Total Pain Intensity Research Articles

The influence of brushing force and stroking velocity on dynamic mechanical allodynia in patients with peripheral neuropathy

Recently we demonstrated brush-evoked allodynia to be a partially graded phenomenon since increased brushing length and number of strokes significantly increased the brush-evoked pain intensity. In this study the influence of stroking velocity and brushing force on dynamic mechanical allodynia was examined in 16 patients with peripheral neuropathy. Brush-evoked allodynia was induced by lightly stroking 60 mm of the skin twice with a 16 mm wide brush while varying stroking velocity (10, 20, 30 mm/s) and brushing force (10, 20, 40 g). Intensity and duration of brush-evoked allodynia was recorded using a computerized visual analogue scale. The total brush-evoked pain intensity, including painful aftersensation was calculated as the area under the curve. Significantly increased total brush-evoked pain intensity was demonstrated with lower stroking velocity ( P < 0.001) and higher brushing force ( P < 0.05). Higher maximum pain intensity was reported with higher brushing force. In conclusion, our findings demonstrated a significant relationship between the total brush-evoked pain intensity and stroking velocity as well as brushing force. Together with previously accumulated data these results substantiate the usefulness of this semi-quantitative assessment method in longitudinal studies on dynamic mechanical allodynia.

Pregabalin and gabapentin in matched patients with peripheral neuropathic pain in routine medical practice in a primary care setting: Findings from a cost-consequences analysis in a nested case-control study

Background: Pregabalin and gabapentin are marketed to treat peripheral neuropathic pain, but head-to-head comparison is lacking. Objectives: The aims of this work were to compare the effects of pregabalin and gabapentin on different patient-reported health outcomes and to analyze health care and nonhealth-care resource consumption and their related costs among patients treated for peripheral neuropathic pain in primary medical care. Methods: A cost-consequences comparison in subjects with refractory (suboptimal response to ≥1 previous analgesic treatment for >6 months) chronic peripheral neuropathic pain was carried out using data extracted from two 12-week, observational, prospective studies in primary medical care. Patients were eligible if they were aged ≥18 years, had a score of ≥4 on the Douleur Neuropathique 4 questionnaire, and were able to complete health questionnaires written in Spanish. A nested-paired case-control design was chosen to perform the comparison with 2 controls (pregabalin) per case (gabapentin) matched by age, sex, peripheral neuropathic pain condition, time since diagnosis, number of previous treatments, pain intensity, depressive and anxiety symptom scores, and health state. Adult subjects with refractory chronic pain because of diabetic neuropathy, postherpetic or trigeminal neuralgias, or cervical or lumbosacral radiculopathies were included. Epidemiologic statistical methods were applied for comparing health effects (pain intensity, sleep, anxiety and depressive symptoms, disability, and health state), resources utilization, and related cost variations after 12 weeks. Indirect costs were measured by means of lost-workday equivalent calculations multiplied by the mean national daily salary. Results: Analysis included 44 patients treated with gabapentin (cases) and 88 patients treated with pregabalin (controls) who were matched for age, sex, and other parameters. The mean (SD) gabapentin and pregabalin doses were 1263 (540) and 202 (119) mg/d, respectively. Although there was a greater reduction in last-week mean pain intensity with pregabalin (visual analog scale: 39.1 [22.5] vs 28.0 [22.2] mm; P = 0.008), as well as more patients with a ≥50% reduction in pain rate (60.9% vs 40.5%; P = 0.029), there were no significant differences between groups for sensory, affective, total, or present pain intensity. The significantly higher drug cost associated with pregabalin was offset by a greater reduction in productivity costs compared with gabapentin, yielding similar cost reduction (−€1254 [1479] vs −€1384 [2874], respectively; P = NS). Conclusion: Pregabalin appeared to be associated with greater reduction in mean weekly intensity of pain, but there were no significant differences in cost.

Single dose oral codeine, as a single agent, for acute postoperative pain in adults

