Analgesic and psychoactive drugs in the chronic pain patient

In contrast to the management of pain in patients with malignant disease, where manipulation of analgesic and psychoactive drugs may be necessary and effective, the elimination of drug use is a primary goal in programs for patients with chronic pain of benign rig in.; Drug use is often a significant component of pain behavior and, therefore, it is important to alter the use of drugs in freeing the patient of the chronic pain syndrome. Elimination of the unwanted side effects and medical complications of drug use may contribute significantly to the patient's physical and psychological well-being. Also, because many of these drugs are associated with physiological or psychological dependency, it also becomes important to identify and treat drug abuse and chemical dependency, which is a primary problem in a subgroup of chronic pain patients. This discussion will focus on the relationship of drug use to chronic pain behavior and methods of medication withdrawal. In addition, the problems of chemical dependency and its identification and management will be discussed.J Orthop Sports Phys Ther 1984;5(6):315-317.     

Implantable technology for pain management

Chronic pain occurs in up to half the adult population at some point in their lives, with 10% of this group disabled by pain. Unrelieved chronic pain is a major socioeconomic and healthcare problem and successful management of affected individuals requires a full range of treatment options. Since Melzack and Wall’s Gate Theory of Pain was first proposed, an improved understanding of neuroscience has lead to development of implantable ‘neuromodulatory’ technologies for refractory pain. Simply put, such technologies involve drug delivery to, or electrical stimulation of neural pathways. In the pain management context, neuromodulation aims to reduce afferent activity within pain pathways by targeted electrical neurostimulation or drug delivery into CSF. Targets for implanted neurostimulators include the spinal cord, peripheral nerves or brain, while implantable pumps deliver analgesic drugs to intrathecal or intracerebroventricular sites. Implantable neuromodulation therapies are expensive, invasive and prone to side effects and complications. Clinicians and health professionals involved with implantation and aftercare of such devices require a high level of expertise. In spite of these challenges the uptake of these therapies continues to rise worldwide as does the evidence for cost effectiveness due to reduced expenditure on conventional medical management. To optimize outcomes, patients being considered for neuromodulatory therapies must undergo comprehensive biopsychosocial assessment, be fully informed regarding risks and have realistic expectations. This article will focus on spinal cord stimulation and intrathecal drug delivery (ITDD) for the non-expert.     

Postoperative pain management—clinical practice is still not optimal

Major progress in clinical pain assessment and management has been achieved in the last decade. More effective analgesic drugs and improved techniques for pain management have been introduced. However, medical reports published during the last few years on postoperative pain management (POPM) indicate that moderate or even severe pain is still rather commonly experienced by surgical patients in the early postoperative period and that worst-pain-episodes may occur even in the late postoperative phase. Insufficient relief of postoperative pain seems a more common problem on surgical wards than on a postanaesthesia care unit (PACU). The aims of POPM are to inhibit autonomic trauma-induced nociceptive impulses that may result in functional disturbances of vital organs and thereby affect the incidence of potentially severe complications influencing clinical outcome. Considering that recent studies continue to show sub-optimal pain management despite the availability of effective drugs and analgesic techniques it must be considered essential to identify possible barriers to effective pain management in clinical practice so that necessary improvements in POPM routines can be carried out.     

Additive analgesic effect of codeine and paracetamol can be detected in strong, but not moderate, pain after Caesarean section

Background : A randomized, double-blind, placebo-controlled single oral dose study was done in order to examine whether codeine has an additive analgesic effect to that of paracetamol for moderate and strong postoperative pain after abdominal surgery. The maximum recommended single dose of paracetamol 1000 mg (Paracet®) was compared with a combination of a submnximal dose of paracetamol 800 mg plus codeine 60 mg (Paralgin forte®) and placebo for pain relief after Caesarean section in 125 patients. Methods : Visual analogue pain intensity score (VAS 0–100 mm) and categorical pain relief score were recorded for 6 hours after the study drug intake. The main efficacy variables analyzed were: pain intensity difference and summed pain intensity differences during the first 3 and 6 h after study drug intake, total pain relief during the first 3 and 6 h, global evaluation score at the end of the observation period, and time to rescue analgesic. Results : Because of protocol violations, 17 patients were excluded from the analysis of effects. Among the 108 patients included in the analysis of analgesic effect, 49 patients had moderate baseline pain (VAS between 40 and 60 mm on a 100 mm scale), and 59 patients had strong baseline pain (VAS more than 60 mm). In patients with strong baseline pain, statistically highly significant differences were documented in efficacy variables between the active drugs and placebo and between the two active drugs. However, in patients with moderate baseline pain, no differences were found between the study drugs in any of the analgesic efficacy variables. Conclusion : This study thus confirms that codeine has additive analgesic effect to paracetamol in pain after surgery. Our results show the importance of initial pain intensity in postoperative assessment of analgesic drugs. Assay-sensitivity and test power are increased by selecting patients with sufficiently high initial pain intensity and by comparing groups of patients with identical surgery and similar demographic variables.     

