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Morin M, Morin A, Gougeon V, Marchand S, Waddell G, Bureau YA, Girard I, Brassard A, Benoit-Piau J, Léonard G. Transcranial direct current stimulation for provoked vestibulodynia: What roles do psychosexual factors play in treatment response? J Clin Neurosci 2021; 93:54-60. [PMID: 34656261 DOI: 10.1016/j.jocn.2021.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 07/16/2021] [Accepted: 08/01/2021] [Indexed: 11/29/2022]
Abstract
There is growing evidence that provoked vestibulodynia (PVD), a frequent and debilitating condition, is characterized by central sensitization. This study aimed to examine predictive factors of transcranial direct current stimulation (tDCS) efficacy in this chronic pain population. Exploratory analysis derived from a randomized controlled trial was performed to assess predictors of pain reduction among 39 women with PVD who received 10 daily sessions of either active or sham tDCS. Clinical characteristics (e.g. pain intensity, duration and pain sensitivity) and psychosexual factors (e.g. pain catastrophizing, pain-related fear, anxiety, depressive symptoms and vaginal penetration cognitions) were assessed at baseline and used to predict tDCS response at 3-month follow-up. Analysis revealed that higher depressive symptoms and lower negative self-image cognitions were significant predictors of pain reduction at follow-up and accounted for 62.3% of the variance in the active tDCS group. Higher genital incompatibility cognitions were related to poorer response, regardless of treatment group. These findings suggest that women with PVD presenting higher depressive symptoms and lower levels of negative self-image cognitions could derive greater benefits from tDCS. These results suggest that tDCS could be effective in a subgroup of women with PVD - a possibility worth exploring with future prospective larger studies.
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Affiliation(s)
- Mélanie Morin
- School of Rehabilitation, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, Québec J1H 5N4, Canada
| | - Annie Morin
- School of Rehabilitation, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, Québec J1H 5N4, Canada
| | - Véronique Gougeon
- School of Rehabilitation, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, Québec J1H 5N4, Canada
| | - Serge Marchand
- Department of Surgery, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, Québec J1H 5N4, Canada
| | - Guy Waddell
- Department of Obstetrics Gynecology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, Québec J1H 5N4, Canada
| | - Yves-André Bureau
- School of Rehabilitation, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, Québec J1H 5N4, Canada
| | - Isabelle Girard
- Department of Obstetrics Gynecology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, Québec J1H 5N4, Canada
| | - Audrey Brassard
- Department of Psychology, Faculty of Arts and Social Sciences, 2500 blvd Université, Sherbrooke, Québec J1K 2Rl, Canada
| | - Justine Benoit-Piau
- School of Rehabilitation, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, Québec J1H 5N4, Canada
| | - Guillaume Léonard
- School of Rehabilitation, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001 12th Avenue North, Sherbrooke, Québec J1H 5N4, Canada.
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Abstract
BACKGROUND This review updates part of an earlier Cochrane Review titled "Pregabalin for acute and chronic pain in adults", and considers only neuropathic pain (pain from damage to nervous tissue). Antiepileptic drugs have long been used in pain management. Pregabalin is an antiepileptic drug used in management of chronic pain conditions. OBJECTIVES To assess the analgesic efficacy and adverse effects of pregabalin for chronic neuropathic pain in adults. SEARCH METHODS We searched CENTRAL, MEDLINE, and Embase for randomised controlled trials from January 2009 to April 2018, online clinical trials registries, and reference lists. SELECTION CRITERIA We included randomised, double-blind trials of two weeks' duration or longer, comparing pregabalin (any route of administration) with placebo or another active treatment for neuropathic pain, with participant-reported pain assessment. DATA COLLECTION AND ANALYSIS Two review authors independently extracted data and assessed trial quality and biases. Primary outcomes were: at least 30% pain intensity reduction over baseline; much or very much improved on the Patient Global Impression of Change (PGIC) Scale (moderate benefit); at least 50% pain intensity reduction; or very much improved on PGIC (substantial benefit). We calculated risk ratio (RR) and number needed to treat for an additional beneficial (NNTB) or harmful outcome (NNTH). We assessed the quality of the evidence using GRADE. MAIN