Codeine is an opioid metabolised to active analgesic compounds, including morphine. It is widely available by prescription, and combination drugs including low doses of codeine are commonly available without prescription. To assess the efficacy, the time to onset of analgesia, the time to use of rescue medication and any associated adverse events of single dose oral codeine in acute postoperative pain. We searched CENTRAL, MEDLINE, EMBASE and PubMed to November 2009. Single oral dose, randomised, double-blind, placebo-controlled trials of codeine for relief of established moderate to severe postoperative pain in adults. Studies were assessed for methodological quality and data independently extracted by two review authors. Summed total pain relief (TOTPAR) or pain intensity difference (SPID) over 4 to 6 hours were used to calculate the number of participants achieving at least 50% pain relief, which were used to calculate, with 95% confidence intervals, the relative benefit compared to placebo, and the number needed to treat (NNT) for one participant to experience at least 50% pain relief over 4 to 6 hours. Numbers using rescue medication over specified time periods, and time to use of rescue medication, were sought as additional measures of efficacy. Data on adverse events and withdrawals were collected. Thirty-five studies were included (1223 participants received codeine 60 mg, 27 codeine 90 mg, and 1252 placebo). Combining all types of surgery (33 studies, 2411 participants), codeine 60 mg had an NNT of at least 50% pain relief over 4 to 6 hours of 12 (8.4 to 18) compared with placebo. At least 50% pain relief was achieved by 26% on codeine 60 mg and 17% on placebo.Following dental surgery the NNT was 21 (12 to 96) (15 studies, 1146 participants), and following other types of surgery the NNT was 6.8 (4.6 to 13) (18 studies, 1265 participants). The NNT to prevent use of rescue medication within 4 to 6 hours was 11 (6.3 to 50) (11 studies, 765 participants, mostly non-dental); the mean time to its use was 2.7 hours with codeine and 2.0 hours with placebo. More participants experienced adverse events with codeine 60 mg than placebo; the difference was not significant and none were serious. Two adverse event withdrawals occurred with placebo. Single dose codeine 60 mg provides good analgesia to few individuals, and does not compare favourably with commonly used alternatives such as paracetamol, NSAIDs and their combinations with codeine, especially after dental surgery; the large difference between dental and other surgery was unexpected. Higher doses were not evaluated.

Relationships among alexithymia and pain intensity, pain interference, and vitality in persons with neuromuscular disease: Considering the effect of negative affectivity

Alexithymia, the inability to identify or label emotions, has been shown to be associated with pain in patients with a number of chronic pain conditions. We sought to: (1) replicate this association in samples of persons with chronic pain secondary to neuromuscular disease, (2) extend this finding to other important pain-related measures, and (3) to determine whether relationships among alexithymia and study variables existed after controlling for negative affect. One hundred and twenty-nine individuals with muscular dystrophy and chronic pain were administered measures of alexithymia (Toronto Alexithymia Scale, TAS-20), pain intensity (0–10 NRS), pain interference (Brief Pain Inventory Interference scale), mental health (SF-36 Mental Health scale; as a proxy measure of negative affect) and vitality (SF-36 Vitality scale). Higher TAS scores were associated significantly with higher pain intensity and interference, and less vitality. Although the strengths of these associations were reduced when mental health was used as a control, the associations between the Difficulty Identifying Feelings scale and vitality, and the Externally Oriented Thinking and Total TAS scales and pain intensity remained statistically significant. The findings replicate and extend previous findings concerning the associations between alexithymia and important pain-related variables in a sample of persons with chronic pain and neuromuscular disease. Future research is needed to determine the extent to which the associations are due to (1) a possible causal effect of alexithymia on patient functioning that is mediated via its effects on negative affect or (2) the possibility that alexithymia/outcome relationships reflect response bias caused by general negative affectivity.

Effects of Intramuscular Anesthesia on the Expression of Primary and Referred Pain Induced by Intramuscular Injection of Hypertonic Saline

Intramuscular injection of hypertonic saline produces pain in the belly of the injected muscle (primary pain) and, often, pain that projects distally (referred pain). While it is known that referred pain can be induced during complete sensory block of the distal site, there is little evidence as to whether the perception of referred pain depends on ongoing input from the primary stimulus. We assessed whether blocking the noxious input following the induction of pain blocks the primary but not the referred pain. A cannula was inserted into the tibialis anterior muscle in 15 subjects (8 male, 7 female). In a quasi-random crossover design conducted over 2 experimental sessions, each subject received a bolus intramuscular injection of .5 mL of 5% hypertonic saline, followed 90 seconds later by either: A) A second bolus injection or; B) An injection of 2 mL lignocaine through the same cannula. Protocol A was followed 60 seconds later by either a sham injection or an injection of lignocaine, while protocol B was followed 60 seconds later by either a sham injection or an injection of hypertonic saline. Subjects mapped the areas of primary and referred pain, and rated the intensities at these sites every 30 seconds until the cessation of pain. In all subjects, the area and intensity of primary pain rapidly disappeared within 7.5 minutes of intramuscular lignocaine injection (P < .02 relative to the nonanesthesia condition). With the exception of 2 subjects, in whom the referred pain continued in the absence of primary pain, the referred pain declined in parallel with local pain: the mean total pain intensity declined by 74% in both regions. We conclude that the maintenance of referred muscle pain usually depends on ongoing noxious inputs from the site of primary muscle pain. Referred pain is a significant clinical problem, and commonly occurs with pain originating in muscle but not from skin. It is important to know the primary source of the pain so that treatment can be directed to this site rather to the site of referral.

