathic pain. A total of 529 patients were recruited into this prospective open-label study to determine the safety and effectiveness of TTS-F in relation to quality-of-life (QOL) stratified according to pain type and etiology. TTS-F significantly improves QOL within 28 days, and pain management within 48 hours. The frequency of side effects rapidly decreases over time, and patients not experiencing adequate pain management are identified within 28 days. The median duration of therapy for effective pain management was 10 months, and 90% of patients sustained such efficacy. TTS-F offers statistically significant increases in QOL-Short Form 12 (including the Physical Component Scale and Mental Component Scale measures) and pain control (Greek Brief Pain Inventory) from one time point to the next (P <.0001). These improvements are not influenced by pain type or etiology. TTS-F is a safe and effective pain management system independent of patient characteristics and demographic factors. What is of most importance is that in those patients with neuropathic pain, for whom opioids have long been thought to be ineffective, similar effectiveness is demonstrated when compared to patients with nociceptive pain. We evaluated the efficacy and tolerability of opioids in the long-term management of chronic noncancer pain. This retrospective chart review included 86 outpatients who started receiving, between 1994 and 1998, long-acting opioids. For each patient, the number of different opioids used and the efficacy and tolerability of each opioid prescribed were noted. During a mean follow-up of 8.8 +/- 6.3 mo, the number of opioids used by each patient was 2.3 +/- 1.4. Patient diagnoses were: back pain (31), neuropathy (20), joint pain (13), visceral pain (7), reflex sympathetic dystrophy (7), headache (5), fibromyalgia (3). The first opioid prescribed was effective for 36% of patients, was stopped because of side effects in 30%, and was stopped for ineffectiveness in 34%. Of the remaining patients, the second opioid prescribed after the failure of the first was effective in 31%, the third in 40%, the fourth in 56%, and the fifth in 14%. There was one case of addiction and no case of tolerance. We conclude that if it is necessary to change the opioid prescription because of intolerable side effects or ineffectiveness, the cumulative percentage of efficacy increases with each new opioid tested. Failure of one opioid cannot predict the patient's response to another. Implications: This study showed that if a patient receiving chronic opioid therapy experiences an intolerable side effect or if the drug is ineffective, changing to a different opioid may result in a lessening or elimination of the side effect and/or improved analgesia.
Short-term studies provide only equivocal evidence regarding the efficacy of opioids in reducing the intensity of neuropathic pain, whereas intermediate-term studies demonstrate significant efficacy of opioids over placebo, which is likely to be clinically important. Reported adverse events of opioids are common but not life threatening. Further randomized controlled trials are needed to establish long-term efficacy, safety (including addiction potential), and effects on quality of life.