RESULTS We included 45 studies lasting 2 to 16 weeks, with 11,906 participants - 68% from 31 new studies. Oral pregabalin doses of 150 mg, 300 mg, and 600 mg daily were compared with placebo. Postherpetic neuralgia, painful diabetic neuropathy, and mixed neuropathic pain predominated (85% of participants). High risk of bias was due mainly to small study size (nine studies), but many studies had unclear risk of bias, mainly due to incomplete outcome data, size, and allocation concealment.Postherpetic neuralgia: More participants had at least 30% pain intensity reduction with pregabalin 300 mg than with placebo (50% vs 25%; RR 2.1 (95% confidence interval (CI) 1.6 to 2.6); NNTB 3.9 (3.0 to 5.6); 3 studies, 589 participants, moderate-quality evidence), and more had at least 50% pain intensity reduction (32% vs 13%; RR 2.5 (95% CI 1.9 to 3.4); NNTB 5.3 (3.9 to 8.1); 4 studies, 713 participants, moderate-quality evidence). More participants had at least 30% pain intensity reduction with pregabalin 600 mg than with placebo (62% vs 24%; RR 2.5 (95% CI 2.0 to 3.2); NNTB 2.7 (2.2 to 3.7); 3 studies, 537 participants, moderate-quality evidence), and more had at least 50% pain intensity reduction (41% vs 15%; RR 2.7 (95% CI 2.0 to 3.5); NNTB 3.9 (3.1 to 5.5); 4 studies, 732 participants, moderate-quality evidence). Somnolence and dizziness were more common with pregabalin than with placebo (moderate-quality evidence): somnolence 300 mg 16% versus 5.5%, 600 mg 25% versus 5.8%; dizziness 300 mg 29% versus 8.1%, 600 mg 35% versus 8.8%.Painful diabetic neuropathy: More participants had at least 30% pain intensity reduction with pregabalin 300 mg than with placebo (47% vs 42%; RR 1.1 (95% CI 1.01 to 1.2); NNTB 22 (12 to 200); 8 studies, 2320 participants, moderate-quality evidence), more had at least 50% pain intensity reduction (31% vs 24%; RR 1.3 (95% CI 1.2 to 1.5); NNTB 22 (12 to 200); 11 studies, 2931 participants, moderate-quality evidence), and more had PGIC much or very much improved (51% vs 30%; RR 1.8 (95% CI 1.5 to 2.0); NNTB 4.9 (3.8 to 6.9); 5 studies, 1050 participants, moderate-quality evidence). More participants had at least 30% pain intensity reduction with pregabalin 600 mg than with placebo (63% vs 52%; RR 1.2 (95% CI 1.04 to 1.4); NNTB 9.6 (5.5 to 41); 2 studies, 611 participants, low-quality evidence), and more had at least 50% pain intensity reduction (41% vs 28%; RR 1.4 (95% CI 1.2 to 1.7); NNTB 7.8 (5.4 to 14); 5 studies, 1015 participants, low-quality evidence). Somnolence and dizziness were more common with pregabalin than with placebo (moderate-quality evidence): somnolence 300 mg 11% versus 3.1%, 600 mg 15% versus 4.5%; dizziness 300 mg 13% versus 3.8%, 600 mg 22% versus 4.4%.Mixed or unclassified post-traumatic neuropathic pain: More participants had at least 30% pain intensity reduction with pregabalin 600 mg than with placebo (48% vs 36%; RR 1.2 (1.1 to 1.4); NNTB 8.2 (5.7 to 15); 4 studies, 1367 participants, low-quality evidence), and more had at least 50% pain intensity reduction (34% vs 20%; RR 1.5 (1.2 to 1.9); NNTB 7.2 (5.4 to 11); 4 studies, 1367 participants, moderate-quality evidence). Somnolence (12% vs 3.9%) and dizziness (23% vs 6.2%) were more common with pregabalin.Central neuropathic pain: More participants had at least 30% pain intensity reduction with pregabalin 600 mg than with placebo (44% vs 28%; RR 1.6 (1.3 to 2.0); NNTB 5.9 (4.1 to 11); 3 studies, 562 participants, low-quality evidence) and at least 50% pain intensity reduction (26% vs 15%; RR 1.7 (1.2 to 2.3); NNTB 9.8 (6.0 to 28); 3 studies, 562 participants, low-quality evidence). Somnolence (32% vs 11%) and dizziness (23% vs 8.6%) were more common with pregabalin.Other neuropathic pain conditions: Studies show no evidence of benefit for 600 mg pregabalin in HIV neuropathy (2 studies, 674 participants, moderate-quality evidence) and limited evidence of benefit in neuropathic back pain or sciatica, neuropathic cancer pain, or polyneuropathy.Serious adverse events, all conditions: Serious adverse events were no more common with placebo than with pregabalin 300 mg (3.1% vs 2.6%; RR 1.2 (95% CI 0.8 to 1.7); 17 studies, 4112 participants, high-quality evidence) or pregabalin 600 mg (3.4% vs 3.4%; RR 1.1 (95% CI 0.8 to 1.5); 16 studies, 3995 participants, high-quality evidence). AUTHORS' CONCLUSIONS Evidence shows efficacy of pregabalin in postherpetic neuralgia, painful diabetic neuralgia, and mixed or unclassified post-traumatic neuropathic pain, and absence of efficacy in HIV neuropathy; evidence of efficacy in central neuropathic pain is inadequate. Some people will derive substantial benefit with pregabalin; more will have moderate benefit, but many will have no benefit or will discontinue treatment. There were no substantial changes since the 2009 review.