Management of severe pain in terminal care

Cancer pain occurs in about 30% of patients at diagnosis but increases in prevalence with advanced disease. Recent surveys suggest that over 80% of patients with advanced cancer have pain and about half of these patients experience pain that is inadequately controlled. This suggests that despite the 80% efficacy of standardized management approaches to cancer pain, patients with severe pain are likely to be encountered often in clinical practice. This is often the result of a combination of factors including inadequate pain assessment, under-dosing of medication, failure to educate and monitor patients and their carers, as well as a failure of medication to relieve pain. Assessment of a patient with cancer who is in pain should not differ from the assessment of any other patient with pain. Pain in a cancer patient may not be caused by cancer and opioids may be inappropriate. Treatment of cancer-related pain relies on a stepwise approach using non-opioid and opioid analgesics. Doses need to be titrated against analgesic effect and the presence of any adverse effects. Patients with cancer are often frail, elderly, and have some renal or hepatic impairment. They can be prone to the adverse effects of medicines. Neuropathic pain usually requires a combination of standard analgesic medicines and co-analgesic drugs and there is good evidence that this can result in good pain control. Patients with breakthrough (or episodic) pain are particularly challenging to treat and require additional approaches, such as radiotherapy, surgery or bisphosphonates.     

Rational pharmacotherapeutic pain treatment in seronegative spondyloarthropathies

The aims of management in seronegative spondiloarthritides are to control pain and inflammation, maintain optimal mobility of spine and peripheral joints, restoration and preservation of functional ability, prevent contractures and deformities. Non-steroidal anti-inflammatory drugs are the basis of drug treatment. Numerous non-steroidal anti-inflammatory drugs have been shown to reduce pain and inflammation. Apart from non-steroidal anti-inflammatory drugs, in order to control the pain pure analgesics and weak opioids are the most often used drugs. In this paper is discussed use of these drugs in patients with seronegative spondyloarthritides.     

Nonsteroidal anti-inflammatory drugs for low back pain: a systematic review within the framework of the Cochrane Collaboration Back Review Group

STUDY DESIGN: A systematic review of randomized and double-blind controlled trials was performed. SUMMARY OF BACKGROUND DATA: Nonsteroidal anti-inflammatory drugs are the most frequently prescribed medications worldwide and are widely used for patients with low back pain. OBJECTIVES: To assess the effects of nonsteroidal anti-inflammatory drugs in the treatment of nonspecific low back pain with or without radiation, and to assess which type of nonsteroidal anti-inflammatory drug is most effective. METHODS: For this study, the Cochrane Controlled Trials Register, Medline and Embase, and reference lists of articles were searched. Two reviewers blinded with respect to authors, institution, and journal independently extracted data and assessed the methodologic quality of the studies. If data were considered clinically homogeneous, a meta-analysis was performed. If data were considered clinically heterogeneous, a qualitative analysis was performed using a rating system with four levels of evidence: strong, moderate, limited, and no evidence. RESULTS: This review involved 51 trials and 6057 patients. Of these trials, 16 (31%) were of high quality. The pooled relative risk for global improvement after 1 week was 1.24 (95% confidence interval [CI] = 1.10-1.41), and for additional analgesic use was 1.29 (95% CI = 1.05-1.57), indicating a statistically significant but small effect in favor of nonsteroidal anti-inflammatory drugs as compared with a placebo. The results of the qualitative analysis showed that there is conflicting evidence (Level 3) that nonsteroidal anti-inflammatory drugs are more effective than paracetamol for acute low back pain, and that there is moderate evidence (Level 2) that nonsteroidal anti-inflammatory drugs are not more effective than other drugs for acute low back pain. There is strong evidence (Level 1) that various types of nonsteroidal anti-inflammatory drugs are equally effective for acute low back pain. CONCLUSIONS: The evidence from the 51 trials included in this review suggests that nonsteroidal anti-inflammatory drugs are effective for short-term symptomatic relief in patients with acute low back pain. Furthermore, there does not seem to be a specific type of nonsteroidal anti-inflammatory drug that is clearly more effective than others. Sufficient evidence on chronic low back pain still is lacking.     

