Medical and pharmacologic management of upper extremity neuropathic pain syndromes

Pharmacological management of persistent pain in older persons

Drugs without a strong evidence base and outside of recommendations are too often prescribed for older adults. Established guidelines such as Beers criteria have identified both specific medications and certain drug classes as inappropriate for older adults, primarily due to adverse effects. Age-related physiological changes in distribution, metabolism, and elimination often alter the effects of pharmacotherapies in older adults. When designing a therapeutic program, all elements contributing to the pathophysiology of painful conditions should be considered, as well as the mechanisms of action of analgesic drug classes. Both appropriate and inappropriate medications for older adults are detailed herein, as well as their contraindications and potential drug-drug or drug-disease interactions. The number needed to treat (NNT) can be useful in considering efficacy, while the safety of a pharmacotherapy is indicated by the calculated number needed to harm (NNH). The NNT is a measure describing the number of patients who require treatment for every 1 who reaches the therapeutic goal, and the NNH describes the number of participants who manifest side effects; these can further be segregated into numbers who withdraw from studies due to intolerable side effects. These parameters, along with a patient's comorbidities and concomitant medications, should be considered when selecting an analgesic and dose regimen. In addition, practitioners should avoid prescribing multiple-drug therapies that have overlapping pharmacodynamics or that may have an adverse pharmacokinetic interaction.

Pharmacological management of neuropathic pain in older adults: an update on peripherally and centrally acting agents

The burden of neuropathic pain in older adults is great and the practitioner is challenged to reduce symptoms and improve quality of life. Many common neuropathic pain syndromes are more prevalent in the older population, and older adults also carry greater sensitivity to certain side effects. The health care professional should have a thorough familiarity with all medications available to treat this difficult group of disorders.

The Challenge to Manage Reflex Sympathetic Dystrophy/Complex Regional Pain Syndrome

The challenge to understand reflex sympathetic dystrophy/complex regional pain syndrome may require a better understanding of the complex relationship between the central and peripheral nervous systems. There is no comprehensive hypothesis that clearly explains the etiology and no uniformly successful treatment method. This brief summary of the challenge reviews some of what is known, hypothesizes a possible etiologic mechanism, and proposes 10 common-sense principles for management that recognizes the handicap of limited knowledge.

Randomised controlled trial of gabapentin in Complex Regional Pain Syndrome type 1 [ISRCTN84121379]

Background

Complex Regional Pain Syndrome type one (CRPS I) or formerly Reflex Sympathetic Dystrophy (RSD) is a disabling syndrome, in which a painful limb is accompanied by varying symptoms. Neuropathic pain is a prominent feature of CRPS I, and is often refractory to treatment. Since gabapentin is an anticonvulsant with a proven analgesic effect in various neuropathic pain syndromes, we sought to study the efficacy of the anticonvulsant gabapentin as treatment for pain in patients with CRPS I.

Methods

We did a randomized double blind placebo controlled crossover study with two three-weeks treatment periods with gabapentin and placebo separated by a two-weeks washout period. Patients started at random with gabapentin or placebo, which was administered in identical capsules three times daily. We included 58 patients with CRPS type 1.

Results

Patients reported significant pain relief in favor of gabapentin in the first period. Therapy effect in the second period was less; finally resulting in no significant effect combining results of both periods. The CRPS patients had sensory deficits at baseline. We found that this sensory deficit was significantly reversed in gabapentin users in comparison to placebo users.

Conclusions

Gabapentin had a mild effect on pain in CRPS I. It significantly reduced the sensory deficit in the affected limb. A subpopulation of CRPS patients may benefit from gabapentin.