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Affiliation(s)
| | - Rae Frances Bell
- Haukeland University HospitalRegional Centre of Excellence in Palliative CareBergenNorway
| | - Sebastian Straube
- University of AlbertaDepartment of Medicine, Division of Preventive Medicine5‐30 University Terrace8303‐112 StreetEdmontonCanadaT6G 2T4
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Alev L, Fujikoshi S, Yoshikawa A, Enomoto H, Ishida M, Tsuji T, Ogawa K, Konno S. Duloxetine 60 mg for chronic low back pain: post hoc responder analysis of double-blind, placebo-controlled trials. J Pain Res 2017; 10:1723-1731. [PMID: 28769588 PMCID: PMC5533563 DOI: 10.2147/jpr.s138297] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Introduction Duloxetine has demonstrated efficacy in chronic low back pain (CLBP). We examined the predictors of response to duloxetine for CLBP. Patients and methods This was a post hoc analysis of pooled data from 4 double-blind, ran-domized, placebo-controlled trials of duloxetine (60 mg/day for 12–14 weeks) in adult patients with CLBP. Primary outcome was proportion of patients with ≥30% reduction in Brief Pain Inventory (BPI) average pain (“pain reduction”) at 12–14 weeks. The proportion of patients with ≥30% and ≥50% (secondary outcome) pain reduction in duloxetine and placebo groups was compared. Variables for responder analyses were early improvement (≥15% pain reduction at Week 2), sex, age, baseline BPI average pain score, duration of CLBP, and number of painful body sites according to the Michigan Body Map (≥2 vs 1 [isolated CLBP]; 1 trial); relative risk (RR) and 95% confidence interval (CI) were calculated. Results Compared with placebo (n = 653), a greater proportion of duloxetine-treated patients (n = 642) achieved ≥30% (59.7% vs 47.8%; P < 0.001) and ≥50% pain reduction (48.6% vs 35.1%; P < 0.001). Among duloxetine-treated patients, early improvement was associated with greater likelihood of ≥30% (RR [95% CI], 2.91 [2.30–3.67]) or ≥50% (3.24 [2.44–4.31]) pain reduction. Women were slightly more likely than men to achieve ≥30% (RR [95% CI], 1.14 [1.00–1.30]) or ≥50% (1.17 [0.99–1.38]) pain reduction. Response rates were similar between age, CLBP duration, and baseline BPI average pain score subgroups. Patients with ≥2 painful sites were more likely to respond to duloxetine 60 mg relative to placebo than patients with isolated CLBP (RR, duloxetine vs placebo [95% CI]: ≥30% reduction, ≥2 painful sites 1.40 [1.18–1.66], isolated CLBP 1.07 [0.78–1.48]; ≥50% reduction, ≥2 painful sites 1.51 [1.20–1.89], isolated CLBP 1.23 [0.81–1.88]). Conclusion Early pain reduction was indicative of overall response. Patients with multiple painful sites had more benefit from duloxetine than patients with isolated CLBP.