Pharmacological treatment of chronic pain

Pain transmission involves numerous pathways, transmitters and receptors. This suggests that there will never be a single ‘magic bullet’ antinociceptive drug. Optimum pain control often requires a multimodal approach using several analgesics. The primary goals in managing chronic pain are to reduce pain and most importantly to improve function. The rapid control of pain symptoms can reduce the risk of chronicity.The optimal pharmacological treatment for chronic pain is that the medication should be taken ‘round the clock’ rather than ‘as required’. It is easier to keep pain at bay rather than trying to control it after it has resurfaced. The World Health Organization (WHO) 3-step analgesic ladder has proved successful in controlling over 80% of cancer pain. It is also appropriate for non-malignant nociceptive pain and uses conventional analgesic drugs. The drugs used in Step 1 are paracetamol (acetaminophen), non-steroidal anti-inflammatory drugs (NSAIDs) and cyclo-oxygenase II inhibitors (COX II). Codeine and other opioids are used for moderate pain in Step 2, and the potent opioid drugs, such as morphine, are used in Step 3. Local modulation uses the local application of transcutaneous electrical nerve stimulation (TENS), acupuncture or regional analgesic block by injection into tissue or around nerves using local anaesthetics, opioids, steroids, alpha 2 agonists (e.g. clonidine) and/or NMDA antagonists (e.g. ketamine). For neuropathic pain, adjuvant drugs such as antidepressants, anticonvulsants and antiarrhythmics are more effective. The antidepressant amitriptyline is the gold standard. Adjuvant analgesics appear to work by potentiating the dorsal inhibitory pathways of the spinal cord or stabilizing excitable neural fibres.     

Assessing pain in children

Acute pain is one of the most common experiences a child will have as a result of injury, illness or medical procedures. It is associated with anxiety, fear, stress and distress. Despite this, acute pain in a child is often inadequately assessed, managed and treated. The paediatric experience of acute pain involves the interaction of physiological, psychological, behavioural, developmental and situational factors. The subjectivity and multidimensional nature of pain requires clinicians to approach pain assessment using a combination of a child’s verbal report in conjunction with behavioural observation and physiological measures. Recognizing, treating and reassessing are essential components of acute pain assessment. Wherever possible a proactive approach should be adopted, where pain assessment is integrated into the holistic admission procedure rather than performed in isolation when the child is in pain. To provide effective pain management in children, healthcare professionals should use age and developmentally appropriate pain assessment tools, anticipate painful experiences and intervene accordingly. This article describes pain assessment tools for the management of acute pain in infants and children (excluding neonates).     

Use of antiepileptic drugs in patients with kidney disease

The number of medications used to treat different types of seizures has increased over the last 10-15 years. Most of the newer antiepileptic drugs (AEDs) are likely to be unfamiliar to many nephrologists. For both the older and newer AEDs, basic pharmacokinetic information, recommendations for drug dosing in patients with reduced kidney function or who are on dialysis, and adverse renal and fluid-electrolyte effects are reviewed. Newer AEDs are less likely to have significant drug-drug interactions than older agents, but are more likely to need dosage adjustment in patients with reduced kidney function. The most common renal toxicities of these drugs include metabolic acidosis, hyponatremia, and nephrolithiasis; interstitial nephritis and other adverse effects are less common. Little is known about the clearance of most of the newer AEDs with high-efficiency hemodialyzers or with peritoneal dialysis. Monitoring of drug levels when available, careful clinical assessment of patients taking AEDs, and close collaboration with neurologists is essential to the management of patients taking AEDs.     

Cancer pain management

Pain occurs in more than 80% of cancer patients before death. Because of the increase in the frequency of cancer deaths worldwide, it is imperative to address cancer pain as a public health problem. Until recently, educational efforts were focused on treatment issues rather than adequate assessment. The approach to pain intensity as a multidimensional construct has helped in focusing treatments and identifying prognostic factors. Valid tools have been developed that allow multidisciplinary assessment of these prognostic factors and their complex interrelationship with the analgesic response. As a result of increased opioid exposure, patients are currently developing newer toxicities, mostly central excitability including delirium, myoclonus, grand mal seizures, and hyperalgesia. The observation that more than 80% of patients will require alternate routes for opioid delivery before death led to the development of a number of novel and effective alternate routes for delivery. Finally, in recent years it has become evident that some specific pain syndromes need to be addressed using specific assessment and management techniques. Incidental pain, somatization, neuropathic pain, and cancer pain in patients with alcoholism and drug addiction are some of these syndromes.     