Tramadol--present and future

The atypical opioid, tramadol, has recently been introduced into Australia and New Zealand. Tramadol's efficacy in a wide range of acute and chronic pain states, its multi-formulation availability, and its low serious side-effect potential at high doses and in prolonged therapy, combine to bestow on it a user-friendly profile, for short- and long-term use in hospitals and communities. This paper reviews the following: its formulation and routes of administration; its unique enantiomeric biochemistry and metabolism; its triple mechanisms of action; its pharmacokinetics and pharmacodynamics; its analgesic efficacy compared with other opioids; the indications for its clinical use in a variety of acute and chronic (including cancer) painful states; its specific use in the elderly, in paediatric and in obstetric patients; its adverse event (including drug interaction) and safety profile; its advantages in terms of its relative lack of respiratory depression, major organ toxicity and histamine release, and dependence and abuse potential. The review looks at new uses for this drug and what can be expected in this area in the future.

Use of gabapentin in the treatment of neuropathic pain

OBJECTIVE

To evaluate the role of gabapentin for the treatment of neuropathic pain.

DATA SOURCES

Clinical literature was identified through MEDLINE (from 1990 to October 1999). Key search terms were gabapentin and pain.

DATA SYNTHESIS

Neuropathic pain can be a problematic, chronic syndrome that is frequently refractory to current drug treatments. Gabapentin is a newer generation antiepileptic drug that is commonly used in treatment of neuropathic pain. An evaluation of clinical trials using gabapentin to treat neuropathic pain was performed.

CONCLUSIONS

Gabapentin appears to be effective in treating various neuropathic pain disorders. Gabapentin may have advantages over current therapies, such as a favorable safety profile and lack of drug interactions; however, cost issues and limited experience may limit the use of gabapentin as a first-line option.

Complex regional pain syndrome (CRPS) with resistance to local anesthetic block: a case report

We present a case of complex regional pain syndrome (CRPS) Type 1 in a 12-year-old girl. The patient did not respond to the usual therapeutic modalities used to treat CRPS, including physical therapy, lumbar sympathetic block, epidural local anesthetic block, intravenous lidocaine infusion, or other oral medications. Of note is the fact that, during epidural block, the patient demonstrated a resistance to local anesthetic neural blockade in the area of the body involved with the pain problem. The mechanism of this resistance could be related to the changes in the dorsal horn cells of the spinal cord, secondary to activation of N-methyl-D-aspartate receptors, which may play a role in the pathophysiology of this pain syndrome.

Effectiveness of Tizanidine in Neuropathic Pain: An Open-Label Study

The purpose of this research trial is to assess the effectiveness and tolerability of tizanidine in neuropathic pain. In an open-label study, patients with neuropathic pain received 1 to 4 mg of tizanidine once daily for 7 days, followed by weekly dose escalation of 2 to 8 mg to his/her effective or maximum tolerated dose or a maximum of 36 mg over an 8-week period. Treatment effects were assessed, using average weekly pain scores as well as biweekly scores for patient global assessment of pain relief, the neuropathic pain scale, and wisconsin brief pain inventory. Frequency and severity of adverse events were examined also. Twenty-three patients were enrolled. The mean average weekly pain score at baseline was 6.9, which decreased by 1.7 points at the end of week 8 to 5.2 (p < or =.01). A total of 15 patients (68%) reported that their pain relief was improved or much improved with tizanidine therapy, and 2 of these patients became completely pain-free. The following neuropathic pain qualities were significantly lower at week 8 compared with baseline: intense, sharp, hot, dull, cold, sensitive, unpleasant, and deep pain. There was a significant decline in pain quantity and interference of pain on quality of life from baseline to week 8. The mean effective or maximum tolerated dose was 23 mg/day (range 6 to 36 mg/day). Side effects consisted primarily of dizziness/lightheadedness (52%), drowsiness (48%), fatigue/weakness (43%), dry mouth (39%), gastrointestinal upset (30%), and sleep difficulty (22%). One patient developed significant elevation in liver function tests (LFTS) With symptoms at week 4. Tizanidine therapy was discontinued. LFTS returned to normal in 3 weeks. Tizanidine might be an effective treatment for neuropathic pain, offering an alternative for patients poorly responsive to other medications. A larger, randomized placebo-controlled trial is recommended. In addition, comparative studies with alternative agents should be sought.