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Affiliation(s)
| | | | - Aki Yoshikawa
- Scientific Communications, Medicines Development Unit, Eli Lilly Japan K.K., Kobe
| | | | | | | | | | - Shinichi Konno
- Department of Orthopedic Surgery, Fukushima Medical University, Fukushima, Japan
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Wiffen PJ, Derry S, Bell RF, Rice ASC, Tölle TR, Phillips T, Moore RA. Gabapentin for chronic neuropathic pain in adults. Cochrane Database Syst Rev 2017; 6:CD007938. [PMID: 28597471 PMCID: PMC6452908 DOI: 10.1002/14651858.cd007938.pub4] [Citation(s) in RCA: 161] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Gabapentin is commonly used to treat neuropathic pain (pain due to nerve damage). This review updates a review published in 2014, and previous reviews published in 2011, 2005 and 2000. OBJECTIVES To assess the analgesic efficacy and adverse effects of gabapentin in chronic neuropathic pain in adults. SEARCH METHODS For this update we searched CENTRAL), MEDLINE, and Embase for randomised controlled trials from January 2014 to January 2017. We also searched the reference lists of retrieved studies and reviews, and online clinical trials registries. SELECTION CRITERIA We included randomised, double-blind trials of two weeks' duration or longer, comparing gabapentin (any route of administration) with placebo or another active treatment for neuropathic pain, with participant-reported pain assessment. DATA COLLECTION AND ANALYSIS Two review authors independently extracted data and assessed trial quality and potential bias. Primary outcomes were participants with substantial pain relief (at least 50% pain relief over baseline or very much improved on Patient Global Impression of Change scale (PGIC)), or moderate pain relief (at least 30% pain relief over baseline or much or very much improved on PGIC). We performed a pooled analysis for any substantial or moderate benefit. Where pooled analysis was possible, we used dichotomous data to calculate risk ratio (RR) and number needed to treat for an additional beneficial outcome (NNT) or harmful outcome (NNH). We assessed the quality of the evidence using GRADE and created 'Summary of findings' tables. MAIN RESULTS We included four new studies (530 participants), and excluded three previously included studies (126 participants). In all, 37 studies provided information on 5914 participants. Most studies used oral gabapentin or gabapentin encarbil at doses of 1200 mg or more daily in different neuropathic pain conditions, predominantly postherpetic neuralgia and painful diabetic neuropathy. Study duration was typically four to 12 weeks. Not all studies reported important outcomes of interest. High risk of bias occurred mainly due to small size (especially in cross-over studies), and handling of data after study withdrawal.In postherpetic neuralgia, more participants (32%) had substantial benefit (at least 50% pain relief or PGIC very much improved) with gabapentin at 1200 mg daily or greater than with placebo (17%) (RR 1.8 (95% CI 1.5 to 2.1); NNT 6.7 (5.4 to 8.7); 8 studies, 2260 participants, moderate-quality evidence). More participants (46%) had moderate benefit (at least 30% pain relief or PGIC much or very much improved) with gabapentin at 1200 mg daily or greater than with placebo (25%) (RR 1.8 (95% CI 1.6 to 2.0); NNT 4.8 (4.1 to 6.0); 8 studies, 2260 participants, moderate-quality evidence).In painful diabetic neuropathy, more participants (38%) had substantial benefit (at least 50% pain relief or PGIC very much improved) with gabapentin at 1200 mg daily or greater than with placebo (21%) (RR 1.9 (95% CI 1.5 to 2.3); NNT 5.9 (4.6 to 8.3); 6 studies, 1277 participants, moderate-quality evidence). More participants (52%) had moderate benefit (at least 30% pain relief or PGIC much or very much improved) with gabapentin at 1200 mg daily or greater than with placebo (37%) (RR 1.4 (95% CI 1.3 to 1.6); NNT 6.6 (4.9 to 9.9); 7 studies, 1439 participants, moderate-quality evidence).For all conditions combined, adverse event withdrawals were more common with gabapentin (11%) than with placebo (8.2%) (RR 1.4 (95% CI 1.1 to 1.7); NNH 30 (20 to 65); 22 studies, 4346 participants, high-quality evidence). Serious adverse events were no more common with gabapentin (3.2%) than with placebo (2.8%) (RR 1.2 (95% CI 0.8 to 1.7); 19 studies, 3948 participants, moderate-quality evidence); there were eight deaths (very low-quality evidence). Participants experiencing at least one adverse event were more common with gabapentin (63%) than with placebo (49%) (RR 1.3 (95% CI 1.2 to 1.4); NNH 7.5 (6.1 to 9.6); 18 studies, 4279 participants, moderate-quality evidence). Individual adverse events occurred significantly more often with gabapentin. Participants taking gabapentin experienced dizziness (19%), somnolence (14%), peripheral oedema (7%), and gait disturbance (14%). AUTHORS' CONCLUSIONS Gabapentin at doses of 1800 mg to 3600 mg daily (1200 mg to 3600 mg gabapentin encarbil) can provide good levels of pain relief to some people with postherpetic neuralgia and peripheral diabetic neuropathy. Evidence for other types of neuropathic pain is very limited. The outcome of at least 50% pain intensity reduction is regarded as a useful outcome of treatment by patients, and the achievement of this degree of pain relief is associated with important beneficial effects on sleep interference, fatigue, and depression, as well as quality of life, function, and work. Around 3 or 4 out of 10 participants achieved this degree of pain relief with gabapentin, compared with 1 or 2 out of 10 for placebo. Over half of those treated with gabapentin will not have worthwhile pain relief but may experience adverse events. Conclusions have not changed since the previous update of this review.