Gabapentin and pregabalin for chronic neuropathic and early postsurgical pain: current evidence and future directions

PURPOSE OF REVIEW: Gabapentin and pregabalin bind to the alpha-2-delta calcium channel subunit and represent a novel analgesic drug class. The evidence base supporting their use for chronic neuropathic and early postsurgical pain is reviewed. RECENT FINDINGS: Multiple, large, high-quality trials have demonstrated the safety and efficacy of gabapentin and pregabalin in neuropathic pain. Treatment-related improvement of pain and sleep positively impact upon quality of life. Sedation, dizziness and ataxia are important and relatively common adverse effects, however. Accumulating evidence indicates that gabapentin, and possibly pregabalin, also exert important effects following surgery. Multiple high-quality trials have demonstrated analgesic and opioid-sparing efficacy with gabapentin following various surgical procedures. Gabapentin and pregabalin reduce movement-evoked pain and this can lead to enhanced functional postoperative recovery. Postoperative opioid sparing is of questionable relevance since few trials have shown reduced opioid-related adverse effects. Sedation, dizziness and ataxia have been reported in only a few trials. Future larger-scale perioperative trials focused on safety assessment are needed, however. SUMMARY: Gabapentin and pregabalin are efficacious treatments for neuropathic and postsurgical pain. Future research addressing several specific questions would serve to better delineate their optimal roles in treating these and other pain conditions.     

Assessment of pain

Valid and reliable assessment of pain is essential for both clinical trials and effective pain management. The nature of pain makes objective measurement impossible. Acute pain can be reliably assessed, both at rest (important for comfort) and during movement (important for function and risk of postoperative complications), with one-dimensional tools such as numeric rating scales or visual analogue scales. Both these are more powerful in detecting changes in pain intensity than a verbal categorical rating scale. In acute pain trials, assessment of baseline pain must ensure sufficient pain intensity for the trial to detect meaningful treatment effects. Chronic pain assessment and its impact on physical, emotional, and social functions require multidimensional qualitative tools and health-related quality of life instruments. Several disease- and patient-specific functional scales are useful, such as the Western Ontario and MacMaster Universities for osteoarthritis, and several neuropathic pain screening tools. The Initiative on METHODS: Measurement, and Pain Assessment in Clinical Trials recommendations for outcome measurements of chronic pain trials are also useful for routine assessment. Cancer pain assessment is complicated by a number of other bodily and mental symptoms such as fatigue and depression, all affecting quality of life. It is noteworthy that quality of life reported by chronic pain patients can be as much affected as that of terminal cancer patients. Any assessment of pain must take into account other factors, such as cognitive impairment or dementia, and assessment tools validated in the specific patient groups being studied.     

Back pain in children

Back pain is a common reason for presenting to the paediatric spinal clinic. Most will have non-specific back pain without an identifiable cause, but there are serious pathologies that should be considered and excluded prior to coming to this conclusion. This article focuses on the assessment, differential diagnosis and overview of management of frequently encountered causes of back pain in children.     

Novel drug delivery systems in pain therapy

Pain is an unpleasant sensory experience resulting from damage to bodily tissues. It is considered a significant public health problem because it affects 1/5 of the world population and causes loss of great amounts of money. Pain reflects a mixture of pathological, psychological and genetic conditions that need deep understanding to be efficiently treated. If under-treated, pain results in serious immune and metabolic problems. Pain management faces many problems that limit its control. For instance, efficiency of pain killers is limited, pain killers give rise to serious side effects and inability of drug administration methods to help in pain control. Technology can overcome some of these problems and the introduction of implantable controlled drug delivery systems (CDDS), manufactured from biodegradable materials, offers a solution. Implantable CDDS provide good level of pain control, as they continuously provide drug, reduce side effects and improve patients' compliance. Biodegradable type of implantable CDDS are polymer based devices that are fabricated to locally deliver drugs in a pre-designed manner. They are currently a focus of research in the field of pain therapy in order to explore their chance to offer an alternative to the conventional methods for drug delivery. This paper aims to highlight the dimensions of pain issue and to overview the basics of drug release from polymers used for CDDS in pain management. In addition, it discusses the recent advances in the technologically designed drug delivery systems in the field of pain medicine and their clinical applications. Future perspectives are also presented.     