Assessing pain behaviors in healthy subjects using the Critical-Care Pain Observation Tool (CPOT): a pilot study

The critical care pain observation tool (CPOT) is the only valid pain assessment tool used in critical care with patients who cannot communicate verbally. However, the predictive value of the CPOT has not been studied in controlled experimental settings. The goal of this study was to determine the strength of the relationship between verbal pain ratings and the pain behaviour (score obtained via the CPOT) in healthy subjects. 18 subjects participated in the study (mean age = 37.8 years). All subjects underwent a two minutes noxious cold pressor test (CPT) at 7°C. Verbal pain ratings were obtained with a numerical pain scale (0-100) while pain behaviours were recorded by video camera. Afterwards, two independent evaluators quantified pain behaviours using the CPOT. Simple regression analysis between pain intensity and the CPOT score enabled us to obtain the predictive value of the CPOT. We found an excellent interrater reliability (ICC = 0.963, 95%CI [0.904-0.986]). We observed a significant relationship between the total CPOT score and pain intensity during the CPT (r = 0.52, p = 0.028). Although this relationship is moderate, it still indicates that subjects reporting greatest pain intensity showed more pain behaviour. Furthermore, no sex differences were observed, suggesting that men and women tend to have similar pain behaviours. This pilot study confirms the relationship between pain behaviours and pain intensity ratings in healthy subjects. Furthermore, this study supports the use of the CPOT in clinical settings and confirms that a high CPOT score is correlated with moderate to high levels of pain intensity.

Influence of heterotopic noxious conditioning stimulation on spontaneous pain and dynamic mechanical allodynia in central post-stroke pain patients

In 10 patients with central post-stroke pain (CPSP), the influence of ischemia-induced heterotopic noxious conditioning stimulation (HNCS) on the intensity of spontaneous ongoing- and brush-evoked pain was examined. In addition, the modulating effect of ongoing pain and HNCS on pain sensitivity in a remote pain-free area was explored. A semi-quantitative brushing technique was employed in combination with a computerized visual analogue scale (VAS) to monitor the allodynic percept over time, by calculating the area under the VAS curve as the total brush-evoked pain intensity. Heat- and pressure pain thresholds and sensitivity to suprathreshold heat- and pressure pain in the pain-free area were assessed before and during HNCS. No significant alterations of ongoing- or brush-evoked pain were found during HNCS, although 6 of 10 patients rated a reduction of about 50% of the brush-evoked pain. At baseline significantly increased pressure pain sensitivity (threshold P < 0.05; suprathreshold P = 0.05) were demonstrated in patients compared to controls. During HNCS, higher pressure pain thresholds were demonstrated in patients and controls alike ( P < 0.001), whereas in controls only decreased sensitivity to suprathreshold pressure pain was found ( P < 0.05). Lack of influence from HNCS on ongoing- and brush-evoked pain on a group level, indicates inability of modulation from endogenous pain controlling systems on nociceptive activity generated in the brain. Increased pressure pain sensitivity at baseline suggests alteration in corticofugal control of nociceptive sensitivity due to the brain lesion, whereas patients during HNCS seemed to activate modulatory systems interacting with nociceptive input from the spinal level equal to controls.

Efficacy and tolerability of tapentadol immediate release and oxycodone HCl immediate release in patients awaiting primary joint replacement surgery for end-stage joint disease: A 10-day, phase III, randomized, double-blind, active- and placebo-controlled study