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Affiliation(s)
| | | | - Rae Frances Bell
- Haukeland University HospitalRegional Centre of Excellence in Palliative CareBergenNorway
| | - Andrew SC Rice
- Imperial College LondonPain Research, Department of Surgery and Cancer, Faculty of MedicineLondonUKSW10 9NH
| | - Thomas Rudolf Tölle
- Technische Universität MünchenDepartment of Neurology, Klinikum Rechts der IsarMöhlstrasse 28MunichGermany81675
| | - Tudor Phillips
- University of OxfordPain Research and Nuffield Department of Clinical Neurosciences (Nuffield Division of Anaesthetics)Churchill HospitalOxfordUKOX3 7LJ
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Shimony N, Amit U, Minz B, Grossman R, Dany MA, Gonen L, Kandov K, Ram Z, Weinbroum AA. Perioperative pregabalin for reducing pain, analgesic consumption, and anxiety and enhancing sleep quality in elective neurosurgical patients: a prospective, randomized, double-blind, and controlled clinical study. J Neurosurg 2016; 125:1513-1522. [DOI: 10.3171/2015.10.jns151516] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE
The aim of this study was to assess in-hospital (immediate) postoperative pain scores and analgesic consumption (primary goals) and preoperative anxiety and sleep quality (secondary goals) in patients who underwent craniotomy and were treated with pregabalin (PGL). Whenever possible, out-of-hospital pain scores and analgesics usage data were obtained as well.
METHODS
This prospective, randomized, double-blind and controlled study was conducted in consenting patients who underwent elective craniotomy for brain tumor resection at Tel Aviv Medical Center between 2012 and 2014. Patients received either 150 mg PGL (n = 50) or 500 mg starch (placebo; n = 50) on the evening before surgery, 1.5 hours before surgery, and twice daily for 72 hours following surgery. All patients spent the night before surgery in the hospital, and no other premedication was administered. Opioids and nonsteroidal antiinflammatory drugs were used for pain, which was self-rated by means of a numerical rating scale (score range 0–10).
RESULTS
Eighty-eight patients completed the study. Data on the American Society of Anesthesiologists class, age, body weight, duration of surgery, and intraoperative drugs were similar for both groups. The pain scores during postoperative Days 0 to 2 were significantly lower in the PGL group than in the placebo group (p < 0.01). Analgesic consumption was also lower in the PGL group, both immediately and 1 month after surgery. There were fewer requests for antiemetics in the PGL group, and the rate of postoperative nausea and vomiting was lower. The preoperative anxiety level and the quality of sleep were significantly better in the PGL group (p < 0.01). There were no PGL-associated major adverse events.
CONCLUSIONS
Perioperative use of twice-daily 150 mg pregabalin attenuates preoperative anxiety, improves sleep quality, and reduces postoperative pain scores and analgesic usage without increasing the rate of adverse effects.