Postcesarean section pain prediction by preoperative experimental pain assessment

BACKGROUND: Postcesarean section pain is a common cause of acute pain in obstetrics, yet pain relief and patient satisfaction are still inadequate in many cases. The present study was conducted to determine whether preoperative assessment of experimental pain perception by quantitative sensory tests could predict the level of postcesarean section pain. METHODS: Fifty-eight women who were scheduled for elective cesarean section were enrolled in the study. Heat pain threshold and magnitude estimation of suprathreshold pain stimuli at 44 degrees-48 degrees C were assessed for both algosity (the sensory dimension of pain intensity) and unpleasantness 1 or 2 days before surgery. The day after the operation, the women reported the level of pain at the surgical wound on a visual analog scale at rest and during activity. Regression analysis was performed to evaluate the usefulness of preoperative scores in predicting postcesarean section pain. RESULTS: Postoperative visual analog scale scores at rest and during activity significantly correlated with preoperative suprathreshold pain scores at 44 degrees-48 degrees C (r = 0.31-0.58 for algosity and r = 0.33-0.74 for unpleasantness). The stimulus of 48 degrees C was found to be the best predictor of postoperative pain for both conditions (r = 0.434-0.527; P < 0.01). In contrast to suprathreshold pain stimuli, pain threshold was not correlated with postoperative pain. CONCLUSIONS: The results show that a simple and quick preoperative test is useful in identifying those women who will experience greater pain after a cesarean section. This test may be suggested for caregivers to tailor the postoperative treatment to specific patient needs and to improve postoperative outcome and patient satisfaction.     

Non-steroidal anti-inflammatory drugs in treatment of postoperative pain after cardiac surgery

PURPOSE: Non-steroidal anti-inflammatory drugs (NSAIDs) are used as analgesic in postoperative pain to reduce opioid side effects, such as drowsiness and nausea. However, NSAIDs have not been used extensively in cardiac surgical patients due to the fear of untoward effects on gastric, renal, and coagulation parameters. This study will evaluate the efficacy and safety of three NSAIDs for pain control in CABG patients. METHODS: One hundred and twenty patients scheduled for elective CABG surgery were enrolled in randomized, double blind, controlled study. Standardized fast track cardiac anesthesia was used. One dose of drug (75 mg diclofenac, 100 mg ketoprofen, 100 mg indomethacin, or placebo) was given pr one hour before tracheal extubation and a second dose 12 hr later. Pain was treated with morphine iv and acetaminophen po. Visual analogue pain scores were recorded at baseline, 3, 6, 12 and 24 hr after the first dose of drug. RESULTS: There were no differences among the groups in pain scores. Only patients who received diclofenac required less morphine than patients in the control group (P < 0.05). When the total amounts of pain medications were computed to morphine equivalents, only patients in the diclofenac group received less pain medications than the placebo group (P < 0.05). Proportion of patients with postoperative increase of creatinine level (20% and over) did not differ between placebo and drug groups. CONCLUSION: Non-steroidal anti-inflammatory drugs may be used for analgesia management post CABG surgery in selected patients. Diclofenac appears to have the best analgesic effects by reducing the morphine and other analgesic requirement postoperatively.     

Effective treatment of acute pain and related symptoms in elderly with herpes zoster

BACKGROUND: The incidence of herpes zoster increases with age. Immediate pain relief is required for prevention of postherpetic neuralgia (PHN) and also its related symptoms that worsen the general condition because acute herpetic pain often interferes with sleep, mood, and general activities in elderly patients. Nerve block is useful to relief acute pain and recommended for prevention of PHN. Tricyclic antidepressant drugs have antinoticeptive effect in acute pain in experimental models, in addition to its antidepressant effect. METHODS: Forty elderly patients with herpes zoster within 3 months after the onset underwent nerve blocks and received tricyclic antidepressant drugs. We assessed the effect of treatments and adverse effects. RESULTS: No significant adverse effects were found in elderly patients who had received nerve blocks and/or tricyclic antidepressant drugs. Alleviation of acute pain was obtained in more than 80% of patients, and in all patients depressive state and/or disturbance of the general condition were significantly improved. CONCLUSIONS: With careful technique and assessment of patients, both nerve block and tricyclic antidepressant drugs were beneficial and safe treatments in elderly patients with herpes zoster.     

Use of topiramate for spinal cord injury-related pain

BACKGROUND: Pain following spinal cord injury (SCI) has proved difficult to treat. Although the use of antiepileptic drugs to treat SCI-related pain has been studied previously, topiramate has not been investigated in this population. Our recent experience suggests that topiramate may be efficacious in the treatment of SCI-related pain. METHOD: Case Studies Findings: This report presents the clinical histories of two people with pain following SCI who reported beneficial effects of treatment with the new antiepileptic drug topiramate, even after failing treatment with standard analgesic medications. Topiramate was well tolerated in these patients. CONCLUSION: For post-SCI pain, topiramate appears to be an effective treatment in some patients. Based on the present anecdotal findings, larger controlled studies comparing topiramate with standard treatment for SCI-related pain are warranted.