Objectives: The primary objective of this study was to assess the efficacy and tolerability of tapentadol immediate release (IR) in patients who were candidates for joint replacement surgery due to end-stage joint disease. A secondary objective was to compare tapentadol IR with oxycodone HCl IR with respect to efficacy and prespecified tolerability end points. Methods: This 10-day, Phase III, randomized, double-blind, active- and placebo-controlled study compared the efficacy and tolerability of tapentadol IR, oxycodone HCl IR, and placebo in patients with uncontrolled osteoarthritis pain who were candidates for primary replacement of the hip or knee as a result of end-stage degenerative joint disease. Patients received tapentadol IR 50 mg, tapentadol IR 75 mg, oxycodone HCl IR 10 mg, or placebo every 4 to 6 hours during waking hours. The primary end point was the sum of pain intensity difference (SPID) over 5 days. Secondary efficacy end points included 2- and 10-day SPID; 2-, 5-, and 10-day total pain relief (TOTPAR); and the sum of total pain relief and pain intensity difference (SPRID). Prespecified noninferiority comparisons with oxycodone HCl IR were performed with respect to efficacy (based on 5-day SPID) and tolerability (based on incidence of the reported adverse events (AEs) of nausea and/or vomiting and constipation). Results: Of 666 patients originally enrolled, 659 were included in the efficacy analysis (51% male; 91% white; mean age, 61.2 years; mean weight, 97 kg). Five-day SPID was significantly lower in those treated with tapentadol IR (tapentadol IR 50 mg: least squares mean difference [LSMD] = 101.2 [95% CI, 54.58- 147.89]; tapentadol IR 75 mg: LSMD = 97.5 [95% CI, 51.81-143.26]) or oxycodone HCl IR (LSMD = 111.9 [95% CI, 66.49-157.38]) (all, P < 0.001). Tapentadol IR 50 and 75 mg and oxycodone HCl IR 10 mg were associated with significant reductions in pain intensity compared with placebo, based on 2- and 10-day SPID and 2-, 5-, and 10-day TOTPAR and SPRID (all, P < 0.001). The efficacy of tapentadol IR 50 and 75 mg was noninferior to that of oxycodone HCl IR 10 mg; however, the incidence of selected gastrointestinal AEs (nausea, vomiting, and constipation) was significantly lower for both doses of tapentadol IR compared with oxycodone HCl IR 10 mg (nominal P < 0.001). The odds ratios for nausea and/or vomiting for tapentadol IR 50 and 75 mg relative to oxycodone HCl IR 10 mg were 0.21 (95% CI, 0.128-0.339) and 0.32 (95% CI, 0.204-0.501), respectively; for constipation, the corresponding odds ratios were 0.13 (95% CI, 0.057-0.302) and 0.20 (95% CI, 0.098-0.398). Rates of treatment discontinuation were 18% (28/157) in the tapentadol IR 50-mg group, 26% (43/168) in the tapentadol IR 75-mg group, 35% (60/172) in the oxycodone HCl IR 10-mg group, and 10% (17/169) in the placebo group. In a post hoc analysis, tapentadol IR 50 mg was associated with a significantly lower incidence of treatment discontinuation than was oxycodone HCl IR 10 mg ( P < 0.001). Conclusions: In these patients with uncontrolled osteoarthritis pain who were awaiting joint replacement surgery, tapentadol IR 50 and 75 mg were associated with analgesia that was noninferior to that provided by oxycodone HCl IR 10 mg. Tapentadol treatment was associated with improved gastrointestinal tolerability. ClinicalTrials.gov Identifier: NCT00361582.

Clinical trial: the glucagon‐like peptide‐1 analogue ROSE‐010 for management of acute pain in patients with irritable bowel syndrome: a randomized, placebo‐controlled, double‐blind study

There is currently no treatment available to manage acute pain attacks in IBS patients regardless of subtype. To evaluate efficacy and safety of the GLP-1 analogue ROSE-010 in patients with irritable bowel syndrome (IBS) through a randomized, double-blind, placebo-controlled study. Eligible patients (n = 166) meeting Rome II criteria were randomly assigned to receive single subcutaneous injections of ROSE-010 100 microg, 300 microg and placebo in a cross-over design. Safety was assessed from spontaneously reported adverse events and measurement of vital signs. Patient-rated pain relief and intensity were measured on a 100-mm visual analogue scale. The primary efficacy variable was proportion of patients with >50% maximum total pain relief response from 10 to 60 min after treatment. Secondary endpoints included the maximum summed pain intensity difference, time to meaningful pain relief and patient ratings of satisfaction with treatment. Twice as many patients were responders in the primary efficacy endpoint after both ROSE-010 injections compared to placebo (24%P = 0.011, 23%P = 0.005, and 12% after 300 microg, 100 microg and placebo injections, respectively). Similar results were obtained for the proportion of patients with total pain intensity response. Times to meaningful and total pain relief were shorter for both doses of ROSE-010 compared with placebo. Compared with placebo, more patients (P < 0.05) were satisfied with ROSE-010 and considered ROSE-010 better than previous IBS medications used. ROSE-010 was well tolerated and provided fast and effective relief of acute pain attacks on demand in IBS patients.

