Randomised trial of oral morphine for chronic non-cancer pain

Prolonged treatment with transdermal fentanyl in neuropathic pain

Forty-eight patients with noncancer neuropathic pain who had participated in a randomized controlled trial with intravenous fentanyl (FENiv) infusions received prolonged transdermal fentanyl (FENtd) in an open prospective study. Pain relief, side effects, tolerance, psychological dependence, mood changes, and quality of life were evaluated. The value of clinical baseline characteristics and the response to FENiv also was evaluated in terms of the outcome with long-term FENtd. Eighteen patients stopped prematurely because of insufficient pain relief, side effects, or both. Among the remaining 30 patients completing the 12-week dose titration protocol, pain relief was substantial in 13 and moderate in five. Quality of life improved (23%, P < 0.01). Psychological dependence or the induction of depression was not observed. In only one patient did tolerance emerge. There was a significant positive correlation between the pain relief obtained with FENiv and that with prolonged FENtd (r = 0.59, P < 0.0001). We conclude that (1) long-term transdermal fentanyl may be effective in noncancer neuropathic pain without clinically significant management problems and (2) A FENiv-test may assist in selecting neuropathic pain patients who might benefit from prolonged treatment with FENtd.

The use of opioid drugs in management of chronic orofacial pain

The use of opioid analgesics for the management of patients with chronic pain is controversial. However, randomized and double-blind clinical trials have shown that in select groups of patients with chronic pain, the daily administration of oral opioids decreases pain levels and improves quality of life. This article provides a review of the most recent basic and clinical research supporting the rationale for the use of opioids in a select group of patients with chronic orofacial pain. Critical to the employment of this technique are proper patient evaluation and use of comprehensive management strategies. This management scheme should be reserved for patients with chronic pain that is refractory to most nonopioid therapy. The primary reason for the clinician's reluctance to initiate long-term opioid therapy for their patients with chronic pain is the potential risk of developing opioid tolerance, dependence, or addiction. In contrast to these beliefs, studies have shown a nonexistent to low risk of opioid dependence or addiction behavior with administration of scheduled oral opioids in chronic pain patients. It is essential that potential patients for this type of therapy have been carefully screened and have not had a history of drug addiction. The criteria to be evaluated when considering opioid therapy for chronic orofacial pain control include 1) inadequate pain diminution from prior nonopioid therapy, 2) negative history of substance abuse, 3) definitive determination that the pain being treated is of physiologic rather than psychologic origin, 4) a willingness to adhere to an "opioid contract" between the doctor and patient, 5) compliance with a scheduled, rather than "as needed" or "breakthrough," administration of an oral opioid, and 6) close clinical follow-up to evaluate pain relief, return to daily activities, and titration of drug levels. If these criteria are followed, administration of oral opioids may be a successful means of decreasing the patient's debilitating chronic pain to tolerable levels, enabling an improvement in the quality of life and return to function.

[Intrathecal opioids in chronic non-malignant pain: relief and life quality]

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.

The use of nonopioid drugs in management of chronic orofacial pain

Although controversial, opioid analgesics have been prescribed for patients with chronic facial pain. Based primarily on survey data and a few well-controlled clinical trials, long-term opioid treatment provides adequate pain reduction in 41% to 100% of patients with chronic nonmalignant pain. However, only 25% of chronic facial pain patients reported adequate pain relief with chronic opioid treatment. Work, home, and school function are generally reestablished or maintained during chronic opioid treatment, but 25% to 38% of patients remain dysfunctional, and one study indicated that 20% of patients became dysfunctional during treatment. Chronic opioid treatment is associated with many transient side effects; constipation, dizziness, nausea, vomiting, itching, and fatigue have been reported in 5% to 42% of patients taking opioids over 1 year. Although survey studies suggest that the risks of addiction are low in typical patients, drug abuse rates up to 17.3% and prescription abuse rates up to 27.6% were reported within groups of chronic opioid users. Chronic opioid use induces analgesic tolerance and physical dependence, which may result in a serious abstinence syndrome in users and children born to users. Chronic opioid use also may induce harmful immune system changes, diminish cognitive and motor function, and produce nociceptive hyperexcitability. This article shows that the use of long-term opioids for chronic facial pain is not justified based on the available data. Despite these perceived problems, there is anecdotal evidence that chronic facial pain patients will respond positively to opioid analgesics. In our experience, the pain assessment scale and a modification of the World Health Organization's three-step analgesic ladder, which prescribes nonopioid analgesics, can be the starting point for the successful management of chronic facial pain.

