No beneficial effect of intrathecal methylprednisolone acetate in postherpetic neuralgia patients.

BACKGROUND: High efficacy of intrathecal methylprednisolone acetate (MPA) with lidocaine has been reported in a large patient group suffering from intractable postherpetic neuralgia (PHN). Because the treatment effect was never independently confirmed and there are ongoing safety concerns, intrathecal MPA did not become standard care for intractable PHN. We report the results of a replication trial assessing pain relief and spinal cytokine/chemokine levels in PHN patients. METHODS: The number of patients to be included was determined using sequential analysis to limit patient exposure to the invasive experimental treatment. Patients were randomized to the treatment group receiving MPA 60 mg + lidocaine 60 mg or control group receiving lidocaine 60 mg only. Four injections at 7-day intervals were administered after cerebrospinal fluid (CSF) collection to measure cytokine/chemokine levels. Visual analogue scores for pain and the square allodynic area were collected during follow-up, with the primary end point set at 8 weeks follow-up. RESULTS: In total, 10 patients were included, of whom six were randomized to the treatment group. All six MPA-treated patients experienced a pain increase at 8 weeks, versus one of four patients in the control group. The square allodynic area increased in four of six MPA-treated patients versus one of four control patients. CSF interleukin-8 levels remained stable in the control group, but increased significantly after the first intrathecal MPA injection. The trial was stopped because of safety concerns and futility. CONCLUSION: Considering the absence of clinical benefits and the potential risks of the treatment, intrathecal administration of MPA is not recommended.

Sluder's neuralgia: a trigeminal autonomic cephalalgia?

The objective was to formulate distinctive criteria to substantiate our opinion that Sluder's neuralgia and cluster headache are two different clinical entities. A systematic review was carried out of all available, original literature on Sluder's neuralgia. Pain characteristics, periodicity and associated signs and symptoms were studied and listed according to frequency of appearance. Eleven articles on Sluder's neuralgia were evaluated. Several differences between Sluder's neuralgia and cluster headache became evident. Based on described symptoms, new criteria for Sluder's neuralgia could be formulated. Sluder's neuralgia and cluster headache could possibly be regarded as two different headache syndromes, and Sluder's neuralgia could be a trigeminal autonomic cephalalgia.

Action potential simulation (APS) in patients with fibromyalgia syndrome (FMS): a controlled single subject experimental design.

OBJECTIVES: Action potential simulation (APS) is becoming a popular method of pain reduction. Nevertheless, little is known about the efficacy of this relatively new treatment. The aim of this study was to investigate whether APS helps to reduce pain, improves patients' perception of daily functioning and social participation in patients with fibromyalgia syndrome (FMS). MATERIALS AND METHODS: Ten patients with FMS according to the American College of Rheumatology (ACR) criteria entered this double blind crossover single-case study. In a period of 20 weeks, the patients underwent two treatment periods of 4 weeks, one with verum and one with placebo, at random, in a double blind fashion. Outcome measures were evaluated on a weekly basis. Primary outcome measure was pain measured with the Fibromyalgia Impact Questionnaire (FIQ) questions 4 and 5, the number of tender points and the total tender point pain intensity score. Both visual inspection and statistical analysis were done to analyse the data from this single-subject design. RESULTS: Performing visual inspection and statistical analysis, no positive results of the APS treatment were found in this study. Remarkable is the fact that placebo APS had significantly better results than verum APS. CONCLUSIONS: In this single-case study with ten patients (all female), APS was not a helpful method to reduce pain, to improve patients' perception of daily functioning and social participation in patients with FMS.

The impact of chronic pain patients' psychotropic drug knowledge and warning labels on the decision whether to drive a car or not.

OBJECTIVE: The attitudes of patients towards driving a car while taking medication with psychotropic side effects is unclear. A growing number of patients use these psychotropic medicines on a daily basis, and this may interfere with their ability to drive a car. METHODS: By means of a survey, we examined attitudes towards driving while using psychotropic medicinal drugs and the effect of warning labels on the decision whether to drive a car or not in patients with chronic pain. RESULTS: Fifty-eight of 100 patients possessing a driver's license used psychotropic medication. Despite warning labels affixed on the packages that these drugs might impair driving ability, the majority (71%) of these patients continued driving a car. A point of concern is that 40% of these patients reported not to be more cautious in traffic after taking psychotropic drugs. CONCLUSION: The results of this survey indicate that drug warning labels applied by Dutch pharmacies do not significantly change attitudes towards driving a car in patients taking medicinal drugs with psychotropic side effects. Future road-safety campaigns should pay more attention to the impairing effects of psychotropic drugs on driving.

Processing capacity in chronic pain patients: a visual event-related potentials study.

Chronic pain may impair performance on attentional processing capacity tasks. In the present study, event-related potentials were recorded to examine whether pain patients show performance decrements on attentional processing capacity tasks due to shared resources by pain and attention or, alternatively, due to deficits in allocating attentional resources during pain. Fourteen chronic pain patients and thirty age and education matched healthy controls were investigated. An attentional capacity probe task was used in which the difficulty level was manipulated, resulting in an easy and a difficult condition, while task-irrelevant visual probes were presented. These probe-elicited P3 amplitudes were assumed to provide the most pure estimate of processing capacity since they are relatively free from target-related processes. Event-related potentials were recorded from the midline electrodes Fz, Cz, Pz, and Oz. For the behavioral measures, it was found that pain patients maintained a different speed-accuracy tradeoff. Pain patients showed faster reaction time responses and higher error rates compared to controls. No significant differences were found between pain patients and controls on the primary task. Pain patients differed from controls with respect to amplitudes elicited by task-irrelevant probe stimuli. For healthy controls, the expected decreased amplitude was found for probe stimuli in the difficult compared to the easy task. In contrast, the pain patients did not show decreased probe amplitudes with increasing task load. The data may imply that allocation of attentional resources is deficient in pain patients, instead of attentional capacity.