Congenital hypothyroidism alters formalin-induced pain response in neonatal rats

The present study designed to investigate the development of nociceptive circuits upon formalin-induced pain in congenital hypothyroid pups during the first three postnatal weeks. Following induction of maternal hypothyroidism, the offspring pups were received right intraplantar injection of different formalin concentrations at 7, 15, and 23 days of age. Significant reduction in weight gain was observed in PTU-treated offspring from postnatal days 15 up to 23 (P<0.001). No difference was observed between normal and hypothyroid PND7 pups in total pain intensity score with 0.3% solution of formalin. However, normal pups showed higher total pain score (P<0.01) during the first phase of 1% formalin injection. PND15 normal pups showed a biphasic pain response with a concentration of 2% formalin injection. Obvious persistence of higher pain intensity was observed in hypothyroid pups after interphase through the 2nd phase (P2) and recovery phase (P3), (P<0.001). PND23 hypothyroid rats showed slightly biphasic pattern of pain behavior with persistence of lower pain intensity during P2 (2.5% formalin, P<0.05), (10% formalin, P<0.001) without any further decline during P3 (P<0.01, P<0.001 respectively). In general, the number of flexes+shakes in hypothyroid pups was higher than normal pups in both the early and late phases of the test. Licking activity was intensively expressed only in normal pups during phase 2 at the age of 23 days. In contrast to acute pain, hypothyroidism results to pain hypersensitivity in two weeks old rats whereas weaned rats were hyposensitive to tonic nociceptive stimulation without showing the subsequent recovery phase.

Assessment of motion in the cervico-thoracic spine in patients with subacute whiplash-associated disorders

To investigate the distribution of segmental flexion mobility in the cervico-thoracic spine of men and women with whiplash-associated disorders. The study also assesses the relationship between cervical mobility and segmental flexion mobility, and whether hypomobility in C7-T1 is associated with neck pain and weakness in the hands. Finally, the study investigates the impact of fear of movement/(re)injury and pain intensity on cervical mobility. The data in this longitudinal study was obtained from a previous trial on 47 patients. Assessments were performed at baseline and 3 and 9 months following randomization using a cervical range of motion instrument, the cervico-thoracic ratio, a Grippit, a visual analogue scale, a Painmatcher, and the Tampa Scale for Kinesiophobia. Women exhibited hypomobility in C7-T1. There was no significant association between the 2 cervical measurement techniques. The correlation between flexion mobility in C7-T1 and grip strength was weak but significant (r=-0.3) (p<0.05). There was also a weak but significant negative correlation between total cervical mobility and neck pain intensity. No significant correlation was found between fear of movement/(re)injury and cervical mobility. Women with whiplash-associated disorders seem to exhibit flexion hypomobility in C7-T1. The flexion mobility in C7-T1 was weakly, but significantly, correlated with grip strength, but was not shown to predict neck pain. Neck pain may give rise to restricted range of motion.

A Multicentre, Randomised, Double-Blind Study Comparing the??Efficacy and Tolerability of Intramuscular Dexketoprofen versus Diclofenac in the Symptomatic Treatment of Acute Low Back Pain

Low back pain is an important medical problem in Western industrialised countries. NSAIDs are one of the main options for symptomatic pain relief in the early management of this painful condition. Dexketoprofen is an NSAID belonging to the arylpropionic acid group that has demonstrated good analgesic efficacy and a good safety profile in different acute and chronic painful conditions. A randomised, double-blind, parallel, active controlled, multicentre study that included 370 outpatients with acute low back pain was conducted to compare the analgesic efficacy of dexketoprofen 50mg twice daily versus diclofenac 75mg twice daily administered intramuscularly for 2 days. Efficacy outcomes were assessment of pain intensity (PI) measured on a visual analogue scale, total PI scores from baseline to 6 hours after the first-dose administration (primary efficacy endpoint; SAPID(0-6)), score on a physical disability scale using the Roland Disability Questionnaire (RDQ), and use of rescue medication. Tolerability and safety were also assessed as secondary variables. The adjusted mean (SAPID(0-6)) scores were very similar, 117.3 mm/h with dexketoprofen and 114.7 mm/h with diclofenac. The adjusted ratio of means was 1.023 and the lower 95% confidence limit was 0.81, demonstrating non-inferiority of dexketoprofen (defined by a lower limit of the 95% CI >0.80) in comparison with diclofenac (per-protocol analysis). The median change in the RDQ was -6 points for both groups (p = 0.69), showing an overall improvement on the disability scale. No significant differences between groups were observed regarding the percentage of patients needing rescue medication or in the mean values of pain after repeated doses (SAPID(0-last)). Dexketoprofen was well tolerated, with a reported incidence of adverse events similar to that of diclofenac. No serious adverse events were reported in either treatment group. From the results of this study it can be concluded that dexketoprofen 50mg administered twice daily intramuscularly provides a clinically relevant analgesic effect with good tolerability after single and repeated doses in patients with acute severe low back pain.