Outcome of chronic opioid therapy for non-cancer pain

Potential iatrogenic mood and cognitive declines associated with long-acting opioid therapy were examined in 19 patients receiving long-acting oral opioid medications and compared to ten patients receiving usual care. Pain, mood, and cognitive function were measured before and after achieving stable doses. In addition to reducing pain, long-acting opioid medication reduced anxiety and hostility. No declines in cognitive function were associated with the long-acting opioid medications, and the group receiving long-acting opioid medications showed significant improvement on a measure of psychomotor speed and sustained attention. Both patient groups reported significant reductions in perceived impairment in daily activities due to pain. Treatment responders taking long-acting opioid medications (63%) were taking a significantly lower dose at follow-up than the treatment non-responder group. These findings suggest that long-acting opioid medications can improve mood and do not impair cognitive functioning in patients with chronic non-cancer pain.

Transdermal fentanyl as treatment for chronic low back pain

Management of chronic low back pain often includes oral opioid use. The effectiveness of therapy is dependent upon compliance, which in turn is dependent upon response, side effects, access, and convenience. Our hypothesis was that a transdermal fentanyl system would provide more effective pain management than oral opioids. Fifty patients with chronic low back pain were examined. After litration to levels corresponding to current oral opioid use, each patient was maintained on transdermal fentanyl for one month. Oral opioid therapy was then resumed. Their experience was assessed with the a visual analogue scale for pain intensity, a numerical pain score, the Oswestry disability questionnaire, the pain disability index, and the Verran Snyder-Halpern sleep scale. Significant improvement in pain relief and disability was found with transdermal fentanyl compared with oral opioids. Mild opioid side effects were common, but easily controlled. Use of transdermal fentanyl is an effective alternative to oral opioids for managing chronic low back pain.

Intraarticular morphine analgesia in chronic pain patients with osteoarthritis

Controlled clinical studies have shown that local administration of morphine can significantly relieve acute postoperative pain. This analgesic effect is long-lasting (up to 48 h) and is mediated by peripheral opioid receptors. Experimental evidence shows that analgesic effects of peripheral opioids and the density of opioid receptors on peripheral sensory nerves increase with the duration of painful inflammatory processes. This study examines the analgesic effects of 1 mg of morphine injected into the arthritic knee joints of two groups of chronic pain patients (n = 23) suffering from osteoarthritis. Using a randomized, double-blind cross-over design, patients received either an intraarticular injection of morphine and intravenous saline (Group A, n = 13) or an intraarticular injection of saline and intravenous morphine (Group B, n = 10) during Phase I. Seven days later, patients crossed over to the opposite treatment (Phase II). During Phase I, intraarticular morphine resulted in significantly greater pain relief than intraarticular saline, and this effect was present at rest as well as during movement. The analgesic effect was surprisingly long-lasting and extended into Phase II, a carry-over effect that prevented the analysis of Phase II. No side effects were reported. The treatment of arthritic pain by peripherally acting opioids may be a promising alternative to currently available medications that have serious side effects.

Randomised double-blind active-placebo-controlled crossover trial of intravenous fentanyl in neuropathic pain

BACKGROUND

The effectiveness of opioid analgesics in non-cancer neuropathic pain is unpredictable and can be disappointing. It is not clear whether opioids, when effective, relieve pain by decreasing pain intensity or pain unpleasantness or by their sedative effect. The aim of this prospective randomised double-blind placebo-controlled crossover trial was to assess relief of pain intensity and pain unpleasantness with intravenous infusions of fentanyl.