Clinical trial registration no.: NCT01612832 (clinicaltrials.gov)
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Affiliation(s)
- Nir Shimony
- 2Neurosurgery, Tel Aviv Sourasky Medical Center and the Sackler Faculty of Medicine at the Tel Aviv University, Tel Aviv, Israel
| | - Uri Amit
- Departments of 1Anesthesia and Post-Anesthesia Care Unit and
| | - Bella Minz
- 2Neurosurgery, Tel Aviv Sourasky Medical Center and the Sackler Faculty of Medicine at the Tel Aviv University, Tel Aviv, Israel
| | - Rachel Grossman
- 2Neurosurgery, Tel Aviv Sourasky Medical Center and the Sackler Faculty of Medicine at the Tel Aviv University, Tel Aviv, Israel
| | - Marc A. Dany
- Departments of 1Anesthesia and Post-Anesthesia Care Unit and
| | - Lior Gonen
- 2Neurosurgery, Tel Aviv Sourasky Medical Center and the Sackler Faculty of Medicine at the Tel Aviv University, Tel Aviv, Israel
| | - Karina Kandov
- 2Neurosurgery, Tel Aviv Sourasky Medical Center and the Sackler Faculty of Medicine at the Tel Aviv University, Tel Aviv, Israel
| | - Zvi Ram
- 2Neurosurgery, Tel Aviv Sourasky Medical Center and the Sackler Faculty of Medicine at the Tel Aviv University, Tel Aviv, Israel
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Kantor D, Panchal S, Patel V, Bucior I, Rauck R. Treatment of Postherpetic Neuralgia With Gastroretentive Gabapentin: Interaction of Patient Demographics, Disease Characteristics, and Efficacy Outcomes. THE JOURNAL OF PAIN 2015; 16:1300-1311. [PMID: 26409117 DOI: 10.1016/j.jpain.2015.08.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/28/2015] [Accepted: 08/11/2015] [Indexed: 10/23/2022]
Abstract
UNLABELLED To understand how patient demographics and patient-reported disease characteristics relate to successful management of postherpetic neuralgia (PHN), integrated data from phase 3 and phase 4 studies of patients with PHN (n = 546) who received once-daily gastroretentive gabapentin (G-GR, 1800 mg) were analyzed. There were widespread, networked, positive correlations among efficacy end points--pain qualities on the visual analog scale (VAS) and Brief Pain Inventory (BPI), measures of pain interference on the BPI, and Patient Global Impression of Change (PGIC)--most likely characterized by positive feedback loops, in which pain interferes with patient functioning, and poor functioning enhances pain. VAS scores at baseline or at week 2 were the strongest predictors of being "much" or "very much" improved on the PGIC; BPI sleep interference scores were the strongest predictors of percent changes in BPI pain qualities and in the average of BPI interference scores, whereas age, sex, and race were not important predictors. In addition to VAS, BPI sleep interference and PGIC assessments appeared to be key co-strategic factors important for successful treatment outcomes, and should be considered as co-primary end points in future clinical trials of PHN. This could improve detection of true positive efficacy responses and guide successful transition to real-world clinical practice. PERSPECTIVE This study describes complex relationships among measures of pain intensity, pain interference with daily activities, and demographics of patients with PHN treated with G-GR. Such comprehensive characterization provides important insight into how different variables contribute to successful treatment, and may lead to better management of neuropathic pain.
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Affiliation(s)
| | | | - Vikram Patel
- Phoenix Interventional, LLC, Algonquin, Illinois
| | | | - Richard Rauck
- Carolinas Pain Institute, Winston-Salem, North Carolina
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Abstract
BACKGROUND This review is an update of a review published in 2011, itself a major update of previous reviews published in 2005 and 2000, investigating the effects of gabapentin in chronic neuropathic pain (pain due to nerve damage). Antiepileptic drugs are used to manage chronic neuropathic pain and fibromyalgia. OBJECTIVES To assess the analgesic efficacy and adverse effects of gabapentin in chronic neuropathic pain and fibromyalgia. SEARCH METHODS We identified randomised trials of gabapentin for chronic neuropathic pain or fibromyalgia by searching the databases MEDLINE (1966 to March 2014), EMBASE (1980 to 2014 week 10), and CENTRAL in The Cochrane Library (Issue 3 of 12, 2014). We obtained clinical trial reports and synopses of published and unpublished studies from Internet sources, and searched Clinicaltrials.gov. Searches were run originally in 2011 and the date of the most recent search was 17 March 2014. SELECTION CRITERIA Randomised, double-blind studies reporting the analgesic and adverse effects of gabapentin in neuropathic pain or fibromyalgia with assessment of pain intensity, pain relief, or both, using validated scales. Participants were adults. DATA COLLECTION AND ANALYSIS Three review authors independently extracted efficacy and adverse event data, examined issues of study quality, and assessed risk of bias. We performed analysis using three tiers of evidence. First tier evidence derived from data meeting current best standards and subject to minimal risk of bias (outcome equivalent to substantial pain intensity reduction, intention-to-treat analysis without imputation for dropouts; at least 200 participants in the comparison, 