On the repeatability of brush-evoked allodynia using a novel semi-quantitative method in patients with peripheral neuropathic pain

Using a semi-quantitative method the repeatability of brush-evoked allodynia was examined within and between days in nine patients with spontaneous ongoing pain and dynamic mechanical allodynia due to peripheral neuropathy. In addition, the relationship between the intensity of spontaneous ongoing pain and the total brush-evoked pain intensity was addressed. The brush stimulus was applied in the innervation territory of the lesioned nervous structure by lightly stroking 60 mm of the skin four times with an 8 mm wide brush. Using a computerized visual analogue scale the patients continuously rated the intensity and duration of brush-evoked allodynia and the total brush-evoked pain intensity was calculated as the area under the curve. The patients were examined 4 days during one month, i.e. at day 1, 3, 28 and 30 and each study day the stimulus was repeated four times with an inter-stimulus interval of 10 min. The variation between repeated assessments was analyzed using the intraclass correlation coefficient and the total brush-evoked pain intensity within days ranged from 0.89 to 0.95 (“very good repeatability”) and between days from 0.77 to 0.97 (“very good repeatability”). A significant positive correlation was demonstrated between the mean intensity of spontaneous ongoing pain and the mean total brush-evoked pain intensity ( r s = 0.68, P < 0.042, “a moderate to good correlation”).

Reliability and validity of the Turkish version short-form McGill pain questionnaire in patients with rheumatoid arthritis

The translation of existing pain measurement scales is considered important in producing internationally comparable measures for evidence based practice. In measuring the pain experience, the short-form of McGill's pain questionnaire (SF-MPQ) is one of the most widely used and translated instruments. The purpose of this study was to examine whether the Turkish version of the SF-MPQ is a valid and reliable tool to assess pain and to be used as a clinical and research instrument. Translation retranslation of the English version of the SF-MPQ was done blindly and independently by four individuals and adapted by a team. Eighty-nine rheumatological patients awaiting control by a rheumatologist were assessed by the Turkish version of the SF-MPQ in the morning and in the afternoon of the same day. Internal consistency was found adequate at both assessments with Cronbach's alpha 0.705 for test and 0.713 for retest. For reliability of the total, sensory, affective, and evaluative total pain intensity, high intraclass correlations were demonstrated (0.891, 0.868, 0.716, and 0.796, respectively). Correlation of total, sensory and affective score with the numeric rating scale was tested for construct validity demonstrating r = 0.637 (p < 0.001) for test and r = 0.700 (p < 0.001) for retest. Correlation with erythrocycte sedimentation rates for concurrent validity was found to be r = 0.518 (p < 0.001) for test and r = 0.497 (p < 0.001) for retest. The results of this study indicate that the Turkish version of the SF-MPQ is a reliable and valid instrument for the measurement of pain in Turkish speaking patients with rheumatoid arthritis.

Heterotopic noxious conditioning stimulation (HNCS) reduced the intensity of spontaneous pain, but not of allodynia in painful peripheral neuropathy

In 15 patients with painful peripheral neuropathy and dynamic mechanical allodynia, the influence of spontaneous ongoing neuropathic pain on pain sensitivity in a remote pain-free area was examined, as was the influence of ischemia-induced heterotopic noxious conditioning stimulation (HNCS) on the intensity of ongoing pain and brush-evoked allodynia. In addition, the modulating effect of HNCS on pain sensitivity in a pain-free area was investigated. Pain thresholds to pressure and heat as well as the sensitivity to suprathreshold pressure- and heat pain were assessed in the pain-free area. Dynamic mechanical allodynia was induced by a recently developed semi-quantitative brushing technique and the patients continuously rated the intensity of the allodynia using a computerized visual analogue scale (VAS). The total brush-evoked pain intensity was calculated as the area under the VAS curve. At baseline, no significant difference in pain sensitivity was found between patients and their healthy controls in the pain-free area, indicating a lack of activation of pain modulatory systems from the spontaneous pain. Compared to baseline, the patients rated the ongoing neuropathic pain intensity significantly lower during the HNCS-procedure ( p < 0.05). In contrast, there was no influence from HNCS on the total brush-evoked pain intensity. In the pain-free area higher pressure pain thresholds were demonstrated during conditioning stimulation in patients and controls alike ( p < 0.01). In controls only, a significantly higher heat pain threshold was found during the HNCS-procedure ( p < 0.01). The main finding of the present study was that HNCS altered differentially spontaneous and brush-provoked pain in patients with painful peripheral neuropathy.