METHODS

We compared the analgesic effect of intravenous dose titration of fentanyl with diazepam (active placebo) or saline (inert placebo) in 53 patients with different types of neuropathic pain. Patients were randomly assigned two consecutive infusions: fentanyl plus diazepam (27 patients) or fentanyl plus saline (26 patients). Study medication was infused at a constant rate for a maximum of 5 h. Pain, sedation, and side-effects were assessed from the start of infusion for 8 h. The primary outcome measure was maximum relief of pain intensity.

FINDINGS

One patient in the fentanyl/diazepam group and two in the fentanyl/saline group were withdrawn. Maximum relief of pain intensity was better with fentanyl than with diazepam (66% [95% CI 53-80] vs 23% [12-35]) or with saline (50% [36-63] vs 12% [4-20]). The beneficial effect of fentanyl was independent of the type of neuropathic pain and the degree of sedation. Fentanyl therapy produced equal relief of pain intensity and pain unpleasantness, whereas diazepam and saline did not reduce either pain index. Patients reported significantly more side-effects while receiving fentanyl than during diazepam or saline infusion (p < 0.0001), but none of the side-effects was severe.

INTERPRETATION

Fentanyl may relieve non-cancer neuropathic pain by its intrinsic analgesic effect. The clinical characteristics of neuropathic pain do not predict response to opioids.

Pharmacologic treatments for temporomandibular disorders

Drugs are widely used in the management of acute and chronic orofacial pain. Whereas the use of analgesics for acute orofacial pain is well documented through hundreds of controlled clinical trials, the use of a broad spectrum of drugs for chronic pain is based on very few studies. In the absence of data supporting a therapeutic benefit for a drug used chronically for pain, toxicity associated with the drug can still occur. It is critical, therefore, to assess the balance between therapeutic benefit and safety. This article reviews current evidence supporting the use of several drug classes for temporomandibular disorders (TMD) and identifies therapeutic controversies in need of further research.

Opioid therapy for chronic nonmalignant pain: a review of the critical issues

The controversy surrounding the long-term use of opioid drugs in patients with nonmalignant pain has intensified in recent years. This debate is driven by a new willingness to consider the potential benefits of an approach that has been traditionally rejected as invariably ineffective and unsafe. The published literature continues to be very limited, but a growing clinical experience, combined with a critical reevaluation of issues related to efficacy, safety, and addiction or abuse, suggests that there is a subpopulation of patients with chronic pain that can achieve sustained partial analgesia from opioid therapy without the occurrence of intolerable side effects or the development of aberrant drug-related behaviors. Future research must confirm this impression through controlled clinical trials and clarify those factors that may predict therapeutic success or failure. For the present, the clinician who contemplates this approach must have a clear grasp of the relevant issues and an understanding of the guidelines for treatment and monitoring that have proved useful in practice.

Opioid therapy for chronic nonmalignant pain: clinician's perspective

During the past decade, debate has intensified about the role of long-term opioid therapy in the management of chronic nonmalignant pain. Specialists in pain management have discussed the issues extensively and now generally agree that a selected population of patients with chronic pain can attain sustained analgesia without significant adverse consequences. This perspective, however, is not uniformly accepted by pain specialists and has not been widely disseminated to other disciplines or the public. Rather, the more traditional perspective, which ascribes both transitory benefit and substantial cumulative risk to long-term opioid therapy, continues to predominate. According to this perspective, the inevitability of tolerance limits the possibility of sustained efficacy, and other pharmacological properties increase the likelihood of adverse outcomes, including persistent side-effects, impairment in physical and psychosocial functioning, and addiction. If accurate, these outcomes would indeed justify the withholding of opioid therapy for all but the most extreme cases of chronic nonmalignant pain.