8 to 12 weeks duration, parallel design), second tier from data that failed to meet one or more of these criteria and were considered at some risk of bias but with adequate numbers in the comparison, and third tier from data involving small numbers of participants that were considered very likely to be biased or used outcomes of limited clinical utility, or both.For efficacy, we calculated the number needed to treat to benefit (NNT), concentrating on at least 50% pain intensity reduction, and Initiative on Methods, Measurement and Pain Assessment in Clinical Trials (IMMPACT) definitions of at least moderate and substantial benefit. For harm we calculated number needed to treat for harm (NNH) for adverse effects and withdrawal. Meta-analysis was undertaken using a fixed-effect model. We emphasised differences between conditions now defined as neuropathic pain, and other conditions like masticatory pain, complex regional painsyndrome type 1 (CRPS-1), and fibromyalgia. MAIN RESULTS Seven new studies with 1919 participants were added. Another report (147 participants) provided results for a study already included, but which previously had no usable data. A further report (170 participants) used an experimental formulation of intrathecal gabapentin. Thirty-seven studies (5633 participants) studied oral gabapentin at daily doses of 1200 mg or more in 12 chronic pain conditions; 84% of participants were in studies of postherpetic neuralgia, painful diabetic neuropathy or mixed neuropathic pain. There was no first tier evidence.Second tier evidence for the outcome of at least 50% pain intensity reduction, considered valuable by patients with chronic pain, showed that gabapentin was significantly better than placebo in postherpetic neuralgia (34% gabapentin versus 21% placebo; NNT 8.0, 95% CI 6.0 to 12) and painful diabetic neuropathy (38% versus 21%, NNT 5.9, 95% CI 4.6 to 8.3). There was insufficient information in other pain conditions to reach any reliable conclusion. There was no obvious difference between standard gabapentin formulations and recently-introduced extended-release or gastro-retentive formulations, or between different doses of gabapentin.Adverse events occurred significantly more often with gabapentin. Persons taking gabapentin could expect to have at least one adverse event (62%), withdraw because of an adverse event (11%), suffer dizziness (19%), somnolence (14%), peripheral oedema (7%), and gait disturbance (9%). Serious adverse events (3%) were no more common than with placebo.There were insufficient data for direct comparisons with other active treatments, and only third tier evidence for other painful conditions. AUTHORS' CONCLUSIONS There was no top tier evidence that was unequivocally unbiased. Second tier evidence, with potentially important residual biases, showed that gabapentin at doses of 1200 mg or more was effective for some people with some painful neuropathic pain conditions. The outcome of at least 50% pain intensity reduction is regarded as a useful outcome of treatment by patients, and the achievement of this degree of pain relief is associated with important beneficial effects on sleep interference, fatigue, and depression, as well as quality of life, function, and work. About 35% achieved this degree of pain relief with gabapentin, compared with 21% for placebo. Over half of those treated with gabapentin will not have worthwhile pain relief. Results might vary between different neuropathic pain conditions, and the amount of evidence for gabapentin in neuropathic pain conditions except postherpetic neuralgia and painful diabetic neuropathy, and in fibromyalgia, is very limited.The levels of efficacy found for gabapentin are consistent with those found for other drug therapies in postherpetic neuralgia and painful diabetic neuropathy.
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Affiliation(s)
- R Andrew Moore
- University of OxfordPain Research and Nuffield Department of Clinical Neurosciences (Nuffield Division of Anaesthetics)Pain Research UnitChurchill HospitalOxfordUKOX3 7LE
| | - Philip J Wiffen
- University of OxfordPain Research and Nuffield Department of Clinical Neurosciences (Nuffield Division of Anaesthetics)Pain Research UnitChurchill HospitalOxfordUKOX3 7LE
| | - Sheena Derry
- University of OxfordPain Research and Nuffield Department of Clinical Neurosciences (Nuffield Division of Anaesthetics)Pain Research UnitChurchill HospitalOxfordUKOX3 7LE
| | - Andrew SC Rice
- Imperial College LondonPain Research, Department of Surgery and Cancer, Faculty of MedicineLondonUKSW10 9NH