Dynamic mechanical allodynia: On the relationship between temporo-spatial stimulus parameters and evoked pain in patients with peripheral neuropathy

The relationship between temporo-spatial stimulus parameters and evoked pain intensity as well as duration was examined in patients with peripheral neuropathy and brush-evoked allodynia, i.e. dynamic mechanical allodynia. Brush-evoked allodynia was induced in the innervation territory of the lesioned nervous structure in 18 patients by lightly stroking different distances of the skin (20, 40, 60 mm) two or four times with brushes of different widths (4, 8, 16 mm). Pain intensity and duration of brush-evoked allodynia was recorded using a computerized visual analogue scale. The total brush-evoked pain intensity, including painful aftersensation was calculated as the area under the curve. Following each stimulus, the patients selected pain descriptors from a validated instrument. Significantly increased total brush-evoked pain intensity was demonstrated with increased brushing length and number of strokes ( P<0.001), but not while altering brush width. Lack of influence of brush width was further underlined by the finding that activation of equivalent areas (e.g. 160 mm 2) resulted in higher total brush-evoked pain intensity if brushing the skin with a thin brush (4 mm) over a longer distance (40 mm) than a thick brush (8 mm) over a shorter distance (20 mm). Significantly increased duration of aftersensation was demonstrated only following increased brushing length ( P<0.008). The most commonly used sensory-discriminative pain descriptors were pricking, burning and sore and for the affective descriptors, annoying and troublesome. This is the first study demonstrating a relationship between evoked pain and some temporo-spatial stimulus parameters during brush-evoked allodynia.

P.5.044 Psychological features of patients withmigraine

Objectives: The primary objective of this study was to assess the efficacy and tolerability of tapentadol immediate release (IR) in patients who were candidates for joint replacement surgery due to end-stage joint disease. A secondary objective was to compare tapentadol IR with oxycodone HCl IR with respect to efficacy and prespecified tolerability end points.Methods: This 10-day, Phase III, randomized, double-blind, active- and placebo-controlled study compared the efficacy and tolerability of tapentadol IR, oxycodone HCl IR, and placebo in patients with uncontrolled osteoarthritis pain who were candidates for primary replacement of the hip or knee as a result of end-stage degenerative joint disease. Patients received tapentadol IR 50 mg, tapentadol IR 75 mg, oxycodone HCl IR 10 mg, or placebo every 4 to 6 hours during waking hours. The primary end point was the sum of pain intensity difference (SPID) over 5 days. Secondary efficacy end points included 2- and 10-day SPID; 2-, 5-, and 10-day total pain relief (TOTPAR); and the sum of total pain relief and pain intensity difference (SPRID). Prespecified noninferiority comparisons with oxycodone HCl IR were performed with respect to efficacy (based on 5-day SPID) and tolerability (based on incidence of the reported adverse events (AEs) of nausea and/or vomiting and constipation).Results: Of 666 patients originally enrolled, 659 were included in the efficacy analysis (51% male; 91% white; mean age, 61.2 years; mean weight, 97 kg). Five-day SPID was significantly lower in those treated with tapentadol IR (tapentadol IR 50 mg: least squares mean difference [LSMD] = 101.2 [95% CI, 54.58- 147.89]; tapentadol IR 75 mg: LSMD = 97.5 [95% CI, 51.81-143.26]) or oxycodone HCl IR (LSMD = 111.9 [95% CI, 66.49-157.38]) (all, P < 0.001). Tapentadol IR 50 and 75 mg and oxycodone HCl IR 10 mg were associated with significant reductions in pain intensity compared with placebo, based on 2- and 10-day SPID and 2-, 5-, and 10-day TOTPAR and SPRID (all, P < 0.001). The efficacy of tapentadol IR 50 and 75 mg was noninferior to that of oxycodone HCl IR 10 mg; however, the incidence of selected gastrointestinal AEs (nausea, vomiting, and constipation) was significantly lower for both doses of tapentadol IR compared with oxycodone HCl IR 10 mg (nominal P < 0.001). The odds ratios for nausea and/or vomiting for tapentadol IR 50 and 75 mg relative to oxycodone HCl IR 10 mg were 0.21 (95% CI, 0.128-0.339) and 0.32 (95% CI, 0.204-0.501), respectively; for constipation, the corresponding odds ratios were 0.13 (95% CI, 0.057-0.302) and 0.20 (95% CI, 0.098-0.398). Rates of treatment discontinuation were 18% (28/157) in the tapentadol IR 50-mg group, 26% (43/168) in the tapentadol IR 75-mg group, 35% (60/172) in the oxycodone HCl IR 10-mg group, and 10% (17/169) in the placebo group. In a post hoc analysis, tapentadol IR 50 mg was associated with a significantly lower incidence of treatment discontinuation than was oxycodone HCl IR 10 mg (P < 0.001).Conclusions: In these patients with uncontrolled osteoarthritis pain who were awaiting joint replacement surgery, tapentadol IR 50 and 75 mg were associated with analgesia that was noninferior to that provided by oxycodone HCl IR 10 mg. Tapentadol treatment was associated with improved gastrointestinal tolerability. ClinicalTrials.gov Identifier: NCT00361582.