Effect of chronic nonmalignant pain on highway driving performance.

Most pain patients are treated in an outpatient setting and are engaged in daily activities including driving. Since several studies showed that cognitive functioning may be impaired in chronic nonmalignant pain, the question arises whether or not chronic nonmalignant pain affects driving performance. Therefore, the objective of the present study was to determine the effects of chronic nonmalignant pain on actual highway driving performance during normal traffic. Fourteen patients with chronic nonmalignant pain and 14 healthy controls, matched on age, educational level, and driving experience, participated in the study. Participants performed a standardized on-the-road driving test during normal traffic, on a primary highway. The primary parameter of the driving test is the Standard Deviation of Lateral Position (SDLP). In addition, driving-related skills (tracking, divided attention, and memory) were examined in the laboratory. Subjective assessments, such as pain intensity, and subjective driving quality, were rated on visual analogue scales. The results demonstrated that a subset of chronic nonmalignant pain patients had SDLPs that were higher than the matched healthy controls, indicating worse highway driving performance. Overall, there was a statistically significant difference in highway driving performance between the groups. Further, chronic nonmalignant pain patients rated their subjective driving quality to be normal, although their ratings were significantly lower than those of the healthy controls. No significant effects were found on the laboratory tests.

Acute and subchronic effects of amitriptyline on processing capacity in neuropathic pain patients using visual event-related potentials: preliminary findings.

RATIONALE: Little is known about the effects of low doses of amitriptyline, prescribed in the treatment of neuropathic pain, on attentional processing capacity. OBJECTIVES: Changes due to amitriptyline treatment on attentional processing capacity were investigated on behavioral measures and event-related brain potentials (ERPs) in six patients with neuropathic pain. MATERIALS AND METHODS: Patients were treated for 15 consecutive days with 25 mg nocturnally administered amitriptyline or placebo in a double-blind crossover randomized design. Measurements were carried out on day 1 and day 15 of each treatment period. An attentional capacity probe task was used in which the difficulty level was manipulated, resulting in an easy and a hard condition, while task-irrelevant visual probes were presented. During task performance, ERPs were measured from the midline electrodes Fz, Cz, Pz, and Oz. RESULTS: Amitriptyline increased reaction times (RTs) after acute but not after subchronic administration. ERP analyses showed that P3 amplitudes to the task stimuli were not affected by amitriptyline in either treatment phase. Moreover, P3 amplitudes to the probes were increased in the easy compared to the hard task condition after subchronic amitriptyline treatment, indicating beneficial effects of repeated amitriptyline administration. In contrast, acute amitriptyline administration did reduce an earlier visual evoked potential, N1, preceding the P3 component. CONCLUSIONS: The results suggest that amitriptyline, even at low dosages of 25 mg, affects performance after acute administration in chronic neuropathic pain patients. After 2 weeks of treatment, performance appears to be unaffected. No deficits in processing capacity due to amitriptyline treatment were found.

[Treatment of patients with herpes zoster by epidural injection of steroids and local anaesthetics: less pain after 1 month, but no effect on long-term postherpetic neuralgia--a randomised trial]. / Behandeling van patiënten met herpes zoster door epidurale injectie van steroïden en lokale anesthetica: minder pijn na 1 maand, maar geen effect op langdurige postherpetische pijn; gerandomiseerd onderzoek.

OBJECTIVE: To assess the effectiveness of a single epidural injection of steroids and local anaesthetics, as a supplement to the standard treatment, for the prevention ofpostherpetic neuralgia in older patients with herpes zoster. DESIGN: Open randomised trial. METHOD: In the period September 2001-February 2004, 598 patients, aged > 50 years, with acute herpes zoster (rash for < 7 days) below dermatome C6, were randomly assigned to receive either standard therapy (oral antiviral agents and analgesics) alone or standard therapy plus an additional single epidural injection of 80 mg methylprednisolone and 10 mg bupivacaine. The primary endpoint was the proportion of patients with zoster-associated pain one month after inclusion. The presence and severity of zoster-associated pain at other time points were secondary endpoints. RESULTS: At one month, pain was reported by 137 (48%) patients in the injection group versus 164 (58%) in the control group (relative risk; RR: 0.83; 95% CI: 0.71-0.97; p = 0.02). After three months, these values were 58 (21%) and 63 (24%), respectively (RR: 0.89; 95% CI: 0.65-1-21; p = 0.47), and at 6 months: 39 (15%) and 44 (17%) (RR: 0.85; 95% CI: 0.57-1-13; p = 0.43). No subgroups were detectable in which the relative risk for pain at one month after inclusion substantially differed from the overall estimate. At one month, the median severity of pain in the injection group was 2 (on a 100-points scale) versus 6 in the control group (p = 0.02). At later follow-up, there was no longer any statistically significant difference in the severity of pain between the two groups. No patient had major adverse events related to the epidural injection. CONCLUSION: A single epidural injection of steroids and local anaesthetics in the acute phase of herpes zoster resulted in a modest decrease in zoster-associated pain in the first month. This treatment did not, however, prevent long-term postherpetic neuralgia.