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Moore RA, Wiffen PJ, Derry S, Toelle T, Rice ASC. Gabapentin for chronic neuropathic pain and fibromyalgia in adults. THE COCHRANE DATABASE OF SYSTEMATIC REVIEWS 2014. [PMID: 24771480 DOI: 10.1002/14651858.cd007938] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND This review is an update of a review published in 2011, itself a major update of previous reviews published in 2005 and 2000, investigating the effects of gabapentin in chronic neuropathic pain (pain due to nerve damage). Antiepileptic drugs are used to manage chronic neuropathic pain and fibromyalgia. OBJECTIVES To assess the analgesic efficacy and adverse effects of gabapentin in chronic neuropathic pain and fibromyalgia. SEARCH METHODS We identified randomised trials of gabapentin for chronic neuropathic pain or fibromyalgia by searching the databases MEDLINE (1966 to March 2014), EMBASE (1980 to 2014 week 10), and CENTRAL in The Cochrane Library (Issue 3 of 12, 2014). We obtained clinical trial reports and synopses of published and unpublished studies from Internet sources, and searched Clinicaltrials.gov. Searches were run originally in 2011 and the date of the most recent search was 17 March 2014. SELECTION CRITERIA Randomised, double-blind studies reporting the analgesic and adverse effects of gabapentin in neuropathic pain or fibromyalgia with assessment of pain intensity, pain relief, or both, using validated scales. Participants were adults. DATA COLLECTION AND ANALYSIS Three review authors independently extracted efficacy and adverse event data, examined issues of study quality, and assessed risk of bias. We performed analysis using three tiers of evidence. First tier evidence derived from data meeting current best standards and subject to minimal risk of bias (outcome equivalent to substantial pain intensity reduction, intention-to-treat analysis without imputation for dropouts; at least 200 participants in the comparison, 8 to 12 weeks duration, parallel design), second tier from data that failed to meet one or more of these criteria and were considered at some risk of bias but with adequate numbers in the comparison, and third tier from data involving small numbers of participants that were considered very likely to be biased or used outcomes of limited clinical utility, or both.For efficacy, we calculated the number needed to treat to benefit (NNT), concentrating on at least 50% pain intensity reduction, and Initiative on Methods, Measurement and Pain Assessment in Clinical Trials (IMMPACT) definitions of at least moderate and substantial benefit. For harm we calculated number needed to treat for harm (NNH) for adverse effects and withdrawal. Meta-analysis was undertaken using a fixed-effect model. We emphasised differences between conditions now defined as neuropathic pain, and other conditions like masticatory pain, complex regional painsyndrome type 1 (CRPS-1), and fibromyalgia. MAIN RESULTS Seven new studies with 1919 participants were added. Another report (147 participants) provided results for a study already included, but which previously had no usable data. A further report (170 participants) used an experimental formulation of intrathecal gabapentin. Thirty-seven studies (5633 participants) studied oral gabapentin at daily doses of 1200 mg or more in 12 chronic pain conditions; 84% of participants were in studies of postherpetic neuralgia, painful diabetic neuropathy or mixed neuropathic pain. There was no first tier evidence.Second tier evidence for the outcome of at least 50% pain intensity reduction, considered valuable by patients with chronic pain, showed that gabapentin was significantly better than placebo in postherpetic neuralgia (34% gabapentin versus 21% placebo; NNT 8.0, 95% CI 6.0 to 12) and painful diabetic neuropathy (38% versus 21%, NNT 5.9, 95% CI 4.6 to 8.3). There was insufficient information in other pain conditions to reach any reliable conclusion. There was no obvious difference between standard gabapentin formulations and recently-introduced extended-release or gastro-retentive formulations, or between different doses of gabapentin.Adverse events occurred significantly more often with gabapentin. Persons taking gabapentin could expect to have at least one adverse event (62%), withdraw because of an adverse event (11%), suffer dizziness (19%), somnolence (14%), peripheral oedema (7%), and gait disturbance (9%). Serious adverse events (3%) were no more common than with placebo.There were insufficient data for direct comparisons with other active treatments, and only third tier evidence for other painful conditions. AUTHORS' CONCLUSIONS There was no top tier evidence that was unequivocally unbiased. Second tier evidence, with potentially important residual biases, showed that gabapentin at doses of 1200 mg or more was effective for some people with some painful neuropathic pain conditions. The outcome of at least 50% pain intensity reduction is regarded as a useful outcome of treatment by patients, and the achievement of this degree of pain relief is associated with important beneficial effects on sleep interference, fatigue, and depression, as well as quality of life, function, and work. About 35% achieved this degree of pain relief with gabapentin, compared with 21% for placebo. Over half of those treated with gabapentin will not have worthwhile pain relief. Results might vary between different neuropathic pain conditions, and the amount of evidence for gabapentin in neuropathic pain conditions except postherpetic neuralgia and painful diabetic neuropathy, and in fibromyalgia, is very limited.The levels of efficacy found for gabapentin are consistent with those found for other drug therapies in postherpetic neuralgia and painful diabetic neuropathy.
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Affiliation(s)
- R Andrew Moore
- Pain Research and Nuffield Department of Clinical Neurosciences, University of Oxford, Pain Research Unit, Churchill Hospital, Oxford, Oxfordshire, UK, OX3 7LE
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