Anticonvulsants: Efficacy and tolerability of oxcarbazepine in the treatment of neuropathic pain

The objective of this trial was to evaluate the safety, tolerability, and efficacy of oxcarbazepine in the treatment of painful neuropathies. This was an open-label, nine-week trial, consisting of a one-week prospective Screening Phase followed by an eight-week Treatment Phase. Treatment with oxcarbazepine was initiated at 150 mg/day and the daily dose was increased on a 2-3 days basis to tolerability over four weeks, up to 1200 mg/day. This was followed by a four-week fixed-dose Maintenance Phase during which patients were maintained on oxcarbazepine. The primary efficacy variable was the change in the weekly pain rating scale assessed on the VAS of the short-form McGill Pain Questionnaire (SF-MPQ) between the Screening Phase and the Treatment Phase. In addition, the short-form 36 Quality of life (SF-36 QOL) was completed at the baseline visit and at the end of the treatment phase. All analysis were performed on the intent-to-treat population. Twenty patients were enrolled in the trial. The mean daily oxcarbazepine dose during the Maintenance Phase was 870 mg. The mean VAS score dropped from 69.85 during the Screening Phase to 29.45 at the end of the trial (p <0.0001), for a mean reduction of - 40.40 (42.16 %). Moreover there were significant improvements in the total pain score and present pain intensity scores from the SF-MPQ and SF-36 QOL. Oxcarbazepine was well tolerated with the most common adverse events consisting of dizziness, and gastric symptoms. The results suggest that oxcarbazepine administered as monotherapy is an efficacious and safe option for the symptomatic treatment of pain associated with neuropathies. These results will need to be confirmed in large, double-blind, placebo controlled, randomized clinical trials

Pain and uterine contractions during breast feeding in the immediate post-partum period increase with parity

Previous research has shown that post-partum abdominal pain is greater in multiparous than primiparous women ( Murray and Holdcroft, 1989). Although breast feeding in the immediate post-partum period induces uterine contractions and abdominal pain, it is unknown how parity influences the contractions. Here, a structured questionnaire that included the McGill Pain Questionnaire (total pain intensity index, TPI) and visual analog scales (VAS) was used to evaluate the intensity, location, referred tenderness (hyperalgesia), descriptor, and temporal characteristics of pain during breast feeding up to three days after uncomplicated vaginal delivery. Three groups of women were studied: primiparous ( n=25); low parity (1–2 prior births; n=14); high parity (3–5 prior births; n=11). Uterine contractions during breast feeding were recorded using tocodynamometry in some women from each group ( n=17, 6, 7, respectively). For comparison, an identical questionnaire was used to evaluate pains the women remembered experiencing during menstruation in the year immediately preceding the current pregnancy. During breast feeding, nearly all women (96%) reported deep pain primarily at three sites: lower abdomen, low back, and breast, with associated referred hyperalgesia in 62% of them. The intensity of these pains increased significantly with parity ( P<0.001), along with an increase in the number of pain sites ( P=0.03), mainly in lower abdomen and back, but not breast. Similarly, both the mean duration and number of uterine contractions increased significantly with parity ( P<0.001). Furthermore, the mean duration of contractions correlated significantly with the pain scores ( P=0.03 [VAS] and P=0.006 [TPI]). In contrast with pain during breast feeding, the intensity of pain during menstruation did not change with parity. These results demonstrate that pain, referred pain, and uterine contractions during breast feeding in the immediate post-partum period increase with parity, suggesting that childbirth can induce central neural changes that increase predisposition for pain during the post-partum period.

The lens model: assessment of cancer pain in a Chinese context.

Obtaining a result closest to patients' reports about pain is crucial in pain management. The literature in the West supports the view that there are cultural differences in perception, interpretation, and expression of pain. However, there has been minimal review in Chinese communities. Therefore, the concepts of cancer pain among Chinese patients with cancer were explored by data source triangulation. There were 33 informants: 18 adult Chinese patients with cancer who were in pain, 7 physicians, and 8 nurses. The interview dialogue was transcribed into written Chinese, followed by coding and categorization. There were no predetermined themes for categorization. The dialogue was coded according to the contextual meaning. The nature and number of categories depended entirely on the coding. Five dimensions were identified: functional, pharmacologic, pain belief and meanings, psychosocial, and emotional. With reference to the five dimensions, a lens model was constructed to explain the cancer pain experience in a Chinese context. In the lens model, two lenses were used to illustrate the relations of the dimensions and cancer pain experience in the Chinese context. The pain experience was named as total pain intensity. The functional, pharmacologic, psychosocial, and emotional dimensions were the independent variables. The pain beliefs and meanings dimension was the mediating variable, and the dependent variable was the total pain intensity in the assessment of cancer pain.